Re: plastic gas tank
This stuff sounds to good to be true,
did the tanks need to be removed to use it?
How was it applied?
Tank sealers are used a lot on motorcycles.
I restore vintage bikes on the side (got 8 under my belt that I've completely disassembled and rebuilt), and though I've heard of many people who are happy using tank sealers, I'll never use them.
I tried once, followed directions exactly and was very cautious since the stuff is $40/kit and I didn't want to waste it. The muriatic acid in the kit (used to remove the tank's rust) ended up making the existing pin holes into real holes. It made other areas very thin, so much that it'd be dangerous to use. I rinsed it out (per the directions), dried (w/ a blow gun) and then put the sealer in. It looked nice, but still leaked, and in some areas, was peeling off.
After that incident, I use electrolysis to remove the rust and scale, rinse, then etch w/ phosphoric acid. I then swish around a gas/oil mix inside to prevent any flash rusting, and then seal it up for storage until the rest of the bike's done.
This applies to steel tanks of course, not aluminum.
The tanks should be removed if you want the whole interior coated, not just the bottom. Also, if it pools in the bottom, it might not set up properly due to being so thick.
For what it's worth, my boat came w/ a nice 20-gal Mirax steel tank w/ level sender & gauge. When I redid my boat, I replaced it with 2 orange poly tanks. Although the Mirax didn't leak, it just looked like trouble w/ all its surface rust.