here's a topic i don't remember seeing.
i had a dent in gas tank of the demonstrator cub that was probably 3/4 inch deep and 3 inches in diameter. It's ugly to use that much body filler, so i needed to get it out.
suggestions from a close friend and Fordson collector ranged from cutting the offending dent out - reshaping it - rewelding it back in, to drilling a hole in the bottom to insert a rod to tap out the dent. both good ideas, but kind of intrusive.
this is what we came up with..
first, the gas tank has been in the electrolyte tank, so no danger remained from gas fumes.
we welded a nut onto the gas tank with the mig, then heated to surrounding dent from the outer edges first as i pulled on the attached rod. as the dent pulled out, heat was applied more toward the center. You need to heat the dent nice and red all the way around as you do this.
we left the dent a little negative, so it could be shaped with body filler.
Viola! fast and easy! it took longer to write this than the actual repair. and no holes to fix