[dr wethumb]

I am looking for some comparison's for building techniques on plywood build's fiberglass seem's to be the ticket for an inexpensive start and a couple of coat's of drinking water grade marine epoxy paint.

What's the effect of marine epoxy resin or drylok vs the above vs price i tried using the paint alone and the base of a 100 gallon cracked under the pressure i built a 150 using fiberglass resin 2 part epoxy gel coat and a couple of coat's of potable marine paint( mostly to fish safe)
the build was costlty this way but there was not a single issue.

Fiberglass resin alone (waxed or unwaxed toxic) isn't completly waterproof and contain's chemical's that can be harful to fish (after further resarch) Drylok is not easily availible in my area and marine exoxy resin that's a potable grade seem's to be highly costlty i have also tested several alternative's that don't work and marine epoxy resin has also proved to be diffucult to find locally.

 

[Mcdaphnia]

I'm curious about the methods you mentioned that didn't work, and how you determined they failed. It is harder to tell that a tank is OK than just filling it with water and looking for leaks. If you make a plywood box for your tank and fill it with water with no painting or waterproofing at all, it will hold water, just not for long term.

Finding good cheap materials that work is always a DIY dream, one that often remains just a dream, but don't stop looking.

 

[dr wethumb]

When i mentioned a method that did not work it did of course hold water for about a week but it may have worked if i did not cheap out on the wood so much it was an osb plywood tank at a 100 gallons even though i patched the joints and used marine epoxy paint (alone).

The base on the outside cracked while the inside appeared to be intact water seeped into all the wood and softened it up so i scrapped the whole thing after it started to leak in my living room.

 

[BrianNFlint]

I dont think I would test such ideas in my living room.

You can buy fiberglass resin in large quantities, then use a thick fabric bought from a fabric supply store.. You will save alot of money doing it that way.

 

[98dak83cam]

Get epoxy resin, not poly resin. I got my epoxy resin at http://www.uscomposites.com/epoxy.html

About 65.00 a gallon, it took a few gallons to do my 1000 gallon aquarium. It went on easy, I had to leaks, and it is flawless to this day. I also fiberglassed mine, even though I don't think that it is totally needed. There are really two options - you can take a little extra time when you build it and use the epoxy resin, or you can go the paint method which may involve doing a re-coat down the road. I prefer to look at my fish tanks rather than work on them. I must admit building them is more fun than anything though!

I think your original problem was structural however, don't use OSB, it is really weak stuff. Go with a good outdoor grade 3/4" plywood or a laminated product if you can get it locally.

Good luck :thumb: