# Building a 75g all glass tank



## scolley

Before you start this thread, about building a 75g glass tank, please be warned... This tank held for more than a year, but one side failed - catastrophically - one afternoon. IMO that should not discourage you from trying this. I discuss why it failed in this thread. Give it a read.

I understand why, and it is quite preventable. But I can't prove it.

- SCOLLEY June 9, 2007 



Introduction
I recently built a 75g (approx.) aquarium out of glass and silicone. No frame, no bracing. It was successful, but it was difficult. As I built it I tried to document the entire experience so that I could pass along the lessons I learned in that process.

I had intended to create a “How-To” document. But I’ve become uncomfortable with the concept of step-by-step instructions for a tank of that size. There are too many variables; too many things can go awry in the construction and assembly process, making step-by-step instructions useless. If you intend to build something like this yourself, your knowledge needs to be sufficient for you to create your own step-by-step instructions. Based on the information I’m providing here, and using the other sources I’ll reference, you should be able to do that. And more important, when something you don’t expect happens – like running out of silicone just as you are putting on the last pane of glass, for example – you’ll have enough knowledge to know what that means to your plans, and how to get your construction process back on course.

My own experience left me convinced that some of the techniques I used could be improved. But if you want to build such a thing yourself, the things I learned should help enable your success. 

I have a very long thread here that documents my entire tank building experience. It provides a lot more details than you will find here, just less well organized. There’s even a bit of humor in it – it was needed. You will find that I had a lot of missteps in my tank building process… steps that caused a painful amount of rework (removing and replacing glass) before I finally got it right.

In that process I learned a lot – from doing it wrong, figuring out why, then doing it right and learning from the change. If I had known then the things I know now, my whole tank building project would have been easier, faster, and cheaper.

*Disclaimer*
All of the information here is specific to building a 75 gallon tank like mine. It worked for me. I believe (but cannot guarantee) that it will work for you too, if you do exactly as I specify here. But if you deviate from what I’m describing here, I suggest you read my thread, talk to people, and do your research first. Good luck!



Why build a tank?
I didn’t want to build a tank – I’m too busy, and didn’t know how. But I did have a few criteria in a tank that I refused to compromise on, so I was left with little choice:

1) A frame-less, rimless, all glass, tank (ADA like)
2) Having cosmetically lovely glass edges and small, very neat, silicone seams. This implies not buying from vendors that do not have a proven and consistent record of providing such tanks.
3) Not spending more than $1000 on a tank, including shipping. Hoping to hit half that.
4) A low iron (clear glass, not green) tank.
5) A non-tempered bottom, to allow bulkhead holes to be drilled.
6) Very small, neat silicone edges (difficult to see).​
All glass tanks of varying quality can be purchased. But within the US the geographic availability varies greatly unless you are willing to bear very large shipping costs.



What will it cost? What do I need?
The glass is the primary expense. If you include bulkhead holes, as I did, that will add cost. I you elect to use normal green “float glass” used in most tanks, you should be able to get the glass from a local glass cutter for less than $200. If you are asking for some variety of ‘low iron”, or clear glass, expect at least double that cost. Probably triple. DO NOT buy tempered glass of any variety.

Tools and consumables constitute the rest of the cost. I don’t remember all of my exact costs, but it was something like this:

60” J Clamps – (6) at $15 each
Cabinet right-angle braces – (2) at $12 each
Acetone – (1) 12 oz. can at $4
Razor blades – (6) boxes of 10 Exacto brand blades at $3
Razor knife – (1) Exacto brand $4
Sand paper – (1) pack #120 grit, $3
Square, or Right-angle, ruler – (1) ruler at $7
Silicone – (4) tubes RTV108 at $9 each, (translucent or black), FYI – you should buy (1) extra 
Caulking gun – (1) at $5
Masking tape – (3) large 2” wide rolls, 3M brand at $5 each, FYI – cheap stuff sticks to the glass​
This totals well over $200 without the glass, more if you have to include shipping and or tax. And that does not include the cost of glass.



Construction Considerations

*Silicone*
All silicones are not created equal. AGA Aquarium silicone is similar to GE Silicone I "window and door", and is made by DOW. It also appears to be the same thing as Perfecto Aquarium silicone. These silicones are only appropriate for aquariums with large seams, something I have little experience with – I started my aquarium with AGA Aquarium silicone and kept popping seams. But then I switched to GE RTV108, which is apparently used by some commercial tank builders. With GE RTV108 you can make very small seams. I gather SCS1200 works very well too, but it is difficult to get your hands on in small volumes. Both of these have a much higher adhesion strength than commercial grade silicone like GE Silicone I or “aquarium” silicones, your typical stuff available to use at Big Al's or Home Depot. These commercial (not professional) silicone have so little adhesion strength the manufacturers don’t even list it in their performance specs.

Bottom line - commercial grade silicones _can _work with big seams, but professional grade silicones _do _work, and with small seams.


*Seams*
There is no need for external seams – all seams are on the inside of the tank. All excess silicone on the outside should be wiped away as a part of the assembly process. Using GE RTV108 silicone, ¼” is sufficiently wide for your interior vertical seams. But on the bottom, where the pressure is greatest, you need to lay down a large 1” seam on the bottom pane with a seam extending ½” up the inside of the vertical glass panes. Or at least that worked for me.


*Glass*
The biggest concern for glass is bowing under pressure, technically called deflection. The amount a piece of glass is going deflect is based on the dimensions of the glass. The most important factor in the pressure that is exerted is the height of the water behind the glass. The most important factor in the amount of bowing it will do is the thickness of the glass. 

I could talk at great length about this, but I will just provide these guidelines instead.

1) If you build a standard 75g tank, 48” wide by 22” high or so, ½” thick glass will work.
2) If you build that same tank, but make the sides only 3/8” wide, that should work.
3) If you build that same tank, but make the long 48” front and back with 3/8” glass, it will probably work, but it will bow so much you’ll wish you never did it. And you’ll be scared to leave it full of water in your house. Or so I am told.​Me, I used ½” glass all the way around, and my deflection is only 1.5mm on both of the large panes. Much more than that, say approaching 3mm, and you need to worry. In my reference sources I link to a number of sites that deal with this, since bowing is probably the most critical consideration in glass aquarium building. Next is the choice of silicone IMO.

When you order your glass, make sure you get a company that can polish the edges with a machine. If they just snap the glass and hand polish it, you will get ugly rippling, wavy lines on the cross sectional surface of the glass. Machine polishing removes this.

Also these same machines can usually bevel the glass for you, which makes for a much nicer looking end product. If you get it, you’ll be happy you did.


*Masking*
Silicone is really, really difficult to remove from glass once cured. So you want to put masking tape over every inch of the glass that is not going to be siliconed. This is going to take a lot of time, and you will find it frustrating. But until you spend hours removing silicone from the glass, you’ll have to take my word for this… it’s worth the time. It also helps protect the glass from scratches in the assembly process.

If you are experienced at applying silicone (you know who you are), you only need to mask edges, rather than the whole glass surface.

No matter what you hear to the contrary, don't pull up masking tape unless the silicone is within minutes of having been applied. After that, it HAS to be fullycured, or you risk ripping the curing silicone up off the glass surface.

When you do remove the masking, after curing is complete, be sure to run your finger along the silicone seam, pressing down just at the spot where the masking tape is pulling away from the glass. This will prevent any silicone on the masking tape from pulling up silicone from the glass as it separates.

Masking example









*Work Area*
You will need to assemble the tank on a raised surface, like a tabletop. Your glass will be very heavy, and bending down to lower the glass to a floor level surface will significantly increase the difficulty of the assembly process. Also raising the glass over waist level will also create problems.

The surface will need to be very, very flat, and very sturdy - vibration free. I assembled mine on a raised redwood outdoor deck, and I’m certain that some of the leaks I sprung during testing (requiring removal , cleaning, and resiliconing of glass) was directly contributed to by assembling on a vibration sensitive, less than flat, surface. 


*Preparation, Planning and Execution*
A lot of work should go into getting ready for assembly. This includes: 

1) Detail discussions and precise, written instructions to the glass cutters. It included allowable tolerances, or variance, in the precision of their glass cutting. Make sure the toloeances you will acccept are in writing. To a company that makes glass for windows or shower doors, a 1/16" variance is pretty good work. To someone trying to make an all glass aquarium, it could be a show stopper. You want variances of 1/32" or smaller.

2) Elaborate edge masking. This even included constructing or finding a small tool to slide along glass edges as a guide for a consistent distance from edges. I found a small cabinate hinge, that when slid along the edge of the glass, it provided just the right distance from the edge for masking.

3) I built a small "throw away" test tank as a learning/practice exercise. I would strongly suggest this to anyone. Learning the basics of assembly and silicone application on hundreds of dollars of glass is a risky learning experience in my opinion. Give the whole thing a try on $30 worth of glass first to see what you are getting yourself into. It gets a lot harder when the glass gets bigger and heavier.

4) Before assemble of any given panel (piece of glass), every step was planned, explicitly written down, and discussed with the people providing assistance. Nothing was rushed or unplanned.

5) Because the actual application of silicone, and preliminary clean up of edges that has to be done very quickly before hand, every step of putting on a glass panel should be practiced immediately prior to actually doing it - sometimes multiple times. This means timing the speed of laying down silicone beads, putting glass in place, attaching clamps, and practicing wiping away excess silicone. When siliconing your actions need to move like clockwork. When you’ve already laid down a bead of silicone, it is no time to figure out you can’t heft a piece of glass, or that a clamp isn’t going to fit, or that an extra tube of silicone is not handy (or the scissors to cut the tip off with!)

6) Time your practice sessions. Laying down silicone and placing the glass in place MUST take less than 5 minutes, and the entire process involving clamping, ensuring everything is square, and wiping away excess must come in under 10 minutes.​

*Clamping*
The clamps you will need will change with each side you build. Apply clamps as follows:

_Backside attached to bottom, no other sides_ -
Use a cabinet right-angle clamp at each end on the bottom to hold the back perpendicular to the bottom, and use two J-clamps to press the side down onto the bottom.

Properly clamped backside









_Attaching the small sides to the bottom and the back_ -
For each of the two sides use a cabinet right-angle clamp to hold the side at right angles to the back. And use two J-clamps to press the side down onto the bottom. And use two more J-clamps to compress the side panel against the back pane

_Attaching the front pane_ -
Use four J-clamps to compress the front pane to each side panel. That’s two J-clamps per side. Also use a cabinet right-angle clamp at each end on the top to hold the front perpendicular to each side, and use two J-clamps to press the front down onto the bottom.

Example of HOW NOT(!) to attach the front pane








I had to replace this pane because of I used an orange strap clamp (see it around the top?) instead of spending the extra money to get the two more J-clamps I should have used to press the top of the front to the top of the sides. In this shot you can also see how the cabinate clamps are used to keep the top square with the sides.

And here is that same front side being reattached - clamped correctly this time










Tightness appears to be critically important in clamping. Don’t use strap clamps – they cannot exert enough pressure. I wish I could provide clear guidance on how hard to crank down on the J-clamps. But about all I can say is that they need to be tight - nice and snug. Or just a bit of effort beyond what is referred to as “finger tight”. But if you really crank down on the clamp you will squeeze out ALL the silicone, and that can be almost as bad as not tight enough.


*Assembly*
When putting the panes of glass on you will want to do the following to ensure you get a good seal between the panes of glass. And by “good” that means sturdy and bubble free. 

1) Use LOTS of acetone to clean every surface to be siliconed immediately prior to laying down the silicone beads. How much is lots? If it is dripping silicone, that should be enough. Use a lint free cloth and a bit of elbow grease to clean the wetted surface, and a dry lint free cloth to mop up the excess acetone. Give it a minute or two to evaporate.

2) Squeeze large, wide beads of silicone on the glass – lots of excess. If you use an entire tube of silicone for one large 48”x22” piece of glass, you’ve only used just a little too much. If you only used ½ a tube for a large piece of glass, use more next time. The key is to lay down excess silicone and so that you have to wipe up big gobs of excess after the glass is in place.

3) When you set a pane down on the bottom piece of glass, set it down at about a 25 degree angle, and sloooowly tilt it up to avertical position.​In terms of order of assembling panes, use the following considerations.

1) The bottom goes down on the work surface; everything will be built on top of that.

2) Only one piece of glass goes up at a time, two days between each of the four vertical panes of glass. Longer if the humidity is very low.

3) Start with the piece of glass that is going to be the long backside of the tank first. Then two days later, apply a side, then the other, and finally finish up by putting on the front.

4) For every place where a vertical pane rests on the bottom pane, apply the silicone for the bottom seam to the bottom pane, not the vertical pane.

