I'm sure that almost all of us have encountered broken die-castings. Not unusual since some have a ductile-brittle transition temperature not far below room temp. Has anyone got any tips/tricks for welding die-castings of high zinc content alloys like Zamac (ZAMAK)? I tried once some time ago... TIG welding/argon/various tungstens/polarities/etc and all I got was a crappy weld because it would pop and spit out metal before I could even develop a real puddle.
I assume it was the zinc vaporizing before the other stuff (Al/Mg/Cu) was even halfway to their melting point. Being unable to weld inside of an atmosphere of 20 tons per square inch to keep the zinc from volatizing, I gave up. But I revisited this question last week when someone brought a GM tilt steering column to me that cracked when the 4 bolts deep inside backed out and let the wheel thump back and forth.
I know this stuff used to get soldered with a special Cadmium alloy solder (EXTREMELY dangerous/toxic) but that's out of the question. Anyone recommend different gas, particular tungsten, AC squarewave, AC sinusoidal, particular balance, glovebox atmospere?