i will start by saying i have seen this done with my own two eyes and i have also seen a barracuda gas tank getting a 3/4 inch line brazed into it shoot clear across the garage with a speed and quickness and dent a steel panel door
with that said
the guy who was doing it filled it with water and hooked up a shop vac to the filler neck on the output side so it was constantly pumping fresh air in but he was also soldering in at the bottom of the tank
i dont know
just be very carefull the good ole boys around here braze up there gas tanks on these open wheel racers all the time
but there also crazy and every now and again you here about one gettin lit up pretty good
hell try the epoxy and if it dont work then something else
how dumb would it be to empty it real good set it in the open yard and light it let it burn itself out
wouldnt all the flammable vapor be gone ???
as i type i am shaking my head i dunno!!!!
be carefull
