OT: Mopar plastic gas tank leaks;what to do?

If there is a civilian version for sale, we use a chemical for Missile seals that is known as Polysulfide, it says on the cans, "for fuel systems, tanks, etc. it is a two part chemical, like an epoxy, it sets in around 30 minutes, our version looks like fudge, smells like high solids paint, epoxy, ++.

I would think that the gas tank repair coatings could help, Por-15 makes one, I believe the key is to remove the traces of fuel prior to AND wait the alloyed cure time++