# DIY 55gal plywood aquarium built from a wooden medical crate



## yelostoner (May 7, 2010)

Hi there, first off this is my first post here but I'm not a newb to the aquarium world....just to building plywood ones...so here's my story

I have in my possession a reinforced plywood medical crate, in a "tank" orientation it's 20.25" tall by 34.5" wide by 24" deep (these are external dimensions, internal is 18"x32"x22"), which works out to almost exactly 55 gal assuming that all space is used inside (not likely), the crate is built with 3/8" plywood reinforced with 1x3's around the edges with the long panels having a 1x3 brace in the center of the panel as well. each panel is individually constructed and all are nailed together (that needs to change).

I've tried to do the math to decide if this crate is strong enough to support the weight of the water that will be inside once the nails are replaced with screws and it's been epoxied/fiberglassed.

I know plywood builds are usually reserved for BIG tanks, but...i have this crate, I'm restless for a new project, and I WANT A NEW TANK.....

Any and all opinions are welcome....


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## Mcdaphnia (Dec 16, 2003)

It should be OK. Thinner plywood than usual, but reinforced edges. If you are fiberglass it, use a couple layers of matt or cloth between coats. There are additives you can use on the first coat to adhere it into the wood and on the final coat to make it harder.


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## newfisher (Dec 20, 2008)

What are those additives?


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## Mcdaphnia (Dec 16, 2003)

newfisher said:


> What are those additives?


 When you choose a system of fiberglass the available additives will be explained for their brand.

http://www.westmarine.com/1/3/epoxy-add ... fiberglass

http://www.dowcorning.com/content/plasc ... glass.aspx

Although I still like PalGard, it's not considered DIY.


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## newfisher (Dec 20, 2008)

But none of what you listed are for "use on the first coat to adhere it into the wood and on the final coat to make it harder".

What you've listed are BottomKote coatings that are full of biocide (yikes), new but very costly West System epoxies, and epoxy based paint that is okay only for incidental food contact. But these aren't additives, or products that can do what you claim. The Dow Corning site does advertise additives, but they're epoxy molding compound, flame retardant additives, glass wetting agents, and such, which do not do what you claim and which are way beyond the realm of any DIY.

I'd like to know specifically what epoxy additives you're referring to that can be used to make first coats adhere to wood, or final coats harder, and what epoxy formulations those additives are compatible with, as these might be very useful for aquariums and other applications.


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## Mcdaphnia (Dec 16, 2003)

newfisher said:


> But none of what you listed are for "use on the first coat to adhere it into the wood and on the final coat to make it harder"
> ......
> I'd like to know specifically what epoxy additives you're referring to that can be used to make first coats adhere to wood, or final coats harder, and what epoxy formulations those additives are compatible with, as these might be very useful for aquariums and other applications.


I've found them in the past when I didn't need them, but looked and didn't find them online anywhere I checked today.

Does someone know where to find fiberglass additives to bond the first coat to wood and harden the last one? I have a tank that I have to recoat that was built about thirty years ago, summer of 1979. The PalGard coating is still not leaking but it's worn right through in places where hard corals attached and grew for years. Why it doesn't leak I don't know. but before refilling it I will reseal it and recoat it. I guess the additives are not 100% necessary, but I would like to be sure the tank coating lasts this time. :wink:


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## GeriJo (May 13, 2010)

I know it sounds crazy but i would talk to someone who owns an upscale body shop... they use fiberglass for many things & you may be suprised at what they could tell you.


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## yelostoner (May 7, 2010)

GeriJo said:


> I know it sounds crazy but i would talk to someone who owns an upscale body shop... they use fiberglass for many things & you may be suprised at what they could tell you.


funny you should say that, I'm a body guy by profession and I just got done with the inside of this tank (i decided to go for it....), I used standard grade automotive body filler mixed with a flex additive (Rage Gold and Icing) to prep the inside surfaces, primed the inside of the box with urethane primer and applied three coats of Atlantic Blue Pearl (a Chrysler color), then about 6 coats of urethane clearcoat, waiting for the surface to tack before applying the next coat (I used a 30% reduction on the clear as well as a flex additive). After it dried (about 12hrs for it to be handle-able) I siliconed all the seams and installed the 3/8" glass I'm using, I let the silicone dry for 3 days and it's currently sitting in my shed full of water.

I don't see any reason why this box shouldn't hold water forever, clearcoat and silicone are designed to be in contact with water 100% of the time, the silicone is only there to make sure I don't have any pinholes at the seams


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## GeriJo (May 13, 2010)

My favorite color to use is Plum Crazy Purple.... I think that would look awesome in a tank too. I can't wait to see some pics. opcorn:


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