ply tank leaks

  • We are currently upgrading MFK. thanks! -neo
tthanatoss said:
My tank has been up and running for almost a year now, with no leaks or issues at all. I went with the liquid rubber option it was cheaper by far and very easy to apply. used 3M 5200 to seal the glass as regular silicone won't bond to the rubber. Only issue is that the rubber turns a brown color where it is submerged and it was very hard to get it to cure properly except in direct sunlight. It also never fully cures and even months later will stick to anything left sitting on or against it. Regardless I sealed a 250 gallon ply tank with about a gallon and a half and at $25 a gallon here in Canada that was about 1/10 of the price that expoxy would have cost me.
Epoxy is brittle and unless you can build a tank in such a way that it won't settle over time (just about impossible with construction lumber). We are literally talk about tons of water here. It is eventually going to crack in the corners. Remember most pond epoxy is designed to cover concrete. The only way to avoid that happening would be to use enough layers of cloth and epoxy resin that it would alone support the weight of the water without the wooden frame, ie..as thick as a boat hull. (Or build your tank and stand out of steel)
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have you tried the liquid rubber on a saltwater aquarium or heard anythign about how it will hold up in a saltwater tank?

i've read on zavlars data sheet that it is resistant to saltwater, but i don't know how true that is
 
Hate to admit it, but I had leaks too. My fault though. I failed to sand a corner between coats of epoxy and it failed within 2 weeks. I don't think you can see the inside corners on mine (in signature) but I filleted them just like you would a boat. In other words; I epoxied to the corner, then added a a trim piece ripped at 2 45deg on both sides to fill the corner then epoxied over that. This makes a MUCH stronger corner. Also, do not use construction lumber. 25 yrs in the business, I can tell you it will shrink, warp, crack, split, flip you the bird and cause all sorts of troubles. An aquarium with glass is a precise build; don't scrimp. I used solid Red Oak for a huge part of mine and 3/4" CDX ply.
 
so you don't think 2x4s and 2x6s from hoem depot will work well? i was thinking about using those to build the frames around the veiwing window and using 3/4inch ply on the inside so that the glass doesn't stick out and is flush with the plywood, the back wall i planned on going with 2x4s 6 inches on center and doign a coast to coast overflow at the top of the 2x4s. i was hoping the lumber would keep things from flexing to much and the plywood would keel the lumber from spreading and shrinking to much
 
I used CDX because it is rated "exterior" and cheaper than the prettier stuff. Simply means that the glue it's made with will not fail if wet. The C D part refers to the quality of the top and bottom veneers; if you want a perfect veneer you will need an A type.

The 2X construction lumber will probably work. For reference, an average 2 story house shrinks an inch in its first year from drying lumber! Some is much better than others; anyone in northern CA or OR should never use lumberyard 2X. Most home owner lumberyards carry what is referred to as SPF, it simply stands for a mixture of Spruce, Pine and Fir. If you know what you are looking for, the spruce is the most stable of the 3.

I used 1X2 Red Oak as studs, 6" on center. Also same for the floor/bottom. All the stud cavities were filled with R10 foam insulation.
 
tthanatoss said:
My tank has been up and running for almost a year now, with no leaks or issues at all. I went with the liquid rubber option it was cheaper by far and very easy to apply. used 3M 5200 to seal the glass as regular silicone won't bond to the rubber. Only issue is that the rubber turns a brown color where it is submerged and it was very hard to get it to cure properly except in direct sunlight. It also never fully cures and even months later will stick to anything left sitting on or against it. Regardless I sealed a 250 gallon ply tank with about a gallon and a half and at $25 a gallon here in Canada that was about 1/10 of the price that expoxy would have cost me.
Epoxy is brittle and unless you can build a tank in such a way that it won't settle over time (just about impossible with construction lumber). We are literally talk about tons of water here. It is eventually going to crack in the corners. Remember most pond epoxy is designed to cover concrete. The only way to avoid that happening would be to use enough layers of cloth and epoxy resin that it would alone support the weight of the water without the wooden frame, ie..as thick as a boat hull. (Or build your tank and stand out of steel)
Click to expand...

Totally agree. Liquid rubber has 800% elasticity and returns to 95% of its original form. I applied 6 coats on a piece of bond paper then after drying peeled off the paper and stretched it. I was so happy with the result I almost cried. :redface: Because of that I didn't bother to apply reinforcement cloth on the seams. But how did I miss reading the above poster's build? :wall: 3M 5200 is widely available here, fiberglass resin as a bridge between silicone and LR was a cool idea but I wanted to rubberize everything to make a seamless seal. Will definitely try 3M 5200 on my next build.
 
I got the materials from Home Depot. They also carry 3M 5200. The only thing I ordered online was the liquid rubber.
 
Can't you just liquid rubber the tank, and just do fiberglass only around where the windows would go...so silicone would stick?
 
hmm so just tape off the area where the silicone will go with the glass? or would it just be easier to get the 3m 5200 that will stick with the liquid rubber?
 
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