# glass thickness for a 40 gal breeder rimless?



## dustbust_1 (Jan 17, 2012)

I want to build a 40g breeder rimless (36Lx18Wx16H) Would I be safe to do this with 1/4" glass? I will be using RTV 103 or 108 whichever is black.

I have an old 40g breeder lying around and im basically going to take it completely apart, clean up all the panes and reassemble it using the "stronger" silicone and not using the black frame.

Thoughts?

Ive done the research and iv read many different opinions im looking for someone who has experience with building tanks. It seem like a lot of info on forums is regurgitated information that someone has read somewhere else. Know what I mean Vern!

Thanks guys/gals


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## mstamper (Jun 5, 2012)

The biggest issue that has been talked about A LOT here and on other sites is the amount of flex that a tank has and that the reason for having a rim was to keep that flex in check. De-rimming a tank is possible, not always recommended. 

I think that 1/4" glass, without a top rim, is really pushing the envelope. From the other threads I have read, that thin of a glass will flex a lot. I do not think it really matters how "strong" your silicone is, the issue is with the deflection of the glass and what the glass tensile strength is, and how far it can flex before it cracks and then shatters and you are cleaning up 40 gallons of water, substrate, decorations, and of course fish.

I have seen 12x12x12 glass cubes that use 3/8" glass. There is not a lot of flex at that thickness and width of the glass. Just imagine glass 1/8" thinner and 36" long. That is a huge difference in deflection.

You can try it, just be ready for the clean up.


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## Bushkill (Feb 15, 2012)

OK, here's my 2 cents on this:

The shorter height of a 40B negates the need for a center brace because it minimizes bowing at 1/4" thickness. Hence, they don't have stock centerbraces, just perimeter.

I happened to have a 40B in the back seat of my car (don't ask, lol!) and went out to double ck that it's 1/4" and not 5/16".

So the trim on that tank does nothing to prevent center-bowing.

What it does do is enhance and preserve the integrity of the silicone bond at the upper and lower corners. 

If you've ever assembled a picture frame, think of the top and bottom trim as picture frame clamps.

If you're intent is to use the same components after tearing it down, I would suggest that you install bottom eurobracing and glass chevrons in the top corners of the thickest glass you can get cut for you. My guess is 3 inch "triangles" should work.

Momentive is def. the way to go here, and LOTS of masking tape to keep joints nice and clean since this is to be a rimless.

Also bear in mind that once you remove the trim, the edges will need to be professionally seamed to get to the clean look of a rimless as well as to make them safe to work with.


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## OVT (Nov 29, 2011)

ADA's 90P uses 10mm glass.

via Droid DNA Tapatalk 2


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## dustbust_1 (Jan 17, 2012)

The tank ran as a reef for 4 years with each corner of the frame cracked & separated. Ive recently taken the top frame off and the plastic is pretty flimsy so its hard to believe its there for structural support. Seems like it would bend with the tank if it bowed. The tank is sitting in my basement waiting for me to decide what to do with it.


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## Bushkill (Feb 15, 2012)

dustbust_1 said:


> The tank ran as a reef for 4 years with each corner of the frame cracked & separated. Ive recently taken the top frame off and the plastic is pretty flimsy so its hard to believe its there for structural support. Seems like it would bend with the tank if it bowed. The tank is sitting in my basement waiting for me to decide what to do with it.


Top and bottom trim has several purposes:

1. It does provide a rigid frame that helps prevent top and bottom corner seam separation. Note the "helps prevent" part. Tank seams, at whatever size tank, can and do fail at various tank ages with the trim intact. There are no airtight guarantees.

2. At taller tank heights, a center brace helps prevent center bowing, thereby preventing further stress on corner seams. They also facilitate the installation of glass tops and covers that now don't need to be 3 feet long in some cases.

3. The added integrity that one piece trim provides, lets manufacturers use thinner glass. Think of all the cost saving avenues here, there's a bunch.

4. It covers the most dangerous part of any pane of glass and eliminates the need to seam (polish) the exposed edges. More cost savings.

There's more, but all I'm trying to emphasize is that you shouldn't plan on the rimless route simply because the tank held water with trim that was broken and cracked at the corners. All I'm advocating here is that if it were my project, I would build in some peace of mind factors. If you're OK with tearing it down and reassembling it with Momentive RTV, understand that I'm absolutely not writing all of this to tell you you're wrong or making a mistake. There's lots of ways to achieve things like this.


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## Bushkill (Feb 15, 2012)

One thing I should emphasize is that though the plastic to make tank trim out of may appear flimsy, step back and understand the forces that it's meant to counteract when a tank is filled. Think in terms of tensile strength. It may not stand up well to being dragged across a floor or being picked up by the brace in the middle of the tank, but in most cases, it's pretty tough to get it to stretch on a horizontal plain. Can a piece of trim be poorly cast and fail? Absolutely.


