"Welding" Unknown Pot Metal (2025 Update)

I've got a part I'd like to repair if for no other reason than to be able to do it. The value is much lower than my time.

It’s a die cast mystery alu-zinc part. From what I have read the BlueDemon/AlumiWeld/MuggyWeld/DuraFix class of aluminum "brazing" rod is the way to go due to its low melting point. I've used Muggy Weld and Dura Fix rod to bond known "aluminum" in the past. Usually 6061 or 5052. It works, but you pretty much have to be able to lay down the entire repair at once and leave it to cool. I may not be able to that with this part, but that's not where I ran into a stop on this part.

The way most of these rods is used is to heat the metal until its hot enough to melt the rod. Push it around until it wets out where you need it and let it cool. On this project the base part started to melt before it got hot enough to start melting the rod. I wiped wth acetoe and brushed thoroughly first. Same way I would prep to mig weld aluminum. I told the person who asked me to repair it (my dad) and he said he expected that and not to worry about it. Still I'd like to find a way if at all possible. It bugs me. I read one website were a guy claims to be able to weld any kind of potmetal with TIG, but the only other references I found was the same guy spamming his services on various web forums.

I took it over to a buddy of mine who does a bit of TIG welding and he gave it a go. He tried low current with AC TIG and the max set at 75 amps and used the foot pedal to start lower. The first thing I noticed watching was the arc was red. We double checked on a piece of known aluminum and got the expected blue white arc. The other thing is the arc danced wildly. Back to the aluminum and a normal looking arc. The other thing was it just didn't seem to puddle at all. When he walked the pedal a little bit higher it just blew out metal.

We still don't know what it is, but we turned on all the fans and exited his shop after that to let the smoke clear... and there was smoke.

Its going in the dumpster I think.

Old timers used buttermilk, even heard a story of some welders refusing to weld galvanized with out their daily ration of buttermilk. Today it is very hard to find buttermilk that is not low fat. AFAIK the fat is what helps mitigate the fume fever not the milk. So 4% whole milk is the modern substitute.

A few years back had a nice little side job welding galvanized. Did it outdoors with a box fan suspended about two or three feet behind my head. No mask... Tried the whole milk a few times and skipped it others and could not tell a difference.