I've used that stuff, and it is really more of a gimmick and doesn't work. The only way you can really get away with is if you coat the inside of the tank.
Originally Posted by Lair
PPG makes a polypropylene primer that seals the pores on plastic gas tanks. I hope OP was aware of it pre-paint.
Edit: Metal tank, nvm then.
Last edited by B_Cyrus; 12-30-2012 at 11:12 PM.