# Epoxy for plywood tanks



## allanschon (Mar 25, 2007)

I'm in the early planning stages of building a series of plywood tanks, and I decided to figure out the waterproofing issue asap. I've seen a few other plywood tank threads lately; hopefully someone else can make use of this information.

I know that people have had luck with West Systems epoxy, and I've seen recommendations for epoxies, including sherwin williams brand "Epoxide HS Tank Lining and rustoleum brand "9200" system epoxy from the tank building pages at garf.com

I don't have a local source for West Systems, and the shipping isn't cheap. Apparently, both rustoleum and Sherwin-Williams have discontinued thier options.

So, off to the web... I came up with this: Macropoxy® 646 PW

I looks like it has some properties that make it beat West Systems offering. Firstly, it has a "Pot life" of 4 hours, as opposed to less than 30 min. Being able to take my time with the coating job makes me feel like I'd be able to take my time and get it done right, the first time. Of course, the trade off is that I'd have to wait up to 48 hours between coats. Also, as you can see in the data sheet, Macropoxy is specifically designed for potable water, so we know that it doesn't leech toxins once it's cured. 

Let me know if you have found, and had success with, other options. I'm a few months away from needing to actually buy waterproofing materials, so I've got plenty of time to change my mind.


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## frogparty (Dec 27, 2007)

I have been thinking about a plywood build lately as well. So many different things you can do. Hope to see some of your progress, mine is still in the dream stage, especially cause I have to move in a couple months I just found out.  I have seen some of the most amazing builds on Monster Fish Keepers in their diy section, some thousands of gallons! home made shark tanks. Lots of info on product choice, and more. Makes me want a 1000 gal viv


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## JoshH (Feb 13, 2008)

This is what I use, inexpensive and designed to build commercial aquariums. Available in several colors, I use it to build the actual tanks and to make rock backgrounds.

Aquatic Eco-Systems: Sweetwater® Epoxy Paints, 1 Gallon


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## frogparty (Dec 27, 2007)

nice! I love your backgrounds


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## psychemjr (Jan 6, 2008)

Drylok would be the way to go. It is totally safe once dryed and will hold up to high humidity. Drylok was originally designed for Sea World's tanks/ It is best suited for application on cement. But it holds just fine on plywood and you can get it at home depot at $20.00 per gal


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## allanschon (Mar 25, 2007)

JoshH, thanks for the tip. I'll keep it in mind. Hopefully I can find a local source for the Sweetwater product. For some reason it never occured to me to look at products designed for pond building... There have got to be a couple of stores in the area that carry similar products. 

One thing that has been worrying me is the possibility of an epoxy coating cracking if the plywood flexed. The tank I have in mind is 48"x18"x24", which is small enough to move, if needed, but also large and heavy enough that unless I cast it out of steel reinforced concrete, I have to account for some amount of material flex. Now that I'm thinking along the lines of pond building, I've also found HERCO No. H-55 Neoprene Rubber Coating. Since this coating is rubber based, it should be more tolerant of a tank racking slightly during transport. Again, since it is designed for aquaculture, it should be safe. It ain't cheap, though...

I've considered Drylok, but the possibility of chemicals leaching out worries me. Also, according to thier website, thier warranty doesn't apply to applications that are constantly underwater. This tells me that I could have durability issues with it. It's bad enough if your background rots after a few years, and the tank has to be rebuilt, but it would be really unpleasant if the tank itself started rotting and had to be thrown away.


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