5) For all vertical seams, place the vertical seam on the pane being applied, not on a pane already on the tank. This seems to reduce bubbles in the silicone. I don’t know why.​
Once a pane is in place, one person needs to gently hold the glass in place (the silicone will help) and put one or two clamps on loosely. Then use your square to make sure everything is at 90 degree angles, gently making adjustments as required. Then put on the rest of the clamps, "finger tight" only. Once all clamps are on, tighten them down, alternating sides (first tighten a clamp on one side, then one on the other – back and forth) until done.

Once all clamps are on, begin wiping away excess silicone. If you have masked properly your thumb should work great to push away the excess. Have someone standing by with paper towels to clean your thump off often (there will be a lot of excess silicone). A waste basket will need to be near by to drop in the messy paper towels.

For the huge bottom inside seam on each pane, go ahead and treat it like all the other seams, wiping away the excess. Once all seams have had their excess removed, then go in and lay down a big bead again on the inside edge of the bottom. Yes, I know the little seam may have “skinned over”. That’s OK. Silicone sticks great to silicone, so the stuff you are squirting on top if it will bond well with the original seam. Then do the best you can to smooth out the excess silicone on the new big seam with your thumb – paper towels at the ready.

I’m told that by wetting your thumb with water that it makes a nicer seam, and the silicone is less inclined to stick to your thumb. You can try it, but it didn’t work for me.



Lessons Learned

What _can_ happen








This unfortunate shot was made possible by several factors:

 Making small seams with commercial grade silicon. Making tiny seams safely requires professional grade silicon.
 Inadequate claming - didn't use enough clamps.
 Tesing on a vibration prone surface.
 No styrofoam underneath the tank.
You shouldn't have to repeat my mistakes - you can from them instead, just as I did.

*Glass removal*
If you do have to remove a glass pane for replacement, use an Exacto blade to cut it away. But if the seam is too small for that, don't try to wedge an Exacto in there. It scratches the glass, and can even chip it - I know. A very thin piece of steel wire works much better. You can find this in a hardware store for hanging picture frames.


*Removing silicone from glass*
1) If you have to remove cured silicone from a pane of glass, be prepared to spend many hours getting it perfectly clean, 8-12 hours for a large pane of glass – or only ½ that if you have a Dremmel.

2) Use a razor blades to get up a much as possible. Change blades VERY often, and keep scraping with a sharp blade until nothing is left but a silicone film.

3) Then use acetone and dust free cloths to rub away that fim. But that can take hours.

4) To dramatically reduce the time in removing the silicone film left over after the scraping, use a Dremmel tool (if you are lucky enough to have one) with a felt polishing pad. 

5) The dust and film residue left over after the Dremmeling comes up real easy with mineral spirits, followed by a quick hit with the acetone, and you've got marvelously clean glass, at minimal effort.

6) If you are trying to get that residue film up, and don’t have a Dremmel, don’t waste your money on "Greased Lightening", "Dirtex", "De-Solv-it", or "Goof Off". None of it works as well as Acetone and elbow grease.

7) Also, be warned – If you spend enough hours with a razor blade in your hand, you are going to cut yourself. Count on it.


*Removing masking tape*
The longer masking take stays on glass; the harder it is to get it to come off clean. And expensive masking tape comes off cleaner than cheap masking tape.


*Curing the silicone before filling*
Curing time improves substantially in high humidity, and reduces in low humidity. At 50% humidity, I would advise waiting 5 days after I laid down my last seam before filling the tank.

If the seams feel hard to the touch, meaning you can't leaves a finger nail impression easily, then you should be able to add a bit of water. Fill it with about 1/8" inch of water in the bottom and the humidity will help it cure faster. 

And if there are any questions about whether your tank is cured, smell the thickest and/or newest silicone. If you can detect that vinegar-like smell (at all), it’s not cured.


*Assembly time*
If you allow a silicone bead that goes between two pieces of glass to “skin over”, or form a slight film on its surface before you press the glass together, you should prepare for that seam to fail under pressure. Generally that means that you MUST press the glass in place within a few minutes of laying down the silicone bead. IMO 2 minutes is safe for the professional grade silicons I reccomended earlier, 5 minutes for commercial grades. Any longer and you are accepting an element of risk.


*Filling and Testing*
I believe you MUST have a piece of Styrofoam under your tank. And that your tank must be on a flat, level, vibration free surface.


*Moving the Tank*
Having two full grown, level headed, strong people to do the lifting and moving of the tank is a piece of cake. Having a wife and kids help you move it, as I did on occasion, is just begging for trouble. Your tank will be both fragile and quite heavy.


*How long until I know it won't leak?*
I don't know, maybe 10 years? :icon_wink But I do know that in my learning experience I sprung multiple leaks (from my mistakes). Almost every one happened with 24 hours. The one exception happened after 5 days. But that was because I had the tank on a vibration prone deck, and the night it sprung a leak we were running back and forth to across the deck. I believe that was more of a stress induced leak, caused by unstable flooring and inadequate padding under the tank. In a vibration free, correctly padded setting that tank would have never sprung a leak IMO.
In conclusion - 24 hours is the magic number. Butif you are paranoid (like me) leave it full for 7 days before you really trust it.



Ephemera

*Tank Setup*
Keep in mind, your tank is not reinforced. It’s just held together by silicone. So if you are using shims to level your stand, you are going to have to do it gradually and gently. Start with an empty tank, then adjust when ¼ full, then at ½ full. Get it perfect at that point. Jarring your stand around after that just puts too much stress on the tank IMO.

Make sure you really level your tank very well, especially side to side. Since there is no rim at the top to hide a small tilt of the tank. Any tiny amount of tilt will be quite noticeable – especially if it is side to side. Front to back level problems are a little less noticeable. 


*More information on silicone*
I spent an hour an hour on the phone with an industrial application silicone guru at GE, and got the real low down on silicone. Here are some fun facts from that call:

1) No manufacturer will tell you their silicone works underwater, since they all degrade underwater over time. Only someone OEM'ing silicone will make that claim.

2) Silicone's primary strength is to itself, not what it is bonded too. So if it starts to pull away in a spot in an aquarium, it is almost certainly not going to "snap" with the tension, creating only a small leak. It will hold together in one piece and if more pressure is applied will continue to tear away from the glass instead, creating a potentially catastrophic leak instead.

3) GE’s SCS1200 has their highest adhesion strength, twice that of their commercial grades, and an unspecified amount over their consumer grades.

4) Silicone's adhesion strength in general does not approach its tensile strength. If you lay down a bead on top of some glass, you will be able to pull it up much easier than getting it to snap while pulling it.

5) The aquarium application requires silicones weakest strength, adhesion. This explains why all tank manufacturers all lay down a nice wide seam along the bottom edges of the tank. That's not just to fight water pressure, that's also to provide more adhesion surface to keep the bottom edges from ripping apart.

6) Silicone bonds very well to silicone, but much less well to anything else... like glass.

7) SCS1200 will only cure to a 1/4" depth. So under 1/2" thick glass, there can be no excess on either side while it cures. And that is 5 days at 50% humidity - more days if the humidity is lower.​

*The Problem with Bottom Bulkheads*
I built tank with bulkhead holes in the bottom to facilitate water flowing into/out of the tank without visible equipment. While I know that will not affect most people, I thought it was worth passing along some of the consequences of that decision.

1) Everyone makes tanks with tempered glass bottoms, so bottom bulkheads almost certainly mandates custom tank building for many tank sizes.

2) The hardware adds cost

3) Having the holes drilled can add very significant cost. Or if you drill them yourself, significant risk.

4) I'm told it destroys the resale value of the tank.

5) Any padding, or support (Styrofoam, boards) under the tank have to have matching holes cut and/or drilled. So getting a new board is a PITA.

6) The hardware takes a lot of space under the tank that must be accommodated. In my case, it also meant that I had to remove the drawers from the stand (drawers would have been nice).

7) They limit aquascaping options. You've got equipment to hide. But more holes increases your flexibility.

8) You significantly increase your opportunities for leaks.

9) Moving your tank involves a potentially non-trivial disassembly process. It's not as imple as drain the water, pull out the hoses and move.​
And for everyone of these factors, except for #1 and #7, it gets worse in direct relation to the number of bulkhead holes you have.


*Bottom Bulkhead Lessons Learned*
1) Install the bulkheads before you put the tank in the stand. Much easier! 4"x4" posts work well as supports for the tank so you can work above it and have room below for tightening the bulkheads.

2) Plastic bulkheads can break if over tightened. And since they have to be very tight, you don’t know how tight “too tight” is until you break one. Having 1 extra bulkhead around can be a lifesaver if that happens. 


*Personal Perspective*
Lot's of people build tanks like this all the time. And for them I'm sure this is pretty easy. But without very proscriptive instructions, I found this to be a bit difficult and daunting. But certainly possible, and immensely satisfying once complete.

My advice is to be constantly aware of the danger - even professonal glass fabricators don't like handling such heavy untempered glass. One small slip, with a piece of glass breaking the wrong way and a bit clumsy handling could lead to very serious injury, or even death. Be careful.

I also advise humor and perseverance. If you are doing this for the first time, it may not go exactly as you expect. Expect the unexpected. And don't give up if you have to spend a bit more time on your construction project than you anticipated. But hang in there. Keep your sense of humor at the ready, and you'll have something beautiful that you can be proud of before you know it.:icon_wink 











Reference Sources
My best information sources were Tom Barr of The Barr Report, and Del Goins of AquariumPlant.com.

But I got lots and lots of really good advice from my friends at PlantedTank.net. Thanks folks! I could not have done this without you.

Also the following internet sites were quite useful.

http://www.colley.org/images/Selection Guide for Glass in Furniture New.doc

http://saltaquarium.about.com/cs/aquariumdiy/l/blcustomtank.htm

http://saltaquarium.about.com/cs/aquariumdiy/a/aa120897diyaq.htm

http://www.fnzas.org.nz/articles/technical/glassthickness/


----------



## scolley

OK, I left this up for a couple of weeks while I finished off the draft. So now it's finished, though I got no comments for change... so I assume it was either OK, or of no interest.

I can certainly see how someone might be hesitant to try this. But after everything I learned, it seemed a shame not to write it up for the community.

So, just in case someone out there might like to try this themselves, here's the first submission of how to build a 75g all glass tank.

As always, I'm interested in your feedback.:icon_wink


----------



## Hoppy

Fascinating article! Thanks for posting it. The primary emotion it causes me is fear! If I tried that and had that tank in my living room, which is on the second floor, I would soon have gray hair - even white hair! But, you did a really beautiful job.


----------



## scolley

Thanks Hoppy. I'm wondering it this might have more value if it were not an article based on the primary learning experience (i.e. - all the leaks), but were instead an article based on a 2nd tank - one where I applied all the things I learned the first time around. Hopefully with a completely leak free conclusion.

I think a 2nd attempt would indeed be completely leak free, now that I know what to do.

Anybody near here wanna build a nice glass tank?


----------



## Solace

All I can say is that not having rimms on it scares the living daylights out of me. I am going to be moving here in a few years and hopefully wil have a place in which I can setup a large 90-120g tank, but im not sure if I am comfortable with not having rims on it. Granted it would be nice to have a rimmed tank with very small tight silicon seals I am thinking of maybe having the rims custom made of stainless steel, with maybe a minor gold inlay in places. 

I just cant see the ability of the silicon seals holding up to the stress of the water pressure, i dont get the math on it.

Needless to say, it is a very nice looking piece of art for any room!


----------



## Green_is_beautiful

I agree with Hoppy - your article has seriously turned me away from ever even thinking about building a tank like that (my hair colour was changing while i was reading ). NO - thats not a bad thing (making me think about building a tank - not my hair). 
It wouldn't be in my budget anyways.

It was well written though and contains a lot of great information !! Well done.

Now i don't want to take away from this great article by asking a (somewhat) unrelated question. (if it appears that way i'll delete this post later) 
But I thought i ask in here because obviously you really did your homework when i comes to silicone.

Whenever people talk about reapplying silicone in old tanks that developed a leak - they mention that you cant just cut out one seam (the leaky one) and reapply silicone there - you have to redo the whole tank. It's because (supposably) old silicone doesnt stick well to new - and you just end up having a leak where the old meets the new.
Now you obviuously did the opposite - working on a seperate panel every 2 days (or more if humidity was lower). Basically having new+cured silicone meeting in a lot of areas.
Going from your experience with silicone - is it really necessary to redo the whole tank if you have a leak somewhere ?
Thanks. (P.S.: My native language isn't english so excuse it if my post is unnecessarily lengthy cause i am sometimes not able to get to the point as quickly)


----------



## scolley

Green_is_beautiful said:


> Whenever people talk about reapplying silicone in old tanks that developed a leak - they mention that you cant just cut out one seam (the leaky one) and reapply silicone there - you have to redo the whole tank. It's because (supposably) old silicone doesnt stick well to new - and you just end up having a leak where the old meets the new.
> Now you obviuously did the opposite - working on a seperate panel every 2 days (or more if humidity was lower). Basically having new+cured silicone meeting in a lot of areas.
> Going from your experience with silicone - is it really necessary to redo the whole tank if you have a leak somewhere ?


