FWIW : old garages used to weld up rusty fuel tanks . They would remove the tanks and run an exhaust pipe into the empty fuel tank , poke a hole ( about 3/8'' ) into the uppermost part of the tank , start up the donor car . After a few minutes , braze , led or weld away . After finishing , they would fill in the man made hole and call it good .
I'm not sure if these were men or fools ?