one part or two parts epoxy paint?

[Luis]

is there any difference if I paint the back of my plywood tank with one part or two parts epoxy paint?

I've heard that both are reef safe. I just wanna be 100% sure.

thanks.

 

[Fl_Seagull]

One part epoxy paints will likely fail. They are not true epoxies.

I have not heard of long term success with anything short of two part epoxies.

Two part polyuerthanes (sometime confused with epoxies) will not work. They will fail by blistering during longterm water soaks.

 

[Fl_Seagull]

Sorry .

I may have miss-understood. If you're not painting the inside of the tank almost anything will work so long as it seal the wood.

I would recommend staying away from oil finishes, exterior latex and exterior stains to avoid possible problems. Oil finishes since they may take along time to fully "cure." Exterior latex and exterior stain often contains chemical to stop mildew.

Other than that, almost anything will work where you're not soaking the wood.

 

[Luis]

Thank you Seagull for your replies.

I'm going to paint the inside of the tank.

I went to HomeDepot and I found one part epoxy and two part epoxy acrylic paint. So I have to buy the one that is two part epoxy acrylic paint.

It does not need to be marine epoxy as long as it is two part epoxy.... am I right?

Thanks

 

[Fl_Seagull]

I found myself looking over the choices at HD myself 6 months ago.

The more I looked, the more confused I got.

I ended up buying 2 part epoxy pool paint from a local "pinch-a-penny" pool supply.

Let me try to contact a friend who is an editor for a "Composite Fabricator" and ask a few questions.

 

[Fl_Seagull]

I manage to contact my friend.

Is this the water-based epoxy paint (sorry could not get to HD to check for myself)?? Water based epoxy is not generally recommended for water soak environments

If it is solvent based it will work.

The first coat should be cut 25% with toluene and used as a primer. Let the toluene flash off and apply the next coat full strength while the surface is still tacky (~4 hours, less if its hot).

This will let the epoxy soak into the plywood and insure a strong bond. It also strengthens the wood surface.

I recommend 3-4 full coats. Even if you sand the plywood, I would allow the 1st full coat to cure 48 hrs and then sand. The 48 hrs to insure the coating has cured and that it won’t clog the sand paper (as fast). The sanding is to take any raised wood fibers down. Drips and runs are a problem but can be minimized by letting the paint set for 10-15 mins before using. I could never eliminate them. Just try to address anywhere they may interfere with the sealing of the front glass or appearance. The 3rd and 4th coating I tend to apply when the bottom coating is just tacky (~4hrs again) to insure a good bond between the layers. Others have had good success with sanding between all layers.

Just for reference: The average cost WHOLESALE cost of a high-quality, 2-part epoxy paint is ~$42 for 2 gal kit. Lower priced kits are often not “100% solids” based.