Well, I've gotten it from the experts that silicon sticks to silicon very, very well. But maybe they meant fresh silicon, not aged silicon. I also got it from the experts that no silicon manufacturer makes silicon that they will say works for aquariums. Other companies buy the manufacturers' silicone, who then repackage it, and call it "aquarium" silicon. But the manufacturers _know_ that silicon breaks down underwater, and does so much faster than silicon that is just exposed to air.

So they take the conservative position and will not warrant that it will work underwater - its life it too limited in that application. So maybe that is why, when a tank springs a leak that you redo the whole thing - you take that as an indicator that it is all breaking down, with this as just the first warning sign. Sounds good to me.

As to the fresh stuff sticking... well I sprung a LOT of leaks before everything was OK, but I never sprung one at at point where I joined cured (or semi-cured) silicon to fresh. So I trust the advice of the experts on that - silicon sticks to silicon. Or at least it does if it is not old silicon.



Solace said:


> just cant see the ability of the silicon seals holding up to the stress of the water pressure, i dont get the math on it.


I don't do much math at all myself. :hihi: But I can tell you silicon is amazingly strong. But its strength is is primarily tensile. It is weak with adhesion, which is exactly what you need most for an aquarium - you need it to not rip away from the glass. That's why the commercial stuff fails if your seams are not large. The professional grade stuff is substantially stronger in adhesion strength. Most people's experience with silicon, and I suspect the experience you are drawing your reasonable observations from, is commercial silicon.

The stuff I'm recommending is something entirely different - much, _much _stronger.


----------



## Sietch31

Hi Steve,

I've missed that one thread....(and probably one or two post in the other monsters threads  )

But all I can say is that since you started, in my crazy mind is turning the idea of making one big frameless tank....

So all this is of great help for me, thanks !

I have determined the ideal dimensions of tank.
Ideally that would be 140/55/65 cms (roughly 55/22/26 in) ie 500 liters (132 gal)
It is big I know but my aim is to have a frameless tank, planted, open top and to host some Pterophyllum Altums in it :fish: 
Hence the big dimensions....

I am in the process of calculating glass thickness but cannot find documentation specifically for frameless tanks....
Where did you get that from ?

For the glass I think that crystal clear glass will not be available here unfortunately.... 
I'll keep that for the tank I'll build when back home  

For the silicone, your research are of great help, and again I am afraid I will not be able to find that professional grade here, so I will have to get it shipped either from Europe or the US.
Where did you get yours ?
Do you know if they will ship overseas ?

For construction, there are here a lot of little tank makers that are very cheap (man hours are not the same rate here compared to Europe or US :icon_mrgr ).
So my plan is to order the tank to one of them I know (he already made one small 140 l framelless tank for me) and providing him the right silicone, as well as assisting him during the assembly to make sure we will follow all of your advices...

What is still not decided:
- Black or clear silicone ?
- Canister filter or sump ? (although I already own a 2026 but need a second one for such a volume)
- Drilled bottom or not ? (although I must admit your idea of not seeing the equipment is really tempting me)
- Negociation with Home Prime Minister still underway :hihi: 

Any input/advice from your Highness will be very much appreciated :icon_mrgr !!!

Sorry for being so long, you know what I mean.... 

Sietch


----------



## scolley

Sietch - If you are talking about a 55cm high tank, your long sides (front and back) need to be 12mm, if you height dimension is 65cm, you need something bigger - maybe 14mm. Take a look in here . It's all there on the last page.

Having done clear silicone now, if I were doing very small seams all the way around (I would), next time I think I'd go for black silicone. I think. It doesn't show algae as well.

I don't remember where I got mine. Google it. But www.grainger.com and www.hmcelectronics.com both carry it. Don't know where they will ship though.

As for the bulkheads vs. not, canister vs. sump, I'd rather not get into those questions too far in this thread - a good search here will yield a lot of thought on that. But suffice to say, next time I'm going to be looking at a normal sump setup real hard. I've personally tanken in-line about as far as it can go, and sumps seem a lot easier. And drilling bulkheads massively complicated the build and test process. You'd have to read my thread for evidence of that.

Good luck with the PM.


----------



## Breadman

Steve,

I must say that I am very impressed with you tank, and instead of being scared away as some others have been it has encouraged me to go ahead and start my own tank. I just left the glass shop after placing my order for some glass for a test tank (12"x12"x12") and I have found a local supplier of the RTV108.

One of the things that prompted me to attempt to build my own tank, besides the ugly black rim on the top and bottom, it the wide silicone seam on the tanks. I really hate the way this looks on a tank. Would it be possible for you to post a couple of close up pictures of the side and bottoms seams of your tank?

Thanks for the great insperation, and taking the time to share this with everyone here.


----------



## scolley

Thank Jim. I'd be happy to. Before I do that, let me explain what I'll be taking pictures of, and why...

1) A front vertical seam - these were the ones where I used the RTV108. If you read my excruciating thread, you will know that I did not use RTV108 all the way around - just on the front pane. It kept on leaking, and leaking, and leaking. Which caused me to do my silicon homework, but I did not replace every pane - just the front that was leaking. So that was the only pane with the RTV108 - But the vertical seams are very small.

2) A back vertical seam - these were plain old aquarium silicone. I'll give you as shot at the seam just so you can see the successful size difference - larger.

3) A side bottom seam - again just plain old aquarium silicon. But it is dramatically smaller than the front seam. Why? Because there is less stress on the shorter side bottoms than the longer front and back bottoms. And because I went wild with the front bottom seam, as explained below. 

4) The front bottom seam - as with the front vertical, it's RTV108. The entire front is. But the difference here is the seam size. I had problems with the bottom - multiple times - and I was just fed up with fixing leaks (hours and hours of work). So I laid down a massive front seam. Since it is RTV108, it is probably way, way bigger than it needs to be. The other bottom seams of plain aquarium silicone are smaller. Problem is - I can't prove smaller is OK. So rather than mislead you with what I _think_, I'll show you what I _know_ - which is that this big mother of all bottom seams works.​
I'll try to get to some pictures soon.


----------



## Sietch31

Hi Steve,

Thanks for your links : i just found that Grainger has a subsidiary in Dubai !!!
Great !

One question (again....) : how many tubes of silicone did you used for your tank ?

Sietch


----------



## scolley

4 big calk gun sized tubes - but I'd buy 5 just in case. Running out of silicone, and having to order more, is a drag!

Been there, done that I'm afraid! If you find that by not messing up, and not having to replace leaking panes (everything works right the first time!) takes less tubes, please let everyone know by posting that here. Thanks.


----------



## Sietch31

Thank you very much !

I will give you some updates as my project will progress....

Sietch


----------



## scolley

*seam pics*

Well, I went to take seam pics and I found things were not quite as I recalled... so you will find these pics aren't exactly as I previously said they would be. So much for having a decent memory.:hihi: Also, because of where my aquarium is located in the room, with a wall against the back and the left side, and with another aquarium by its right side, my camera angles were limited.


Here is a front seam - left front actually. This is looking at the tank from the front. The front pane of glass extends all the way to the far left and right. The side panes are behind this front pane. So this seam is where a side pane attaches to the front. This is RTV108 silicone.










This is the opposite corner - the right front corner. But this is a view from the right side of the tank. The thick glass on the left is the front up against the right side that this shot faces head on. That silicone is also RTV108.










Now THIS is the same right side, but showing the seam of the back pane instead. Now the wild thing is, this is clearly a small seam too, and it is NOT RTV108 but regular aquarium silicon I believe. So I suppose this demonstrates that even though I had a LOT of leaks with regular aquarium silicon, some seams can be small and still not leak.










And now here is the mother of all bottom seams. This is the front pane, which sits on top of the bottom pane. The bottom pane is not visible because it's hidden by the wood trim on the my stand. It's RTV108 and it's HUGE because I just got sick of the bottom leaking and decided to stop messing around with little bottom seams. It is massive overkill I'm sure, and a bad example, but you gotta read my thread to understand that by the time I laid this one down, I had about had it. So this is the "never gonna leak again in a million years" seam.










And finally here is a shot of the tank itself, so you can get an idea of the size of the seams when looking at the tank.










So much for seam pics. I hope that helps.:smile:

Oh yeah - one other thing... in the bottom pic you can see why next time I might go black in stead of translucent. Since you can still see the seam, and since it is an algae magnet, why not just make it black. The edges of the tank have kind of a natural darker boarder due to the color of the edges of the glass on the sides. I think a skinny black seam might blend in better with that natural dark blue border than the bright whitish - maybe be mess noticeable. My two cents...


----------



## Anti-Pjerrot

wow - nice work. 

Im planning to do a polycarbonate tank soon, 2,1gal nano :wink: so not much work there - but the tips u got a great. Thanks.:thumbsup:


----------



## scolley

Anti-Pjerrot said:


> wow - nice work.
> 
> Im planning to do a polycarbonate tank soon, 2,1gal nano :wink: so not much work there - but the tips u got a great. Thanks.:thumbsup:


Thanks. For anyone thinking about something similar... it's all in the masking! Invest the hours of painstaking masking work, and you'll get years of a great looking tank in return.

Good luck with the polycarbonate! I hope we will see some details on that.


----------



## Anti-Pjerrot

> it's all in the masking!


Thats possibly the best advice I can ever get. :thumbsup:


----------



## Hoppy

How do you glue polycarbonate? Does it use a solvent glue so it welds the seams, or a stickum adhesive like silicone?


----------



## csf

I made a 10" cube poly tank. You use a solvent welder. You basically build the tank with lots and lots of tape (masking and electrical) to hold things together and tokeep the sides clean and then you run a bead around all of the internal corners.

At that point the solvent "spreads" to weld the entire seam. But once it gets "wet" don't move it. Check garf (.org I think). They have a tank builder helper for both glass and acrylic tanks. I also didn't use their framing pieces and have had no issues w/ bowing (but it's only a 10" tank).


----------



## Hoppy

Acrylic is cemented with solvent, and it actually welds the material together, but I don't know if polycarbonate, a different plastic, is welded the same way. That's why I asked. I've never seen anything about cementing polycarbonate.


----------



## wendle

hi scolley, your tank came up really nice, but i have to say you did quite a few things to make it a lot harder for yourself than it needed to be 

i have built a lot of big aquariums and done a lot of commercial glazing and showcase work, so i would like to offer a few tip to the people reading this. but i don't want to critisize your work as your end product turned out great.

the first thing i noticed is that you put the bottom of the tank on the bottom, under the front/back and ends. the easiest way to build the tank is to put the bottom inside the front, back and ends. that way you can lay out all your panes, run the silicon onto the face of the joint surfaces, and then just stand them up.
also, you aren't doing yourself any favours by clamping the whole thing up tight. the strongest way to produce a silcon seam is to have a 1 to1.5mm gap between the glass surfaces, the gives the join flexibility without having to worry about tearing a thin membrane of silicone away from the glass.
i lay the panes out, apply the bead of silicon to the joint surfaces, stand up one end and one face and push them together with hand pressure (big tanks take two or three people to stand these first two panes up) then stand up the other end and the last face, just squeeze the whole lot lightly together with hand pressure, making there is no less than 1mm of silicon seam at the visible joints. obviously you can't see the seams along the bottom, but if your cutting is accurate, this won't be a problem. i then wet my finger and run it around the bottom joints only to smooth in the squeeze-out. then walk away from the tank and don't touch it for a week. the vertical seems don't need to have the squeeze-out flattened out. it can just be sliced off with a razor blade when it has cured. 

i don't mask ANYTHING up, and this is why: assembling the tank as per above means you shouldn't have any excess silicon anywhere, the time between applying the silicon and walking away from the tank is only a couple of minutes. the only time you should get any silicon on your hands if when you run your finger around the bottom, and as soon as you do that you should be walking away from the tank and forgetting about it.

for a tank with lids and braces across the top, i just glue a long rib to the front and back of the tank a day before i assemble the tank. after the tank has cured for a couple days i will then glue the braces across it.

a flat surface is very important for assembly, there is no problem with doing it on the ground with this method as you'll only be kneeling down for a few minutes and then it will be all over, but it has to be flat. thick formwork ply or thick MDF/chipboard work well, as long as they are nice, new, flat sheets.
i put newspaper down under the bottom so the tank doesn't end up glued to the work surface, you can then just cut the paper away when the glue has dried.

cliff notes: fit the base inside the faces, no clamps, no messy fingers/tools, no worries!


