Sealing a Fuel Sump

I bought a sumped tank that my car really doesn't need a few years ago from a nameless vender.

In the last year it would weep fuel from one of the plugged bungs on the sump. Recently it's gotten worse leaving a spot of fuel on the garage floor. Obviously not cool.

I assumed it was the plug leaking. Pulled it out, drained all the fuel cleaned the threads new teflon and back in. Still leaks. Looks to me it's leaking from where the bung is welded in. Cracked maybe? Dunno.

Short of a rad shop welding is there anything you can do at home? Otherwise I want to put a stock tank and 3/8 sending unit and be done. To bad I can;t find someone local to trade with who actully needs the tank.