will this be safe for fish?

[CJH]

what do you mean? im kind of ignorant to the epoxy thing. I only need about 1 gallon to cover the area im painting

There is a lot of confusion about this in the fish trade so you're not alone.

Basically when it comes to sealing wood for aquarium use there are two types of two-part epoxies. Oversimplification but we'll stick with that.

The first type is 100% resin systems that have no solvents. West System, System 3 and the Raka mentioned earlier are examples.

When you use a gallon of these on a surface the result is a gallon of hardened epoxy. In other words, these are 100% solids.

Most of these are essentially clear products but they can be tinted for color.

Epoxy Paints are like the product in your first post in this thread and the Sweetwater product. They are a mix of epoxy resins, pigments and solvents.

When applied and the solvents evaporate and the resin cures you are left with only the solids. So in the case of the Sweetwater product you have 71% of a gallon left on your surface.

And since coat thickness is important with plywood aquaria it is important to compare percent solids when comparing price.

The nasty, lingering odor of epoxy paints aside, they are very easy to work with. They are similar to oil-based polyurethane to work with. The solvents help them flow out and help subsequent coats burn in, provided they are applied with the recommended window.

I have applied gallons of epoxy paint and hope I never have to work with it again. I just can't tolerate the solvents. Same with polyester or vinyl ester resin.

 

[AndrewMack]

So which one do you recommend going with? and I thought resin wasnt 100% water proof?

 

[CJH]

I thought resin wasnt 100% water proof?

The basic polyester resin you find in automotive stores is what's not 100% waterproof. Marine epoxy resins are.

So which one do you recommend going with?

Answer a few questions first:

1) Will your project require any fiberglass cloth, mat or roving in the corners or along seams?

2) Will you be sealing this tank indoors or outdoors?

3) What is the size of the project?

So you know where I'm going with these questions, I would recommend a 100% resin if any fiberglass needs to be applied and if the project is going to be sealed inside.

The size of the project is not necessarily so important but in general smaller projects are less likely to need fiberglass. And they can be carried outside so the solvents in epoxy paint are not as big of a deal.

 

[Fishyfan]

I used pool paint to paint the inside of a fiberglass pond, fish have been in there for years and are doing fine. I'm not sure how well it would work on plywood tho...

 

[AndrewMack]

I would prefer to paint the tank inside but due t fumes i had plans on moving it to the porch or this part of the project. my tank is roughly 300g

 

[CJH]

I would prefer to paint the tank inside but due t fumes i had plans on moving it to the porch or this part of the project. my tank is roughly 300g

If you plan to use any fiberglass then I would go with the Raka epoxy. I only single them out because they are in Florida and because they have a good reputation for a good product at a good price. My guess is that you can find other marine epoxies locally in Florida as well but that they will be a lot more expensive.

If you don't plan to use any fiberglass, then you can use either marine epoxy or epoxy paint. If you go with paint then I would choose the Sweetwater Paint since it is distributed by an aquaculture company, it has a high percentage of solids and because the company is in Florida, which should save you hazardous material charges.

Whether you need fiberglass or not depends on a lot of things. It does add significant cost not only due to the fabric cost but also due to the fact that more resin is required to wet it out.

Really, the choice is yours. If you're 300 gallon is tall and lacks external framing I would be inclined to go with epoxy and fiberglass.

If it's 24" tall or less and has external framing then epoxy paint should work fine.

It's possible the Sweetwater can be used to wet out fiberglass, I'm not sure. You would have to check with the company that makes the cloth you get.