----------



## scolley

Hey Wendle, where the h*ll were you when I needed you!!!!:hihi: It's a little late for all the good advice now!

Just kidding. 

I'm thrilled to have you post here. Thanks!


The whole point of my putting anything up at all is to spread the knowledge. If you can top mine, by all means please do! Better for everyone!

I'm not sure why I assembled the bottom across all the panes. There was some process of evaluation based on internet available information, and that was my conclusion. But I can certainly see a great benefit in what you are suggesting. Not the least of which having to buy fewer tools, and just being easier. The way I did it was a PITA.

I'm curious about the trimming... do you mean that you just trim the inside seams flush with the edge, so there really is no seam, other that what is between the glass?

Also, what size tanks have you constructed like this? And can you offer additional insight into appropriate thicknesses?

Thanks a mil' for posting Wendle. Can't wait to hear more!


----------



## wendle

scolley said:


> Hey Wendle, where the h*ll were you when I needed you!!!!:hihi: It's a little late for all the good advice now!
> 
> Just kidding.
> 
> I'm thrilled to have you post here. Thanks!
> 
> 
> The whole point of my putting anything up at all is to spread the knowledge. If you can top mine, by all means please do! Better for everyone!
> 
> I'm not sure why I assembled the bottom across all the panes. There was some process of evaluation based on internet available information, and that was my conclusion. But I can certainly see a great benefit in what you are suggesting. Not the least of which having to buy fewer tools, and just being easier. The way I did it was a PITA.
> 
> I'm curious about the trimming... do you mean that you just trim the inside seams flush with the edge, so there really is no seam, other that what is between the glass?
> 
> Also, what size tanks have you constructed like this? And can you offer additional insight into appropriate thicknesses?
> 
> Thanks a mil' for posting Wendle. Can't wait to hear more!



putting the base inside just makes things sooo much paster and neater, especially when building a lot of small tanks at once, back in the day i would build 20 or 30 (!) standard 2ft or 3ft tanks for pet shops all in one hit. you have to be fast, tidy and organised to pull that off  i would hate to have to try it with the bases sitting under the faces, pretty frustrating. the way i do it there is no need to clamp anything. occasionally if i am building a very large tank with no-one to help, i'll tape the first corner together to stop things moving around. once the whole thing is together, the suction produced by the seams will never, ever, let a pane move.

as far as trimming the vertical seams, on tanks built from 10mm (3/8") or thicker, i cut all the excess off. i use dow corning V2 sealant, which also comes in black whick looks really nice sometimes on tanks made from 15mm or 18mm glass. i must say though on small tanks made from thin 4mm or 5mm glass i am not confident with leaving the corners frameless and exposed as one small knock can shell the glass and crack the tank, so on those i use a small plastic angle on the outside and flatten the squeezeout on the inside same as i always do for the bottom seam.

biggest tank i have built was 8" x 3" x 4" (high) it was a beautiful tank in 18mm glass fitted into some really nice joinery..

as far as thickness, for tanks with braces across the top, i work on 10mm for 700mm high, 12mm for 900mm high, 15mm for 1000mm high, and 18mm for anyhting over that. anything without braces on the top, like yours, really needs special consideration and goes up at least one glass thickness.


----------



## Hoppy

One thing that deterred me from trying to build a tank was the difficulty in getting pieces of glass cut as accurately as I felt would be needed. Do you cut your own pieces, or buy them from a place that is able to precision cut them for you? Does the one mm gap for silicone give you a bigger tolerance on the cut sizes?


----------



## scolley

Hoppy said:


> Does the one mm gap for silicone give you a bigger tolerance on the cut sizes?


I had to accommodate for silicone gaps, as you can see in these pics I gave to the glass cutters.




























But if you are doing it Wendle's way, I would think that would be unnecessary.





wendle said:


> as far as thickness, for tanks with braces across the top, i work on 10mm for 700mm high, 12mm for 900mm high, 15mm for 1000mm high, and 18mm for anything over that. anything without braces on the top, like yours, really needs special consideration and goes up at least one glass thickness.


Thanks! That's great practical advice for sizing. And consistent with my findings... width matters a bit, but at the end of the day, your thickness decisions are really driven by the tank height.

Also thanks for the tip on the Dow Corning V2 sealant! Gotta see if they make that in the states.

Wow! Now I want to try this out on another tank! Could be a lot easier this time...


----------



## wendle

that's another advantage of putting the base inside the faces, you cut one long split for the tank depth and dock it to length for the base and ends, makes accuracy a lot easier. 
cheapest/easiest way to deal with glass is to buy "splits" off a wholesaler. they are basically long rips off a full sheet, the width of which should be one of the dimensions you need, so you are only cutting in one axis for most of your parts.
hope that makes sense?

if you are going to be cutting a lot of glass, get yourself a speed cutter like this one: (hope pic works)


----------



## wendle

one other thing i forgot to mention.
when you are applying your silicone to the faces of the glass, don't drag the nozzle along the glass. cut the nozzle so the goop comes out at the same thickness as the glass, then hold the nozzle about an inch off the surface and keep moving at the right speed so the silicone hangs down and keeps laying onto the glass in a nice consistent worm. dragging the nozzle along the surface always leaves air bubbles in the glueline (which look terrible if you are building a bare-glass tank) and can't be good for strength. 
the nozzles are also made from a nylon that silicon doesn't stick to (for obvious reasons) so you don't want any residue of that particular plastic abrading onto the glass from dragging the nozzle along.
this is probably the part of building aquaria that takes the most practice.


----------



## scolley

wendle said:


> when you are applying your silicone to the faces of the glass, don't drag the nozzle along the glass. cut the nozzle so the goop comes out at the same thickness as the glass, then hold the nozzle about an inch off the surface and keep moving at the right speed so the silicone hangs down and keeps laying onto the glass in a nice consistent worm. dragging the nozzle along the surface always leaves air bubbles in the glueline.


Thanks Wendle! Those bubbles gave me fits! That's the reason why I recommended using so much silicone because the only time I didn't have bubbles way when I was using tons of it.

But in retrospect I'll wager it was exactly as you are suggesting here... it's not that I was laying down more silicone _per se_, but that I was laying a bead at least the width of the thickness of the glass! Which when compressed, of course extrudes a lot of excess silicone.

Not dragging the tip is some great insight too.:thumbsup: 

Thanks!


----------



## Hoppy

How do you handle the weight of a large tank like this? Just the thought of trying to move it without breaking it while gluing it together, cleaning up the excess glue, cleaning the outside, etc. just scares me.


----------



## MoonFish

Wendle, wow bubbles drove me nuts too. I thought scolley's tank would leak when I saw all the bubbles in his picture. I did one that had bubbles and had to redo it about a year later.


----------



## wendle

Hoppy said:


> How do you handle the weight of a large tank like this? Just the thought of trying to move it without breaking it while gluing it together, cleaning up the excess glue, cleaning the outside, etc. just scares me.


you don't move it at all when you are assembling it. where you lay the base down is where the tank gets built and it doesn't move then untill the silicone has at least partially cured. they are very strong then, the only way to damage an empty tank is to drop it, or bang it against something hard. first thing i usually do when they are ready to move is stand them up on one end to pull all the newspaper off the bottom. most tank shapes take up a lot less room that way, and if you stand them up on a peice of carpet you can use that to drag them out of the way so you can start building the next one


----------



## Hoppy

Fascinating discussion! I'll bet a lot of new tanks are either being home built or people are seriously contemplating doing so as a result of this.


----------



## Anti-Pjerrot

Im putting my tank(s) up today - with some advice from both scottey and wendle. 

http://www.plantedtank.net/forums/diy/28638-building-nano-plans-2.html

Im doing it the way wendle does, but im sticking with some masking, because i want slim silicone seams.

I got 4 mm glass - so the hole thing shouldent be a problem, since its fairly easy to work with... Only 2.1 gal

How long should i wait before testing for leaks?


----------



## Big Bob

Hello
How did you go about fiting the "bulk heads" in the bottom of your tank?
Thanx
Bob


----------



## scolley

Anti-Pjerrot - I'd say wait at least 48 hours after your last seam is made. That's if it is curing in at least 50% humidity. Otherwise, wait a just one day and then put some water in the bottom of the tank (1" or 2") to help raise the humidity in the tank. No firm answers here that I know (maybe someone else does???) but if the humidity is lower, you need to wait longer.

Bob Bob - for bulkheads just make sure you have non-tempered glass for the bottom (as with the sides), and have holes drilled by the glass cutters. You can do it yourself if you buy an expensive diamond glass bit and drill it. But I chose not to risk that.

Then you just go to any saltwater aquarium store (on-line!) and get a bulkhead kit. It will have all the plastic parts you need in a single kit to screw on a fitting that has attachments on the inside and outside. The decision you have to make before you buy the kit is do you want slip or threaded fittings - making that decision for both inside and outside. I got threaded for both myself.


----------



## Sietch31

Hi all !

I glued yesterday evening my big tang, following Scolley's and Wendle's advices  !

The tank is 136x59x57 (cm) or for you american friends 53x23x22"
Glass thickness 12.5mm (1/2 inch)
Polished and beveled edges.
No braces (at least until I fill it and measure deflection of front and back panels.....will see)

Following Scolley's advice I used a LOT of acetone to clean...
Following my own wish to make final cleaning more difficult I didn't mask anything... :hihi: 
Following Wendle's advice, the bottom panel is inside the front/back/sides panels.
I smoothened the bottom seals with wet finger.
I made the vertical seams very small with a credit card (expired  )
I used 3 silicone tubes of 310 ml (I had bought 8, just in case...:icon_roll )
All in all, the process took less than 45 minutes...
It seemed to me very easy to do it like that ( it was my first DIY tank).

I will post pictures as soon as I get my DSL connection back :icon_evil 
I will update on watertightness after 3 or 4 weeks as I am going on leave, I guess silicone will have enough time to cure :thumbsup: 

Thank you all for sharing your experiences, that helped me a lot....

Now the adventure begins !

Sietch


----------



## scolley

Sietch31 said:


> I made the vertical seams very small with a credit card (expired  )


Hey, now that's a good idea!

Let us know if it hold water. And good luck!


----------



## Sietch31

scolley said:


> Let us know if it hold water. And good luck!


Well, it does :bounce: 

And for one week now !

Pictures can be seen here:
http://www.plantedtank.net/forums/diy/33620-sietchs-rimless-122g.html

Some more details:

The tank is 136x59.5x57 (cm) or for you american friends 53x23x22"
Glass thickness 12mm (1/2 inch)
Polished and beveled edges.

*Deflection:*
After filling, measured deflection (using same method as Scolley with a ruller sitting on the top edges but longer the the width of tank :icon_wink ) at the top centre is 5mm total, i.e. 2.5mm per panel (front & back)
According to StGobain website and calculation page (I can post link but it's all in french an full of mathematics formulas :icon_roll ) it is acceptable.

*Silicone:*
I bought it from a aquarium specialized french web-store (www.europeen-trading.com), as only standard grade was available in the UAE.
It is silicone for gluing aquarium, brand is *Soudal*, name *Silirub AQ*.
Here i the link to their website (I think it is a belgian company):
http://www.soudal.com/soudal.asp?o=Construction&p=ARTICLEDETAIL&srt=106&id=1068&lan=EN
You can download a datasheet from there. The technical datas are very close to the GE silicone used by Scolley.
Price was 4.30 Euros (5.40 US$) per cartridge including shipping (to France not to UAE...)

Something I did not mention in my previous post is that, following Wendle's advice, I was extremely carefull for not letting the silicone cartridge nozzle touch the glass while laying the silicone "worm" on it. I cut it wide, as adviced by Wendle, and most probably the more difficult is to hold the tip at constan height above glass while going forward and applying pressure to the gun to get a constant flow...
I was getting better at this while doing the last panel  

I used one cartridge for gluing the sides first. It was not empty then but I started to lay silicone on the front panel with a new cartridge to avoid laying the silicone worm with a "cut" in the middle.
I did the same for the back, so I used 2 and 1/2 cartriges.

Here is the picture of tank just after finishing the assembly process:









Hope this will help....
I will be happy to answer any question if you need some more details !

Once again thank you all for all the advices and tips !
Without that, and without Scolley incredible multiple threads describing with all possible details his heroic adventure, I would never have imagine I was able to try that and even better to achieve it at my first try !!!!

But with this incredible amount of shared information there was no doubt in my mind that I was going to do it !

*Merci Monsieur Scolley and Merci to everybody who contributed to the adventure !*

Sietch


----------



## scolley

_Il a été mon plaisir, et félicitations sur votre succès Monsieur Sietch._


I think it is great that between this success, and Wendle's contributions, we are assembling a nice little body of knowledge that other people can learn from - and act upon.

