Welding Tips and Tricks

This is my second time coming across this metal and this time I remembered to ask you guys.

Both times I was fixing a broken piece of old shop equipment. First time was a cracked block from the end of a leg of a floodlight. It was very light and the crack showed a fine crystalline structure. It's not magnetic (or that I could feel) so I assumed it's aluminum. The moment I light up on it, it's like pouring acid on foam, except add tons of black soot that instantly coats the torch cup, and sprays silver sediment all over the part. I'm using a Dynasty so I can light up at 1 amp and no matter how low I go, even just from the HF start, it would do this.

This time, I wanted to fix a crack in a knob of my Delta bandsaw rip fence. Same thing, light up, POOF.

What is this stuff and is there anything I can try and do? Can it be tin??

Ugh why is my memory so useless, I'm already screwing up the story.

Correction: the metal IS faintly magnetic, which is why both times I started out trying on DC but I did later try AC for sanity's sake. The faint magnetism led me to believe it might be some low grade stainless. After that I had no idea.

I am just a new guy when it comes to welding but I would guess it's some super cheap "pot metal". I understand that a lot of that stuff is not weldable.

Are they cast parts? That's where pot metal is commonly used.

Yep definitely cast, light duty cheap stuff. What is "pot metal"? (I mean in terms of the periodic table)

Sounds like zinc when you try to weld it. Pot metal is just cheap garbage zinc/aluminum alloy.

Ahhh... zinc/alu that would explain everything, and it reflects what I'm seeing.

So JB weld or garbage? No chance to try to weld it? I guess I could try solder...

For pot metal castings that were not under stress or strain I have had some luck with old fashioned superglue and also the h20 activated gorilla glue. Just for knobs and the like. Not for any things that actually does work

Just saying

There is one welder guy in the area here that used to be able to sometimes successfully weld pot metal. No guarantees but he got a few things done for us. Had about a 75% success rate. That guy is a master welder, i believe known nationally through some trade groups. So it may be possible but you might need to be a genius to do it. Which many consider this guy to be.

Jakedaawg wrote:There is one welder guy in the area here that used to be able to sometimes successfully weld pot metal. No guarantees but he got a few things done for us. Had about a 75% success rate. That guy is a master welder, i believe known nationally through some trade groups. So it may be possible but you might need to be a genius to do it. Which many consider this guy to be.

I have done that metal before, absolutely sucks. Its a mixture of different types of metal, I believe it's Zamak.

https://en.wikipedia.org/wiki/Zamak

Garbage, Garbage, Garbage. Can be welded though, its similar to brass but droops really easy. I did it on a foot for an oven once.

BigD wrote:Ahhh... zinc/alu that would explain everything, and it reflects what I'm seeing.

So JB weld or garbage? No chance to try to weld it? I guess I could try solder...

You could try soldering it. Anything is better than JB weld or crazy glue. Or retro-fit another knob in it's place.

Could be sintered metal. More or less just powder and flakes pressed togeather into shape. Even if it was a good grade of metal there's so much air space between the grains it just desolves and shrinks under melting temps.

Definitely a zinc alloy but slightly magnetic?

It can be repaired with torch soldering using that aluminum repair rod which is a tin-zinc alloy. Melting point around 600 °F so watch out. Propane or MAPP equilavent.

Weld it like you would brass, the zinc evaporates first, nothing to be done about it. Just keep stepping on the pedal, don't let it get too hot, fire, stop, fire, stop, fire, stop. With some silica bronze you might just make it out alive.

ITs tricky stuff but it can be done.

Also know as Die Cast here in Australia

I've seen the stuff called many names - none of them good ! but on the bright side " HTS 2000 " or similar bonds to it very well - kinda like brazing / soldering though I'd say a well cleaned joint will have as much strength as the parent metal.

weldin mike 27 wrote:Also know as Die Cast here in Australia

Die cast is a process, not a material. I can GTAW die cast aluminum all day long without a hitch. But zinc, Zamak or other low temp cast metals are a problem due to hot short properties and high vapor pressures.

Muggyweld makes a brazing rod for pot metal.

Thanks a lot guys, yeah that tin brazing rod for aluminum sounds like it may work. I've just never seen anything like that and I've done brazing with sil-bronze, but I've never seen outgassing like this except maybe lighting up on aluminum with no argon on DC.

Keith_J wrote:

weldin mike 27 wrote:Also know as Die Cast here in Australia

Die cast is a process, not a material. I can GTAW die cast aluminum all day long without a hitch. But zinc, Zamak or other low temp cast metals are a problem due to hot short properties and high vapor pressures.

It's obviously more of a colloquialism here in AUS. as in "Thats a bit of die cast"....

And its a polite statement.
Unlike what most welders will call it.

While I have not used this product I have had great results with their silver solder on stain less steel

http://muggyweld.com/pot-metal-repair

Mark