4300 Gallon Plywood Build (3600+ Take 2)

[cvermeulen]

There's no question about using epoxy resin. I'm sold on that for certain.

Why? It seems to me the cons outweigh the pros.

Pro - it sticks better to more things. But... you don't really care. If you're going to sheath the entire inside of the tank it will be like a hard, one piece liner. What does it matter how well it adheres to the walls? Also, I doubt even epoxy will bond well to the permadri. If you're going to sheath it with 1/4" ply first, then polyester bonds plenty well to wood products, particularly if they are very dry.

Cons: More expensive, Longer working time, Typically too hazardous to spray, Long cure time, Requires more precise mixing (if you screw it up it won't cure), Typically UV sensitive, More difficult to clean up (In my experience).

My 600gl has been up and running for 2 years with a fiberglass and polyester coating - zero sign of delamination, leaking, or deterioration. Pleasure boats are typically made from a plywood and polyester FRP construction, and they have a typical lifetime of water and intense UV of 20 years or more.

 

[cvermeulen]

Also, AnythingFish's 8000gal plywood tank is done with polyester. I haven't looked in on it lately, but it seems to me that would give Fiber Reinforced Polyester the best track record known on this site. I also installed an off the shelf 18,000gallon FRP water tank at one of my facilities a couple of years ago; it's a pretty well tested material for water storage.

 

[nolapete]

Polyester resin is NOT fish safe and has to be top coated.

 

[nolapete]

Pete's build is a mystery to me as well. As many coats as he applied with the LR I can't believe the LR is the issue. I am pretty sure it has something to do with the seal around the viewing window. Of course, when you are dealing with that much water and that kind of pressure I guess anything is possible.

Ross, I don't know how you can say that. The window is sealed on 3 sides and water has never come through anywhere near the window. The 3/4" seal on the back of the window that is covered by the 2x6 makes it very unlikely that water is getting anywhere near it.

I can't explain it either, but as Jonathan can tell you, leaks are mysteries that aren't very easily solved. Look at what VL had to go through with his. He tore out the windows at least 2 if not 3 times? If I remember correctly, it was not the Dow 795 that was the problem. Trust me it pisses me off every day when I come home that I can't figure out where the leak is and don't have the expendable cash to redo the coating and the fact that I spent more on Permadri than it would have cost me to fiberglass the whole tank.

Rubber Coat, Pond Coat, and a number of the other Permadri products are the same product (according to my distributor) just marketed under different labels for different markets. Permadri will neither confirm or deny that statement. I used some of both in my build.

 

[nolapete]

Never did hear back from the Max ACR guy.

 

[cvermeulen]

Polyester resin is NOT fish safe and has to be top coated.

Pete, please stop spreading this misinformation. Many people have polyester lined tanks with fish in them. Mine has been in service for 3+ years.

[Edit] If you are that paranoid you could topcoat with sweetwater or something similar and still be cheaper than epoxy composite.

 

[cvermeulen]

Sorry, it seems I've been a bit blunt on issues like this lately. I'm not trying to be a snot about it or anything; it's a bit of a sore point for me.

I originally planned to use polyester with fibreglass to seal my first build, as it was cheap and easy and I was familiar with it, but I was told by many people that it wasn't fish safe. The result was me using a more expensive product that ended up cracking after a few years. I've since learned of many people (including anythingfish's epic tank) that sealed with polyester without issues, and built my own tank with polyester products without issues. It irks me to see people making statements like the same ones that misled me years ago. Particularly someone like you Pete, who DIY people tend to listen to.

 

[JohnG]

The information on polyester resin being fish safe is at the very best uncertain, I for one will be sticking with epoxy resins which I know are fish safe. I don't know what you keep cvermeulen but I keep stingrays, which are much more sensative to anything leaching into the water than most fish are. Personally I would rather spend a bit more and not have to be paranoid if I am poisoning my rays.

There are plenty of epoxy based products on the market that explicitly say they are fish safe and designed for aquarium/pond building, I do not know of any polyester based products that say the same, do you?

 

[cvermeulen]

The information on polyester resin being fish safe is at the very best uncertain, I for one will be sticking with epoxy resins which I know are fish safe. I don't know what you keep cvermeulen but I keep stingrays, which are much more sensative to anything leaching into the water than most fish are. Personally I would rather spend a bit more and not have to be paranoid if I am poisoning my rays.

There are plenty of epoxy based products on the market that explicitly say they are fish safe and designed for aquarium/pond building, I do not know of any polyester based products that say the same, do you?

1) The information is sketchy because people insist on telling everyone it's not fish safe. I've not been able to find a single example of someone doing a FRP tank and having problems.
2) If your approach is to only use materials certified by the manufacturer as "fish safe" then I understand that, but that rules out a number of the products like GE silicone, Krylon Fusion, Zavlar, Etc. that are well accepted in this community.
3) My point isn't to poopoo anyone not using polyester - I'm going to use epoxy myself on an upcoming build for a myriad of reasons. My point is people need to stop screaming and waving their arms every time someone mentions polyester, as it has been tested fairly extensively and shown to be "Fish Safe" enough for most of us, and it bears many significant advantages to epoxy and similar.

[Edit] Also, like I said, if leeching is really a concern keeping you up at night, a couple of coats of sweetwater or some similar "fish safe" product could be done over the FRP and still come in cheaper than doing the whole tank in fiber reinforced epoxy composite.

 

[JohnG]

1) The information is sketchy because people insist on telling everyone it's not fish safe. I've not been able to find a single example of someone doing a FRP tank and having problems.
2) If your approach is to only use materials certified by the manufacturer as "fish safe" then I understand that, but that rules out a number of the products like GE silicone, Krylon Fusion, Zavlar, Etc. that are well accepted in this community.
3) My point isn't to poopoo anyone not using polyester - I'm going to use epoxy myself on an upcoming build for a myriad of reasons. My point is people need to stop screaming and waving their arms every time someone mentions polyester, as it has been tested fairly extensively and shown to be "Fish Safe" enough for most of us, and it bears many significant advantages to epoxy and similar.

[Edit] Also, like I said, if leeching is really a concern keeping you up at night, a couple of coats of sweetwater or some similar "fish safe" product could be done over the FRP and still come in cheaper than doing the whole tank in fiber reinforced epoxy composite.

I can't disagree with any of your points. Using sweetwater epoxy paint over a poly resin would eliminate any risk and would save some money. I used that paint anyway on both my ponds just to get the color I wanted.