OK folks. I did it. Seitch did it. Wendle's done it. Your turn.


----------



## nawiatren

Thank you all for sharing your knowledge here. I am planning to build a tank with the dimensions 24" x 18" x 17" (height). Will 6mm glass be sufficient to build the tank without bracing. Please give me some advise. Thank you.


----------



## scolley

Check the table in the technical document my reference sources in the first post. The answer to that, and most, thickness question is found there. If you can't understand the document - but after you have tried - PM me and I'd be glad to help.

But look at the thickness tables at the end of the document first OK?


----------



## nawiatren

scolley said:


> Check the table in the technical document my reference sources in the first post. The answer to that, and most, thickness question is found there. If you can't understand the document - but after you have tried - PM me and I'd be glad to help.
> 
> But look at the thickness tables at the end of the document first OK?


Thank you so much.  very helpful.


----------



## wendle

nawiatren said:


> Thank you all for sharing your knowledge here. I am planning to build a tank with the dimensions 24" x 18" x 17" (height). Will 6mm glass be sufficient to build the tank without bracing. Please give me some advise. Thank you.


hi,
6mm is right on the borderline for your unbraced 24" x 17" face. I would build one for myself with 6mm, but not for a customer :icon_lol:
I used to be able to get 8mm, which was nice to work with and worked well for this kind of sized tank, unfortunately it is not as common anymore, and you might want to step up to 10mm.


----------



## Badcopnofishtank

Love the info Scolley and Wendle.
I will be replacing a pane from my 240 gallon tank this fall and this info is helpful. 

I wonder if I could do away with the plastic molding on the top and bottom edges if I make some braces along the top a la ADA style? 
I am considering the low iron glass for this to. How much more was it for you?


----------



## scolley

Wendle better take that one. I don't know a thing about braces. But braces won't help you on the bottom.

As for the cost of low iron glass, for a tank that size, in what has to be 1/2 to 3/4" thick - it's gonna be more than $100 for that piece. Maybe more than $200 - that is unless you can talk someone out of a remnant. That's a big piece of low iron glass.

And depending on how your tank is displayed, it could be a waste. If there is no ambient light, and the tank only has light shining in the top, it would be OK. But if there is a lot of ambient light coming in from around the room, those 3 other sides are going to color your tank anyway, in which case I wouldn't bother.


----------



## Badcopnofishtank

The room it will be in is a west room that gets only little light during the day, so no worries there. 

As for the braces, I will determine that when I pull all of them off of the tank and get the exisisting glass cleaned up. If it looks feasible, I may attempt it. 

It currently has a huge ( 2 foot long piece) of 1/2" thick glass in the top middle of the tank. Not really the best for a planted tank.


----------



## pineapple

This is a bonzer thread. The info is great. The initial write up is excellent, Scolley.

What type of maximum size would you recommend for a first-time "throw away" test tank. Would a 60 x 45 x 45 cm be too large to handle? It's a practical size - but I'd rather not get in over my head, so-to-speak.

Do the ADA tanks or Aquarium Obsessed tanks build the same way as Wendle - i.e. have the sides assembled around the base (rather than on top of it)?

Andrew


----------



## scolley

Andrew - I've NEVER seen an ADA tank in person. But I've been looking REAL hard at the many ADA publications that I have, and I'm convinced that they do it as Wendle describes. I guess I'm just lucky that I did not screw up worse.:icon_redf 

As for the test tank, I suppose it depends on what you are testing... anything in the 10-20g size gives you a taste of the issues involved (like how unbelievably messy and hard to remove silicone can be!) and still keep the glass thin enough for it to be cheap.

As you start to get to larger sizes, requiring 3/8" glass or thicker, you are going to get a feel for the issues associated with hefting heavy glass in the assembly process - but then you are spending a lot of money on glass for a "throw away" tank.

No, I'd definately recommend something in the 10-20g size range, unless of course money has no meaning for you. In which case, please send me a PM... :hihi:


----------



## pineapple

scolley said:


> As for the test tank, I suppose it depends on what you are testing...


I reckon I'd be testing me, more than anything else! ;-) Especially the planning and preparation phase. I was wondering whether the seams for 60 x 45 x 45 would be too long to handle for a beginner. Maybe I'll just give it a shot - depending on the cost of glass and availability in NYC.

I'm inspired by understanding how things work and how to make QUALITY ITEMS (rather than some DIY stuff which is cheap and cheerful but not very good looking as regards quality). The shipping fees are expensive and I'd as soon save some money too. I can put that to good use on my other hobby, cameras.

I think I'm going to give this a shot and replace my 20g All Glass tank in the office. I'll keep my eye on this thread and I hope, one day, to contribute something too.


----------



## Sietch31

My own philosophy is that you very often succeed at the first attempt, but the second time not (ask your wife when she tries a new recipe...)

So I would advice you to go directly for your definitive tank, the pressure will make you organize very well, checking everything twice and not feel too much confident...

Plus with all the experiences shared in this board you have a lot of info !

But may be it works that way only for me....


----------



## scolley

Sietch31 said:


> My own philosophy is that you very often succeed at the first attempt...


Yeah, that sounds good. But I gotta ask, have you gotten all (and I mean all) that excess silicone off your tank yet?

If so, then maybe your suggestion makes sense. And if not, maybe a test tank would have been a good idea.


----------



## Sietch31

:icon_mrgr :icon_mrgr :icon_mrgr 

Good point Steve !!!

No I havent...

I did it on the outside, with razor blades.
I used 5 packs of 5 blades (for cutting exess siliconne under tank, and cleaning external corners).
THe secret I discovered is that you cannot use a blade for very long, after may be 10cms (3") scratching becomes very much less efficient !

And it is OK now for the exterior of the tank. Took me couple of evenings though...:icon_roll 

What is remaining is a very thin layer of silicone inside the corners (around 1" wide) left by the credit card sides...

But I haven't drained the tank since I tested it first, I will clean that just before I start laying my soil...


----------



## wendle

Practice makes perfect, build a couple more tanks and you will have NO silicon to clean off other than dry squeeze out, which can be cut away in seconds.I don't know about the credit card idea, that is a fairly long edge to distribute a mess across the glass. If you are going to use that method spray the glass and the card with a little soapy water first.
For the man asking about the plastic bracing, any plastic won't be adding to the structure of the tank. A lot of mass produced tanks just have plastic trim so they can be handled a bit more roughly in transit without damage. I haven't paid any attention to how ADA brace their tanks, but the best way is a 30-40mm rib all the way along the front and rear panes, and then 100-150mm braces running front to back on top of them. Gives you a large glue area plus provides a recess for lids to sit down into. I think planted tanks are better off without lids. Better off without braces where possible, but that adds expense by needing heavier glass.


----------



## CardBoardBoxProcessor

I want to amkea tank.. something long wide.. but not too high.. haha odd huh?

something small though.. where could one get glass for a pratice tank but one that might wanna keep? :icon_eek:


----------



## scolley

Try any local glass shop - people that make window panes.

Look at the tables I provided in the links in my first post to find the thickness of glass you need. You said "not too high", so I'll wager you'll find 1/4" is thick enough. If so, your glass shop will have it in abundance, and will sell it to you cheap.


----------



## CardBoardBoxProcessor

I wish I had money and my own place.. I would have a Goldfish pond and a self made tropical tank.. -sigh- 

mm.. wel I am not gonan try to make my own 50 gallon.. I just was offered one free from my friend haha 55 even!


----------



## plantbrain

Scolley, 

The 75 gal 120 cm ADa tank is awesome and worth the hassle for around 480$

I modified a 75 gal AGA tank and made braces.
See the Dallas Forth worth site under plant fest 2004, you can see a little of it.

Cost: 300$ total.

The ADA tank looks better and if I paid myself 5 $ a hour, I'd probly lost money doing my own.

With larger glass tanks, weight and shipping really make it tougher.

Nice well made acrylic tanks are an option as well.

Every giant tank I owned was a broken tank I got for free and fixed.
I had a 100, 125, 135, 180 and 240 that way.

Smaller tanks are nice to make, I like making cube tanks.


Regards, 
Tom Barr


----------



## scolley

plantbrain said:


> Scolley,
> 
> The 75 gal 120 cm ADa tank is awesome and worth the hassle for around 480$
> 
> I modified a 75 gal AGA tank and made braces.
> See the Dallas Forth worth site under plant fest 2004, you can see a little of it.
> 
> Cost: 300$ total.
> 
> The ADA tank looks better and if I paid myself 5 $ a hour, I'd probly lost money doing my own.
> 
> With larger glass tanks, weight and shipping really make it tougher.
> 
> Nice well made acrylic tanks are an option as well.
> 
> Every giant tank I owned was a broken tank I got for free and fixed.
> I had a 100, 125, 135, 180 and 240 that way.
> 
> Smaller tanks are nice to make, I like making cube tanks.
> 
> 
> Regards,
> Tom Barr


Thanks Tom. As to your specific quote below...



plantbrain said:


> With larger glass tanks, weight and shipping really make it tougher.


...I contacted the Senske's, and the shipping of one of their 75's to Connecticut was INSANE. Of course, ADG had zero control over that. It was just one of the factors in the decision to build.

If I had to do it all over again, I might seriously consider buying that 75g ADA tank, and just sucking up that shipping charge. Building to my satisfaction was a real PITA. But like everything in this hobby for me, I had to learn that the hard way. If I had known how much material cost, tool cost, time, and frusteration would have been involved, the ADG+shipping cost would have seemed much more reasonable.

At the same time, though it WAS NOT an original criterion, it is indeed nice to say, "Yes, I built that." And BTW - I am only able to say that because, to a large extent, of the help from your good advice.

Thank you Tom.


----------



## plantbrain

I'm getting 2 of the 6ft long ADA 15mm glass tanks and a couple of the 75's.

I, of course, always build my own stands, I've never bought a stand actually.
Same with CO2 but will likely get the ADA pollen glass 30's and use a venturi mazzii.

There are areas to save $$ and some that many are just better off leaving.
But, if you don't have such access to the products, poor, etc, you have to make do.........

Been on that side of the fence too
But perhaps if you go in with some other local folks for a pallet shipment, you can get a better shipping deal.



Regards, 
Tom Barr


----------



## scolley

plantbrain said:


> But perhaps if you go in with some other local folks for a pallet shipment, you can get a better shipping deal.


Up in the Northeast, where we have no local access to such products, that is indeed the way to go. A bulk order can drop those per unit shipping costs dramatically. If I had had other people to go in with me on a buy, I would might have bought. Not sure though, as the would not have given me the non-tempered bottom that I was dying for (for bulkhead drilling).


----------



## Khandurian

Hi scolley,

I'm looking for some clarification on the GE RTV108 please. Is this the stuff your talking about?


----------



## scolley

When I was using it I wanted it in caulk gun sized tubes - so I've not seen those exact tubes. That looks like the stuff though. It says RTV 108 on the tube.

Also, when I was looking, I think I recall only seeing it in the colors BLACK and TRANSLUCENT. I got the latter, and found that it does not mean clear, but it is rather semi-clear. A little you can see through, but a thick bead will dry to look whitish. The BLACK I assume to be just that.


----------



## Khandurian

Hey folks, Just wanted to let ya'll know that I attempted something close to what Scolley here has done. 

He started with all new glass. I started with a 55gal found on the side of the side of the road with both sides blown out. Now, my seams are not as pretty as his. But I did a good job of sealing this baby all back up!

You can read about it over at Fish Geeks! 

My first attempt was a real downer, the tank leaked, albeit a very slow drip, but it still leaked. After reading over this thread, I got alot of good information and helpful tips. 

I used GE RTV108. Simply due to the fact that I had 20 tubes for free! I am happy with the results being this is my first attempt to take on a challenge of this magnitude. Enjoy!


----------



## scolley

Hey! Congratulations Khandurian! And thanks for posting that link here. Maybe people see yet another example that it can be done!

It's a pretty good feeling when you get it right, don't you think! Job well done.

I'm amused by your difficulty with the bubbles in the seams. I had the same trouble. But I think I figured that out... think it has to do with the speed at which you squeeze out the silicone (fast is good), pushing out a wide bead (as opposed to swaying back and forth to make it artificially thick - needs do come out thick) and slowly tipping the glass up onto a side (not pressing is straight on). But I'm not sure. Just like yourself, as I went along my seams got much better. 

Thanks for sharing. Tank looks great!


----------



## KoiGuy

Very impressive.

But for the average person, buying the AGA 75gal is cheaper & safer. 

I like the plastic molding base & top. 

$200 for just the glass & $170ish for an AGA tank @ the store.

Where would you get the plastic moldings anyway?