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## dustbust_1 (Jan 17, 2012)

OK so possibly a eurobrace or Ive been tossing around the idea of a small wood frame to match a future stand.


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## DogFish (Jul 16, 2011)

I used 3/8" on my 40rimless 36x17.5x14.5




It's been the Goldfish/sump on my aquaponic system for 6mos. prior to that is was outside on my deck as a grow-uout tank last summer.

I might try 1/4" on a 40 rimless IF it was in a basement. I would not try it in a living space.


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## dustbust_1 (Jan 17, 2012)

Ya I think Im going to just re-silicone the inside, leave the bottom frame on (will be hidden with molding from future stand) and do a real wooden topframe. That way it will match the stand and hanging canopy. I think wood will be better than plastic anyways. I will have to oil and varnish the heck out of it. Oak is my first choice since its a cheaper hardwood with minimal flex and warpage. 

I really do like the rimless look but with a new baby on the way I cant see myself dropping money on an ADA or buying glass from our local shop and Building one from scratch (almost $300 which kind of seems high) SO it boils down to do with what I have or no tank.

I think seeing clean seams, a nice stand & canopy, and a nice oak rim will really grow on me. Besides rimless are a more modern looking tank where my house style is more oldschool classical.


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## DogFish (Jul 16, 2011)

If you're good with woodworking, you could run an Oak Dowel rod, front to back at the mid point to act as a center brace. Carpenter's glue and a finish nail running down through the dowel rod from the top of the frame would greatly increase the new rim strength. I would drill the frame and dowel rod for the finish nail pin so the Oak dent split on you. Maybe use a drill bit a little under sized.

Post up a thread in the DIY, looking forward to seeing your efforts.


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## dustbust_1 (Jan 17, 2012)

Im decent. The dowel would def increase strength but since the old frame didnt use a center brace (aqueon) Im going to skip it. I think running molding/trim on the top outside then laying a thin piece over the top covering the glass and outside wood (basically making an L shape) would greatly increase strength and lessen the flex since it will be fighting against about 1/2" of oak.

Im terrible at explaining things. Ill do a thread on the whole thing for sure.


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## DogFish (Jul 16, 2011)

I would look at the flex issue like this. I can flex a 36"L Oak 2x2" . I can not flex a 18" length of that same board. The center brace would in effect create two 18x18 squares. 

I do fully admit to be a DIY that overbuilds everything. :hihi:


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## dustbust_1 (Jan 17, 2012)

In that same argument I can flex and snap the original plastic very easy. The part that will give the added strength will be the top piece. So take that same piece of oak and flex it. Yes it bends and you can snap it. Now take a L shaped piece and bend it. It's a lot tougher.


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## JoeandCarrie (Oct 26, 2012)

If it is available to you, Teak would be ideal. A good oiled finished with a wax buffed in to pollish it up would make Oak work just fine though.

just my 2c


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## DogFish (Jul 16, 2011)

dustbust_1 said:


> In that same argument I can flex and snap the original plastic very easy. The part that will give the added strength will be the top piece. So take that same piece of oak and flex it. Yes it bends and you can snap it. Now take a L shaped piece and bend it. It's a lot tougher.


O.K. ~ Try this logic, if you're wrong....you're flooded. If I'm right or wrong my floor is still dry if you tank fails. :hihi:

Best of luck.
:icon_wink


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## jamesjkl (Oct 15, 2012)

DogFish said:


> Quote:
> 
> Originally Posted by dustbust_1
> 
> ...





_Posted from Plantedtank.net App for Android_


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## jamesjkl (Oct 15, 2012)

jamesjkl said:


> Quote:
> 
> Originally Posted by DogFish
> 
> ...


if you can ben a oak 2x2 more than a 1/4 inch in a 3 ft pc without standinf on the end i want a intro to you trainer


_Posted from Plantedtank.net App for Android_


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## dustbust_1 (Jan 17, 2012)

JoeandCarrie said:


> If it is available to you, Teak would be ideal. A good oiled finished with a wax buffed in to pollish it up would make Oak work just fine though.
> 
> just my 2c


Teak would be nice but Oak is more readily available around here. Im actually going to use a teak oil first 2 coats, sand, stain, outdoor Poly. That will hold up to any amount of water.

Ive used teak on making knife handles and it stands up to weather Very well.


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## dustbust_1 (Jan 17, 2012)

here is the rim I made. Trust me, with 2 hands you will not be able to break this. 

I will still do a months leak test.


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