theres gas tank repair that u can get where they use a plastic to seal the whole inside of the tank and when it dries is just like a plastic gas can i even saw a demo where they carefully cut the metel tank away after it was cured and showed us how durable the tank was after it was cured
look in the yellow pages for gas tank repair shouldnt be very expencive for such a small tank or go with the jb weld idea it might hold for awhile