----------



## aya7med

thanks alot scolley 

you made perfect and creative work 

i hope to make like this but i need to gain alot of experince in this hobby 

thankkkkks


----------



## mcox

*Silicone & interior bottom bracing*

A couple of questions...

Is GE RTV 108 and GE SCS 1200 safe to use? By that I mean, will the compounds used to make it leach in time out into the water and poison the inhabitants?

Anyone know what the Adhesion and/or tensile strength is for RTV 108? I can find that the 1200 series has a tensile strength of approx 485 psi, but can't find anything on the RTV 108. 

I read somewhere that most of the strength in a glass to glass bond is in between the panels where glass touches glass and that the interior seam is mostly there for looks and some protection from compromising the glass to glass seals and likely some additional leak protection. That being said, it seems to me that having an additional bottom interior perimeter bracing using 2-4" glass might actually help prevent seal failure. 

What are your thoughts regarding? Thanks mc


----------



## greenleaf888

scolley I seriously considered building an all glass aquarium, but ultimately decided against the idea. I found price wise it really wasn't much cheaper and depending on size, it can be a gamble to say the least. 

I must say I find it interesting how so many people want a flawlessly seamless aquarium and the risk they are willing to take to achieve this. I for one wouldn't dream about making an aquarium without bracing, deflection equals bad news in my books. As for the silicone, I don't believe making such a fine bead is a good idea. Cosmetically I think very few people would pay attention, let alone appreciate such a fine detail, so why risk catastrophic failure? I personally believe one contribution to your initial failure was a result of trying to have such a fine silicone bead. DIY is all personnel preference however, and I must thank you for the in depth article and your attention to detail. Your finished product looks amazing, one of the best I have seen. And you defiantly did your research, I know I picked up a few intriguing tips. 

If I were going to build an AGA I would build spacer blocks. You could make them slightly larger than your end pieces to achieve a perfect silicone seem with a nice consistent thickness top to bottom. I would also probably not use clamps, as you stated earlier you risk pushing all the silicone out of the seem with to much pressure. Also many articles I have read suggest that using tape is the best method, you only really need to hold it all together with light pressure while the silicone sets.

Anyways I thought I would revive this thread with my two cents, as it was a really interesting read. My big DIY project will be a 220 gallon glass plywood tank. I know many planted tank enthusiasts don't really appreciate glass plywood tanks and would much rather have a flawless glass box which is very attractive, but for me it's an issue of what is more reliable and practical. Besides that I am a carpenter, so a glass plywood aquarium is right up my alley.


----------



## scolley

mcox said:


> Is GE RTV 108 and GE SCS 1200 safe to use? By that I mean, will the compounds used to make it leach in time out into the water and poison the inhabitants?
> 
> Anyone know what the Adhesion and/or tensile strength is for RTV 108? I can find that the 1200 series has a tensile strength of approx 485 psi, but can't find anything on the RTV 108.
> 
> I read somewhere that most of the strength in a glass to glass bond is in between the panels where glass touches glass and that the interior seam is mostly there for looks and some protection from compromising the glass to glass seals and likely some additional leak protection. That being said, it seems to me that having an additional bottom interior perimeter bracing using 2-4" glass might actually help prevent seal failure.


As far as the RTV108 being safe, all I can say is that once I finally got through to an honest to gosh silicone guru at GE, he said it was what aquarium manufacturers use. So IF I'm repeating that accurately, and IF he really knew what he was talking about, then I think it is a good assumption that it is safe for fish.

As far as the tensile strength is concerned... tensile strength is almost irrelevant. The cheap, over-the-counter "aquarium" silicone apparently have sufficient tensile strength. The issue is adhesion strength. Not tensile. And that is apparently where RTV108 shines.

As far as the bottom interior brace, apparently an additional layer of bottom glass is often used - maybe for the reasons you suggest. I honestly do not know.



greenleaf888 said:


> scolley I seriously considered building an all glass aquarium, but ultimately decided against the idea. I found price wise it really wasn't much cheaper and depending on size, it can be a gamble to say the least.
> 
> I must say I find it interesting how so many people want a flawlessly seamless aquarium and the risk they are willing to take to achieve this. I for one wouldn't dream about making an aquarium without bracing, deflection equals bad news in my books. As for the silicone, I don't believe making such a fine bead is a good idea. Cosmetically I think very few people would pay attention, let alone appreciate such a fine detail, so why risk catastrophic failure? I personally believe one contribution to your initial failure was a result of trying to have such a fine silicone bead. DIY is all personnel preference however, and I must thank you for the in depth article and your attention to detail. Your finished product looks amazing, one of the best I have seen. And you defiantly did your research, I know I picked up a few intriguing tips.
> 
> If I were going to build an AGA I would build spacer blocks. You could make them slightly larger than your end pieces to achieve a perfect silicone seem with a nice consistent thickness top to bottom. I would also probably not use clamps, as you stated earlier you risk pushing all the silicone out of the seem with to much pressure. Also many articles I have read suggest that using tape is the best method, you only really need to hold it all together with light pressure while the silicone sets.
> 
> Anyways I thought I would revive this thread with my two cents, as it was a really interesting read. My big DIY project will be a 220 gallon glass plywood tank. I know many planted tank enthusiasts don't really appreciate glass plywood tanks and would much rather have a flawless glass box which is very attractive, but for me it's an issue of what is more reliable and practical. Besides that I am a carpenter, so a glass plywood aquarium is right up my alley.


Building yourself is definitely not always going to be cheaper. Shipping cost will make a big difference - if that applies to you as it did me. I had a special requirement - all glass, small seams, low iron glass, with holes drilled in the bottom. It was the last part that was the kicker. I would strongly suggest anyone buy a commercially built tank instead - if you can get one that fits your requirements.

Spacer blocks seem like a good idea. I've not seen it done though. As for tape vs. clamps, well that depends on how far you crank the clamp. And silicone is like grease on glass, and once that glass get's 1/2 inch thick, it gets heavy. It WANTS to slide around - big time. I believe all the tanks I've seen done with tape have been much smaller and/or thinner glass. I made a smaller tank with tape. It's easy with as small tank.

But if do it with tape, please post your results. Good luck.


----------



## lemonlime

I just wanted to thank you for documenting this project, a true legend thread on plantedtank. Inspirational.. I would like to do something similar one day.


----------



## mcox

*Thanks*

I also want to thank you for documenting, let's keep this going and get as much opinion, tips, success/failures on here as possible.


----------



## lostparadise

All I can say is that fascinating article! and so thanks for posting it. I am very impressed with your tank..


----------



## wendle

scolley said:


> I'm amused by your difficulty with the bubbles in the seams. I had the same trouble. But I think I figured that out... think it has to do with the speed at which you squeeze out the silicone (fast is good), pushing out a wide bead (as opposed to swaying back and forth to make it artificially thick - needs do come out thick)


Some tubes just have bubbles in them, not much you can do about it. Sometimes they are just tiny little pin pricks. Sometimes they are like the size of an m&m and go "pop" and make the bead fall off the end of the nozzle. You can syringe a bit of silicon into these holes while assembling if they are really unsightly.

You _have_ to push out a wide bead in one go, running multiple passes is a recipe for disaster. Cut the nozzle to suit the thickness of your glass.

If you can't find the GE RTV in your area try for Dow Corning V2. It is just as good. I prefer the Dow product for black, it is "blacker".

:thumbsup:


----------



## scolley

*Reflections over time...*

My tank building adventure was one I would be a poorer man had I not gone through. And it is wonderfully gratifying to know that my documentation of this journey has helped other people! That was always my hope.

But with a few years separation from the build, and subsequent bust, of my tank, I have a few things that I am ABSOLUTELY convinced of. And that may be of benefit to you, if you are considering building a tank.

*Chosing the right silicone is paramount. *In this post, you see the thin seam that I used that was not RTV108. That seam - the one in the post - is the exact seam that burst the day after I spent time scraping the tank walls of GDA. That seam did not hold up to pressure. But the seams on the front of the tank did - those held with RTV108 vs. normal "aquarium" silicone.

*Proper arrangement of the glass panes is critical.*
In this thread wendle makes it clear that the sides of the tank should be attached to the bottom, as opposed to resting on the bottom pane as I did. While I had my reasons at that time, I'm convinced that they were wrong. Here is a wonderful post that illustrates why. So don't copy my design... have your side abut the bottom, not resting on it. Here is a post that describes why... That will maximize the holding properties of the silicone you use. And if you don't believe me, just look at my tank and see the multiple times mine had to be resealed at the bottom, and ultimately required immense seams to hold. Why? Because I made the mistake of putting my sides ON TOP of the bottom pane instead of ABUTTING AGAINST it as I SHOULD HAVE.


Hope this helps. Good luck with your tank building experiences. This was my first big one. But with what I've learned.... it WILL NOT be my last. :icon_wink


----------



## fish590a

Wendle,

Maybe I missed it, but do I apply the silicone on the front, back and bottom of sides?


----------



## wendle

fish590a said:


> Wendle,
> 
> Maybe I missed it, but do I apply the silicone on the front, back and bottom of sides?


Not sure if I am reading your question correctly, but if it is the question I think it is this is the best way to describe it;
You want a bead along the bottom of the inside face of the sides (calling them ends is maybe a little less confusing?)
You then want a bead along the bottom and both sides of the inside face of the front and back.
All beads should be applied to a "face" not an "edge".

I hope that makes sense, I am not much of a wordsmith.

Seeing as this thread seems to have remained a popular read, if I get time I would like to assemble a small tank and accompany it with a plethora of step-by-step photos.
I have a couple of tanks to build for people once I finish the car I am building, one of these tanks is a plain and simple 4' x 2' x 2'. That is probably a good candidate to photograph.


----------



## scolley

wendle said:


> Seeing as this thread seems to have remained a popular read, if I get time I would like to assemble a small tank and accompany it with a plethora of step-by-step photos.


That would be killer Wendle! If you get the chance, please do!


----------



## Wasserpest

scolley said:


> *Assembly time*
> If you allow a silicone bead that goes between two pieces of glass to “skin over”, or form a slight film on its surface before you press the glass together, you should prepare for that seam to fail under pressure. Generally that means that you MUST press the glass in place within a few minutes of laying down the silicone bead. IMO 2 minutes is safe for the professional grade silicons I reccomended earlier, 5 minutes for commercial grades. Any longer and you are accepting an element of risk.


This sounds scary... so you have to really hurry (<2 minutes for RTV108) to get the silicone applied and the glass panes attached to each other.


----------



## scolley

That's why you need to practice on a little (cheap) tank first. And then practice EVERY SINGLE motion you are planning to make before you do it. And then, since you are only doing one pane at a time, that limit is not so bad.


----------



## Wasserpest

I hope 2 minutes is a bit on the extreme side. Working on a plywood tank, where the front glass needs to be glued on all 4 sides at the same time, I wonder if it is even possible to squeeze the cartridge fast enough to get it all out, and then lower the glass (slowly??) onto the glue.

Maybe for that purpose it would be better to use the non-professional type with less strength, but a bit more flexibility with the extended dry period.


----------



## Gatekeeper

Wasserpest, speak with Jens. He did a bang up job on his 90 gallon (formerly Jay Luto's tank that ruptured). He may have some pointers for you!


----------



## malaybiswas

Hey Scolly

I have started my project on a 22 gallon ADA style rimless tank. While mine is not as ambitious as your 75 gallon project, I did read all 44 pages of that post. It was definitely informational and your perseverance is commendable. 

I have a question on RTV108. I have been trying to find out that product and have searched at local HD, Lowes, Ace but not seen it. When I mention "RTV108", I get looks as if I just landed from Mars . Can you share a photo of it if you have so that I know what to look for next time?

Malay


----------



## PDX-PLT

malaybiswas said:


> I have a question on RTV108. I have been trying to find out that product and have searched at local HD, Lowes, Ace but not seen it. When I mention "RTV108", I get looks as if I just landed from Mars .


Google is your friend: http://www.altex.com/RTV-Silicone-Clear-28-oz-RTV-108-P143191.aspx


----------



## malaybiswas

PDX-PLT said:


> Google is your friend: http://www.altex.com/RTV-Silicone-Clear-28-oz-RTV-108-P143191.aspx


Thanks a lot PDX-PLT. They have this!!!


----------



## _Green_

Hi Scolley,

Thank you for posting this, I'm planning to build my own tank in the next month or so. I've worked with glass for some time now and really didn't think it would be very hard at all, actually I still don't, but your article did touch on a few things I hadn't thought of so thanks very much 

The end result of your project looks out sanding. As I said above I'm planning my own tank and was told by more than a few people, (one of whom is the owner of the company I work for now) that I should not polish the panels because the seal will not be as good as it will in the glass is clean cut. So I'm wondering if you've had anymore problems with leaks since you last posted and how long has the tank had water in it?



scolley said:


> Well, I've gotten it from the experts that silicon sticks to silicon very, very well.


