# De-rimming a 50-gallon tank in 25 minutes



## hydrophyte (Mar 1, 2009)

I snapped a few pictures while doing this quick job in preparation for my next tank project, a riparium display featuring _Synodontis_ catfish. I started a tank thread for this one over in Tank Journals & Photo Album . (http://www.plantedtank.net/forums/tank-journals-photo-album/96449-catfish-riparium-40-breeder.html).

Here is the tank that I'm using for that setup.










My intention while starting out was to remove the top plastic rim. One might ask: Why would I want to wreck this perfectly good tank? I intend to plant it as a riparium setup with a pendant light fixture and an open top. The plants will grow up above the top of the tank, and the rimless aquarium will create a much more appealing display with unobstructed views of the emersed foliage and the water's surface. The tank will be filled to only about 3/4 of total depth and there will be several inches of seam on each corner above the water line. I hope that the tank thus filled will be strong enough to resist very much glass deflection and failure of the silicone seams. 

I was going to chalk this up as a success if I could avoid a trip to the hospital emergency room, but I wrapped it up with no trouble at all. On the advice of another member of my local fish club I learned of a smart way to remove that top plastic rim. Here is the list of the items that I used:


50-gallon Aqueon aquarium
block plane
snap-blade cutter
safety glasses
[strike]a couple of beers[/strike]
After giving it a second thought I struck item #4 from the list. I figured that it wouldn't taste so good in combination with the panes of glass and sharp blades.










This rusty old plane was out in the barn. It looks like a fine tool for contracting tetanus, and it's a lot bigger than what I probably needed. We have a newer plane around here somewhere, but I couldn't find it. This one has a dull and chipped blade, but it worked fine with the soft rim plastic.










I used the plane to remove the plastic all around the top outside edge of the rim until reaching the silicone sealant occupying the void between the rim and the top edges of the glass panels. I was careful to not plane any deeper than this, as the plane blade would have surely chipped the glass.


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## CL (Mar 13, 2008)

Hey, this is a cool thread! I'm sure you get tons of questions about derimming tanks. I know I did when I had a couple of journals for derimmed tanks. :hihi:


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## hydrophyte (Mar 1, 2009)

(continued)

After separating the rim into outside and an inside I was able to pull it away from the glass in several spots. Silicone sealant adheres very well to glass, but makes a very weak bond with most kinds of plastic. However, I found the rim to be holding tight at each of the corners. I used a snap-blade cutter to slice between the silicone and the glass. This is not a recommended way to use one of these cutters, as the blade can snap and send sections flying through the air, but I worked slowly and with extra care. It is a good idea to wear eye protection when doing any kind of cutting work.










I had imagined that I would have to cut through it with a saw blade in order to pull it away from the tank, but the outside piece of the rim just popped right off. It took some additional slicing with the cutter and careful pulling, but I was able to coax the inside piece off in just a couple of minutes.










Here is the tank sans rim and with the two pieces of plastic. I had placed the bag of pool filter sand inside the tank to prevent it from sliding around so much on the bench-top as I worked. Much of the painted background came of with the rim. It had occurred to me to try to save the background and patch it up with some more paint, but it will look more tidy if I just remove the old paint and apply again.










One thing that had me a little bit nervous was the condition of the top edges of the glass panels. I had wondered if one or two panels might have been slightly taller than their neighbors. I was relieved to see that all four corners were flush and the glass edge was in good shape.










Removing the plastic rim was an easy job, but a more demanding part of getting this tank ready to go will be scraping of the excess silicone and repair of the top edges with additional clear sealant. It might take a couple more hours of careful work to wrap this up and get the tank ready for setup in its new spot.


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## speedie408 (Jan 15, 2009)

Good stuff hydro. You forgot safety gloves. Recommended if you're working with blades of any sort. But then, only wussies care so nevermind 

I'm sure you'll be posting more updates as you go, so keep the updates coming.


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## CL (Mar 13, 2008)

I would just watch out for the glass bowing out. 3/4 full is still almost 38 gallons of water.


