Sonny you're NOT gonna 'set off' the fuel tank..you really only have that problem with gasoline tanks. The JB repair won't last,you'll be pullin it out again..I'd wash it out with water(and you really dont even have to do that) and then run shield gas from a MIG welder into it for 10mins or so, even that is really unneccessary...Clean off any exterior coating or paint then MIG it or braze the holes up, then rinse out with 1202 (Diesel)-use that same rinse diesel to check the pinholes for leaking..you'll do fine. Ive welded and cut on diesel fuel tanks for 20 yrs without ever one 'going off'..Ive even seen welding done on gas tanks in cars with gas still in them..no big blast,no fire either.
Welding up gas tanks