 I've spent the last year installing 3-5 custom shower units 5 days a week and can tell you fresh silicone does not bond well to old silicone. Reapplying is a royal pain in the neck.



scolley said:


> I also got it from the experts that no silicon manufacturer makes silicon that they will say works for aquariums. Other companies buy the manufacturers' silicone, who then repackage it, and call it "aquarium" silicon.


That may be partially true, however CRLaurence Co. does manufacture a product specifically designed for aquarium uses see it here they do not sell to the public so that will make it more difficult to obtain. I also just noticed they state at the bottom of the product page that it's not to be used for frame less tanks over 30 gallons.



scolley said:


> As to the fresh stuff sticking... well I sprung a LOT of leaks before everything was OK, but I never sprung one at at point where I joined cured (or semi-cured) silicon to fresh. So I trust the advice of the experts on that - silicon sticks to silicon. Or at least it does if it is not old silicon.


Maybe your information is correct, I don't recall ever getting a call back to fix a leak where we had to remove and reinstall a panel. What I do recall is that the panels were a pain to get back into place because the old cone caused them to slide real easy on the shims.


----------



## scolley

_Green_ said:


> I'm planning my own tank and was told by more than a few people, (one of whom is the owner of the company I work for now) that I should not polish the panels because the seal will not be as good as it will in the glass is clean cut.


That certainly sounds good. But keep in mind that the glass that the edge will abut to will be polished, so having one half of the bond getting a better grip may not help. Your likely point of failure is still silicone trying to remain adhered to polished glass. Maybe you minimize that risk because you've cut the number of such bonding surfaces in half. And do keep in mind, this is not about sealing - not in the sense that it's keeping the water in, and counteracting the pressure water is putting on the seal. That's not the dangerous stress. The danger is the pressure the water is putting on the wall of glass, creating shear forces that try to tear the edges apart. Resisting that requires strong adhesion strength, and silicone - as unlikely as this seems - is really poor at that.

Does that make sense? It's not the water pressure on the seal that's the problem. It's the water pressure on the huge pane of glass that creates the forces that tear the edges apart. 



_Green_ said:


> So I'm wondering if you've had anymore problems with leaks since you last posted and how long has the tank had water in it?


That tank had a massive failure one afternoon! Nearly 75 gallons on the floor within a minute or so. I've posted about that a lot here at PT. If you look, you'll find it.

By the time I learned about resonable construction techniques, and RTV108, I had developed a bit of bursitis in my arm from cleaning silicone. So while I knew that I SHOULD take apart the entire tank and use RTV108, I didn't. I only used it to repair leaking sides. As such, one long side was still attached with the old, crappy "aquarium" silicone. And about 12 hours after some hard pressure algae scrubbing on that side, it let go. 



_Green_ said:


> I've spent the last year installing 3-5 custom shower units 5 days a week and can tell you fresh silicone does not bond well to old silicone.


I believe I was referring to new, or freshly cured, silicone. If that was not clear, my apologies. My source was not referring to aged, dirty silicone.



_Green_ said:


> however CRLaurence Co. does manufacture a product specifically designed for aquarium uses see it here they do not sell to the public so that will make it more difficult to obtain. I also just noticed they state at the bottom of the product page that it's not to be used for frame less tanks over 30 gallons.


Do they manufacture it? Or just market it? The intent of my statement is that no one "makes" aquarium silicone. Plenty of vendors buy "aquarium" possible silicone and market as such. And the one you found is only good for up to 30 gallons, which basically tells you that it is crap. I personally would not touch it. Get something that will hold.




_Green_ said:


> Maybe your information is correct, I don't recall ever getting a call back to fix a leak where we had to remove and reinstall a panel.


Comparing the pressures on a shower door to an aquarium is comparing apples to oranges. Other than the fact that there is water in both situations, the applications, and the type of stresses that they put on silicone are very different.


Good luck with your project! :thumbsup:


----------



## sumoarigato

*pane orientation*

Steve,

I can follow along why it's suggested that the four panes should sit outside the bottom pane rather than on top of it.

But... 

Why are acrylic tanks made with the side panes sitting on top of the base pane? My initial thought would be to do exactly what you did. It just "seems logical" to put the four panes above the base to fully support the pressure. 

Even given the difference of glass-meeting-silicon-meeting-glass vs. acrylic-chemically-bonding-to-acrylic, it still seems that water pressure would act the same way, requiring the same solution.


----------



## Gatekeeper

Got me confused too. Although I believe the logic of the glass on the outside of the bottom base is because the silicone is stronger in tension then it is with a shear stress.


----------



## Hoppy

Just to complicate the discussion, GlassCages rimless tanks have extra strips of glass, same thickness, I think, "glued" to the inside of the bottom piece, on all four sides, so there is a double thickness of glass around the edges of that bottom piece. If Tom Barr is reading this thread he can confirm or correct this, because it is his tanks that I noticed this on. The effect of this would be to double the strength of the bond between the sides/front/back and the bottom piece.


----------



## scolley

sumoarigato said:


> Why are acrylic tanks made with the side panes sitting on top of the base pane? My initial thought would be to do exactly what you did. It just "seems logical" to put the four panes above the base to fully support the pressure.


Glen had it right about the shear strength of silicone being poor, requiring sides against the bottom, rather than on it. I screwed up, and that seems clear in retrospect. But I know why I decided to do it the way I did, and I'd wager dollars to doughnuts that it's the same reason acrylic builders do it...

When you set the glass around the outside of the bottom, the measurements of the side panes becomes much more critical than if you set them on the bottom. Think about it. When you are placing side on top of the bottom, you pin four sides together, and as long as they come close to meeting the edges of the bottom pane, you're OK. But when you wrap them around the bottom, if they aren't perfectly cut, you could have some nasty gaps, or the interior of the sides could be larger than the bottom. Bad problem.

Placing sides around the bottom is far less forgiving of small mistakes in cutting. But with acrylic, you just make sure the bottom is bigger than the connected sides... bond them on to the bottom, and trim any bottom edge excess with an acrylic cutting router bit. Much easier. And the whole shear vs. adhesion thing doesn't matter at all with acrylic, because once bonded, acrylic seams are actually stronger than the acrylic sheets.

BTW - did I mention that I'm doing work in acrylic now? Never without a project. :icon_wink


----------



## sumoarigato

*panes pains & silicone reference*

Steve (and Hoppy and Glenn),

Thanks... it all makes sense when you combine the nature of the bonds along with the feasability of cutting/trimming materials. With glass, you need those cuts to be consistent and even from the get-go, but with acrylic, post-trimming isn't a problem (and pretty much required anyways).

I also saw many comments about tracking down aquarium-safe silicone, and (before I read this thread) I simply wasn't able to locate any GE I in black (unless I wanted a case), nor any of the other tested alternatives easily. After a week of searching, I found a site that carries the All-Glass Aquarium Sealant (so we know it's as safe as we're gonna get), and it's only $6.50/10.3oz tube (!):

Clear:
http://www.herpsupplies.com/product.cfm?groupid=7193&id=AAG65003

Black:
http://www.herpsupplies.com/product.cfm?groupid=7192&id=AAG65004


Thanks again for this great post! I suspect you've saved many carpets/wood-floors with this thread!


I look forward to your acrylic experiment(s) as well!


----------



## rountreesj

Nowplan on doing a full rimless 36"x18"x18" tank with 1/2" glass. I need to get the final quote from a glass shop and an aquarium builder and see which is cheaper me doing it or someone else doing it. I feel confident that I can do it...But I just need to find where Steve says what kind of glass to use and why. Don't tell me, just point me where if you can, he told me to check the thread, but I think I missed it.


----------



## bpkenn

Wendle & Scolley,

Was hoping you guys could comment on my situation. I recently acquired a 45g hex tank with a leaking seam, and I am hoping to reseal it. 

It looks as if there are gaps between all the pieces of glass, and there is plastic molding on the top and bottom. I assume that i could use the plastic molding to hold the glass pieces in places while i silicone them, but how can i do this effectively within 2 minutes?

Thanks in advance


----------



## Firestarter

I was thinking about doing something like this with an industrial glass adhesive and then using a bead of silicone on the inside just in case the glass adhesive is not aquarium safe. Any info would be appreciated.


----------



## scolley

sumoarigato said:


> I also saw many comments about tracking down aquarium-safe silicone, and (before I read this thread) I simply wasn't able to locate any GE I in black (unless I wanted a case), nor any of the other tested alternatives easily. After a week of searching, I found a site that carries the All-Glass Aquarium Sealant (so we know it's as safe as we're gonna get), and it's only $6.50/10.3oz tube (!):


You have been reading this thread, right? That stuff is CRAP. If you want to use it on a really shallow tank (I'm guessing 12") then it's fine. But I'd strongly advise you against using it for building a tank. I've done it - successfully, in small tanks. But once you get to any depth at all, it's worthless.




rountreesj said:


> Nowplan on doing a full rimless 36"x18"x18" tank with 1/2" glass. I need to get the final quote from a glass shop and an aquarium builder and see which is cheaper me doing it or someone else doing it. I feel confident that I can do it...But I just need to find where Steve says what kind of glass to use and why. Don't tell me, just point me where if you can, he told me to check the thread, but I think I missed it.


I'm not sure glass was covered here at all. But the links I provided for selecting glass thickness, up front in the first, long post were for normal "float" glass that any glass shop can provide you. If you want another type of glass like starphire or some other low-lead glass, just inquire about its strength over standard "float" glass.




bpkenn said:


> Wendle & Scolley,
> 
> Was hoping you guys could comment on my situation. I recently acquired a 45g hex tank with a leaking seam, and I am hoping to reseal it.
> 
> It looks as if there are gaps between all the pieces of glass, and there is plastic molding on the top and bottom. I assume that i could use the plastic molding to hold the glass pieces in places while i silicone them, but how can i do this effectively within 2 minutes?
> 
> Thanks in advance


Sorry. This is not a "I'm fixing my broken tank" thread. It's about building from scratch. Maybe start a new thread???




Firestarter said:


> I was thinking about doing something like this with an industrial glass adhesive and then using a bead of silicone on the inside just in case the glass adhesive is not aquarium safe. Any info would be appreciated.


What you are suggesting appears to be done by a number of aquarium manufacturers, possibly including ADA. But I've found no good information about this. So if you find some GOOD, RELIABLE info, please share it. Thanks.


----------



## Firestarter

Not sure if this would work with such a large scale as a 75g aquarium but would be well worth the peace of mind knowing that the bond is permanent and maybe no silicone required.

http://www.dymax.com/products/glass/index.php?gclid=CNWT5oHWp58CFWpd5QodkgQd1A


----------



## srud

Firestarter said:


> Not sure if this would work with such a large scale as a 75g aquarium but would be well worth the peace of mind knowing that the bond is permanent and maybe no silicone required.
> 
> http://www.dymax.com/products/glass/index.php?gclid=CNWT5oHWp58CFWpd5QodkgQd1A


I would recommend contacting Dymax before selecting an adhesive. I had tried to find an adhesive that would bond glass to sheet PVC and they (Dymax) had an issue with the constant contact with water. Perhaps the adhesive for glass to glass is better.


----------



## Hoppy

If there was a better method for assembling a glass aquarium than with silicone, wouldn't you be seeing some of the many companies that make aquarium tanks using it? Silicone isn't so easy to use, and so inexpensive that manufacturers use it for those reasons. So, it must be that it is the best adhesive they have found for this use. I certainly wouldn't want to risk having 75 gallons of water suddenly splash onto my wood floor, just based on a hope that a different adhesive would work well enough.


----------



## srud

Hoppy said:


> If there was a better method for assembling a glass aquarium than with silicone, wouldn't you be seeing some of the many companies that make aquarium tanks using it? Silicone isn't so easy to use, and so inexpensive that manufacturers use it for those reasons. So, it must be that it is the best adhesive they have found for this use. I certainly wouldn't want to risk having 75 gallons of water suddenly splash onto my wood floor, just based on a hope that a different adhesive would work well enough.


Hoppy, I agree completely. What I was trying to say was that maybe the Dymax adhesive for bonding glass to glass was better (more water resistant) than what they had for bonding glass to PVC. Not better than silicone. 

It seems that many UV adhesives break down when in contact with water. Not a good thing if you want the joint to hold back 75 gallons (or more) of water. I suppose you could always seal the joint with silicone, but I'd always have that nagging doubt about what if...


----------



## scolley

srud said:


> I suppose you could always seal the joint with silicone, but I'd always have that nagging doubt about what if...