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## hydrophyte (Mar 1, 2009)

Yes that's a good point. I had planned to fill it slowly and watch what happens. I hope that I can get it to at least 2/3 full (~33 gallons). I might still consider some sort of reinforcement--such as short strips of metal bent 90 degrees, and glued in place--for the top corners.


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## smoq (Feb 19, 2008)

hydrophyte said:


> Yes that's a good point. I had planned to fill it slowly and watch what happens. I hope that I can get it to at least 2/3 full (~33 gallons). I might still consider some sort of reinforcement--such as short strips of metal bent 90 degrees, and glued in place--for the top corners.


Nice thread
Four stainless steel corners would look neat IMO. 
It's ridiculous what we have to do to make our tanks look like the ones Europeans and Asians would simply buy in stores:icon_sad:


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## hydrophyte (Mar 1, 2009)

My brother is a metalsmith and he might even be able to put together some handcrafted with nice material for me. I will mention it tomorrow during Turkey Day.


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## Hoppy (Dec 24, 2005)

My bet is that the corners won't need any reinforcement, as long as the tank is less than 3/4 full. That is both because the lower water height reduces the pressure on the glass, and because the unfilled portion of the glass pieces will reinforce the lower portion. Add to that my belief that manufacturers base their glass thickness on not having a rim, then they use the rim for a safety factor. Of course the taller the tank the more risk is involved, and this is not a tall tank.


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## smoq (Feb 19, 2008)

Hoppy said:


> My bet is that the corners won't need any reinforcement, as long as the tank is less than 3/4 full. That is both because the lower water height reduces the pressure on the glass, and because the unfilled portion of the glass pieces will reinforce the lower portion. Add to that my belief that manufacturers base their glass thickness on not having a rim, then they use the rim for a safety factor. Of course the taller the tank the more risk is involved, and this is not a tall tank.


Yeah, you are probably right, I just thought about how nice would steel corners look Maybe your brother can make a steel brace for your tank instead to prevent bowing.


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## hydrophyte (Mar 1, 2009)

smoq said:


> Yeah, you are probably right, I just thought about how nice would steel corners look Maybe your brother can make a steel brace for your tank instead to prevent bowing.


You could do a lot of cool stuff with custom metal hardware pieces as braces and rims and so on for tanks.


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## MoonFish (Feb 12, 2006)

It hurts to see that old plane in such rough shape! Yeah they are heavy but that one is just used to flatten a fairily large workpiece.


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## hydrophyte (Mar 1, 2009)

The barn out at the farm is packed with old antique and vintage stuff like that plane--all rusting or otherwise suffering water damage. I wish that I had the time and means to go take care of some of it. Maybe if the economy improves it will be more feasible to go and try to organize some of it and arrange to sell it off. I can't imagine that it would sell very well the way things are.


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## Green Leaf Aquariums (Feb 26, 2007)

hydrophyte said:


> The barn out at the farm is packed with old antique and vintage stuff like that plane--all rusting or otherwise suffering water damage. I wish that I had the time and means to go take care of some of it. Maybe if the economy improves it will be more feasible to go and try to organize some of it and arrange to sell it off. I can't imagine that it would sell very well the way things are.


Keep your tools! Dont sell them! Even if you dont know how to use them, yet


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## hydrophyte (Mar 1, 2009)

I just don't know what I would ever be able to do with all of that stuff. We live in a small house in town but the farmhouse and barn are literally stuffed up to the ceiling with old tools and furniture and you-name-it.


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## hydrophyte (Mar 1, 2009)

I have been moving fish and stuff around and now I am about ready to set up this 50-gallon. I should have some photo updates soon.

I am looking for opinions on one important point. How much water do you think I should put in it? I think that I am safe to fill this newly de-rimmed tank to 3/4 full, so I mostly have aesthetics in mind for this choice. I need to select an option now because I wish to paint the rear pane with black for the portion that will be underwater, leaving just the plain glass for the abovewater portion. The tank will be positioned against the wall so I won't really be able to apply the paint after set up. Here are the three options that I have in mind for positioning the waterline:


3/4 full
2/3 full
the golden section, with the greater portion being the underwater area


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