No reason for nagging doubt... the simple fact is that a good number of manufacturers of tanks adhere glass-to-glass with adhesives other than silicone. ADA included. 

I've heard the process referred to as "welding", but honestly I don't know how they do it.

Fact is... it's a closely guarded trade secret. But I'd HIGHLY encourage anyone that has insight into the actual, successful, use of alternate bonding methods for aquariums to post that info here!

Thanks.


----------



## Tamelesstgr

Question,

Can I use Denatured Alcohol or does it NEED to be Acetone to clean the seams before gluing? I will be using the GE Silicone I.

I plan on using some 1/4" glass that I have had lying around for ages. All sides are polished with a beveled edge, I should end up with almost a 12x12x14 when it's put together.

Thanks,
Ken


----------



## Sietch31

Hi there !

It's been a long time since I last came...
Hope you're all well




scolley said:


> No reason for nagging doubt... the simple fact is that a good number of manufacturers of tanks adhere glass-to-glass with adhesives other than silicone. ADA included.
> 
> I've heard the process referred to as "welding", but honestly I don't know how they do it.
> 
> Fact is... it's a closely guarded trade secret. But I'd HIGHLY encourage anyone that has insight into the actual, successful, use of alternate bonding methods for aquariums to post that info here!
> 
> Thanks.


These are glues cured with UVs 
Never heard of a DIY use though..

By the way, my DIY frameless/braceless tank is still holding water well :red_mouth

It was worth the test


----------



## luckyfind

I know this is an old post but has been going for a long time.
It is very informative but I have a few questions.

I got a 5ft 108 gal tank that was brand new but with a broken end.
I want to replace the end with new glass.I have taken out the glass and cleaned up the old silicone on the botom and sides.

1 Can I have a piece of glass cut say 1/8 in. shorter than the original piece,put silicone around the 3 sides and slip it back into position without having to take the top trim off? Then silicone the insides?

Any ideas or suggestions would be appreciated.
Laurence


----------



## jlroar

For the Technical Guru's out their Here is some information on the Silicone.

http://www.momentive.com/momentiveInternetDoc/MPM/Static Files/Documents/Data Sheets/2047.html

If my uneducated self understands this the black Silicone RTV-103 is the same as RTV-108. It also is not really designed for the typical user but something special that more than likely will need to be ordered via the net.

BTW the lowest price I have found for it was at the following link.

http://www.grainger.com/Grainger/items/1FBH8

I was researching this because I am going to re-seal my new (to me) 72 gallon bow front leaky tank.

James


----------



## doctorp

I know this is an old thread but I just love this tank!

I am about to embark on the construction of a similar tank and wonder now that you have had this tank running for some time, would you mind giving me some advice on the bulkheads?

I am looking to install 4 bulkheads, evenly spaced along the back third of the tank. I plan on keeping two spare for flexibility. Given you have had time to appreciate what you would do differently, where do you think I should place the bulkheads?

I plan on running my heating, filter, and CO2 reactor all in-line underneath the tank. Due to the amount of equipment I may run two external filters instead of one, and spread the load of the extra equipment.

Any help would be greatly appreciated.


----------



## willknowitall

scolley said:


> Glen had it right about the shear strength of silicone being poor, requiring sides against the bottom, rather than on it. I screwed up, and that seems clear in retrospect. But I know why I decided to do it the way I did, and I'd wager dollars to doughnuts that it's the same reason acrylic builders do it...
> 
> When you set the glass around the outside of the bottom, the measurements of the side panes becomes much more critical than if you set them on the bottom. Think about it. When you are placing side on top of the bottom, you pin four sides together, and as long as they come close to meeting the edges of the bottom pane, you're OK. But when you wrap them around the bottom, if they aren't perfectly cut, you could have some nasty gaps, or the interior of the sides could be larger than the bottom. Bad problem.
> 
> Placing sides around the bottom is far less forgiving of small mistakes in cutting. But with acrylic, you just make sure the bottom is bigger than the connected sides... bond them on to the bottom, and trim any bottom edge excess with an acrylic cutting router bit. Much easier. And the whole shear vs. adhesion thing doesn't matter at all with acrylic, because once bonded, acrylic seams are actually stronger than the acrylic sheets.
> 
> BTW - did I mention that I'm doing work in acrylic now? Never without a project. :icon_wink


im thinking of making a large tank my self and this is a sticking point for me
on one hand it would be easier to place front and side panes on the bottom
but perhaps placeing them around bottom is not only that it would have less shear strenght problems 
but also would stop the the weight of the glass panels from pushing out to much silicon from the seams


----------



## scolley

Folks... I'm THRILLED that this thread is still alive. Goodness knows I poured a copious amount of my own ignorance and experience into it, in the hopes that it would be starting point for other people to learn from. And to my delight, that appears to have happened. But it has not all been restricted to Planted Tank.

There's a gent at Reef Central - Uncleof6 - that has this stuff down cold. Here's an example post of his appreciable knowledge.I STRONGLY reccomend that you go to Reef Central, and do a search on his name, or on SCOLLEY (my name), or RTV108, to find a wealth of knowledge on how to do this. It's not rocket science.

My problem was... that I was a pioneer in the states. And you know how to recognize the pioneers. Right?

They are the ones with the arrows in their backs! 


PS - I'm still CONVINCED that my final product was ok, EXCEPT for the fact that I did not remove the crap silicone (that ultimately failed) on one side and replace it with RTV108. I KNEW at the time I should do that, but my repeated mis-steps in getting to the point of having a leak free tank caused enough bursitis in my arms to cause me to decide to give the mixed silicone tank a go. My mistake. It's been a BITCH to post the arduous detail I have posted to help YOU learn. So please don't repeat my mistake.

That will make all my effort worth it - If YOU succeed.

Thank you.


----------



## lugia

It must be almost IMPOSSIBLE to build a tank like that! WHOA!


----------



## hazena

*Nice Tank*

COngrats on your creation! Beautiful! I found myself making a 60 gal aquarium in much that sam way and I was left all by myself in the process. But is was a terrific success and I plan on creating another. Why did you say to not use Tempered glass? I uses 1/4 tempered and one panel was 3/8 non tempered so I could bore the holes. Hopefully I can send some photos of how the tank went and is.

Good luck!

Hazen


----------



## Hoppy

Beautiful tank, but is that old trunk really strong enough to hold that tank? It looks precarious!


----------



## happi

is it just me, looks like tank is floating in the air.


----------



## 10gallonplanted

That tank looks like it might have some trouble later down the road, since its hanging off the edge.


----------



## audioaficionado

Great sticky roud:

I've been wanting to make my own ADA style tanks in my preferred custom dimensions. I also want to make all the sides out of low Fe glass. It doesn't matter what color the bottom piece is. I'd do some Eurobracing to minimize any top side bowing or top corner unzipping stress. I figure the maximum practical height is going be 24" mostly because that's all the longer my arms can reach without climbing in. 150x75x60cm/60x30x24" would be my dream tank. Putting in those bottom bulkheads is genius because what's the point of hanging a bunch of hoses over a large rimless show tank. Also makes putting a jump proof clear screen frame over the top simple.

Bookmarked and thanx again for this thread.


----------



## shrimpNewbie

this is inspiring, although i want to make my own i was only thinking 15 gallon tall cube, 75g is epic, very impressive work.


----------



## Gold Finger

willknowitall said:


> im thinking of making a large tank my self and this is a sticking point for me
> on one hand it would be easier to place front and side panes on the bottom
> but perhaps placeing them around bottom is not only that it would have less shear strenght problems
> but also would stop the the weight of the glass panels from pushing out to much silicon from the seams


Absolutely right. I bought a cheap very old old hagan 75G took it apart and re glued it with scs. It didn't occur to me that the bottom plate might be inside until i pulled the bottom rim off and saw it. Upon considering it I came to the same conclusion as to why they did it this way. They cut the bottom sheet quite small (to be sure it would fit, i'm sure) This gives it a thicker seam here (about an eighth) which is fine since it doesn't hurt side shear and the downward water pressure is countered by the stand anyway.


----------



## Gold Finger

Two more warnings: 

1) silicone is good for only 12 months from the day it is packaged. Read the date.

2) Acetone (if not properly removed) is extremely detrimental to silicone's ability to adhere to glass. I don't use it.


----------



## Gold Finger

*To Build, and to Rebuild*

To me building a tank is a hobby unto its self. Something you do for the fun of it, not to save a buck. You probably wont save any money building a tank unless you get the glass cheap. Rebuilding a tank, however, is a great way to save money... and learn how to build a tank. I found an old 70G for cheap and rebuilt it with $24 worth of silicone. It is better now than the day it was first sold. The tear down and seal removal is pretty time consuming so I wouldn't do it again, but it was a great way to learn how to build a tank without having to pay full retail for the glass. Someday I'll use what I learned to build myself a custom, 16mm 100G starphire tank.


----------



## Gold Finger

hazena said:


> COngrats on your creation! Beautiful! I found myself making a 60 gal aquarium in much that sam way and I was left all by myself in the process. But is was a terrific success and I plan on creating another. Why did you say to not use Tempered glass? I uses 1/4 tempered and one panel was 3/8 non tempered so I could bore the holes. Hopefully I can send some photos of how the tank went and is.
> 
> Good luck!
> 
> Hazen


Tempered is stronger in some ways but explodes violently when it breaks. Normal plate glass just cracks. I don't know which I prefer. I'd use tempered for the bottom panel, but I'd look into how it handles bending (called deflection in tanks) before using it for side panels. I would use Starphire glass over either any day. I try to tell myself that I don't care about my tanks green tint, but I do. Starphire tanks are gorgeous!

P.S. your stand freaks me out!


----------



## hazena

*Stand*

Hey everyone, sorry I haven't posted or answered any questions. But I sure did receive alot of concerns about my trunk stand. Yes it is a trunk and heavens no, the trunk is not holding up hundreds of pounds of water! I am a metal artist and the trunk has three 1.5" X1/4" thick steel tubing holding up the weight of the tank. The tank looks like it is floating because the tubes are welded to a 1/4" plate of steel that the tank is suspended on. If I have time and if there is an interest I can send pics of how I did it.

Good luck and the tank is doing strong. 

Guud luck,

Hazen


----------



## Gold Finger

glad to hear about the steel tubing. It looks surreal, the tank sitting on that trunk... and I thought you were insane.


----------



## Gamezawy

scolley you said ( DO NOT buy tempered glass of any variety ) but why ? isn't it much stronger than normal glass ? and about making holes in the glass you can make holes in it then you order it to be tempered


----------



## mrbee2828

I know this is an old thread but I hope someone can chime in on this. I have been researching building my own glass tank for awhile now. I live in both FW and SW worlds and have been building sumps and overflow boxes for people for about year. I'd like to venture into glass and have done everything but order my panels. I'm actually waiting on my first quote. I use RTV for my overflows and sump baffles as well. 

This was already spoken to earlier but I don't really have a definitive answer. If I'm mounting the sides on the top of the bottom panel, do I need to cut the side panels 1/16th" shorter or so to allow for silicone? Thanks, I'd like to order the glass this week if the numbers are ok. My first venture is a small frag tank for coral. It's going to have 3/8" thick glass with machined edges and an external overflow.


----------



## Fletch

Yep, this story scared me. I really appreciate the time and effort you put into the troubleshooting so that others could learn some of the subtle lessons, without having to clean up 75 gallons of fishy water. I may still try building my own tank, but it will be much smaller. Maybe the same size as my shop vac.....


----------



## treyLcham

Just my 2 cents. I found the videos Solcielo lawrencia posted on my thread to be very helpfull if you are building the tank the way the bottom glass sits inside the vertical glass lay. http://www.plantedtank.net/forums/showthread.php?t=763002&highlight= I will be trying this out this week so wish me luck XD One thing i got confused with what wendle i think his account name is when he was talking on this thread is, when he said he left a like 1mm gap between each pain of glass did he just leave it that way to dry or did he after putting the silicone in push the glass snug against one another?


----------



## Rockfella

wendle said:


> one other thing i forgot to mention.
> when you are applying your silicone to the faces of the glass, don't drag the nozzle along the glass. cut the nozzle so the goop comes out at the same thickness as the glass, then hold the nozzle about an inch off the surface and keep moving at the right speed so the silicone hangs down and keeps laying onto the glass in a nice consistent worm. dragging the nozzle along the surface always leaves air bubbles in the glueline (which look terrible if you are building a bare-glass tank) and can't be good for strength.
> the nozzles are also made from a nylon that silicon doesn't stick to (for obvious reasons) so you don't want any residue of that particular plastic abrading onto the glass from dragging the nozzle along.
> this is probably the part of building aquaria that takes the most practice.


Nice pointer, but I think it needs practice.... a lot of it.


----------

