[WStone]

I've an interesting project.
Magnesium chainsaw crankcase with a hole through the front of it.
Was able to get most of it patched up with weld(AZ92A filler), but have a pinhole on one side of the repair.
The hole is in the front of a cast magnesium bar and chain oil tank, and I can only take so much material off to try and get to clean metal before it's not salvageable. I think I can get one more try to run a bead over the pinhole with one more filler rod (spendy stuff at $110 a lb, luckily my shop sells by the stick).
Anyhow, barring that, I'm not having much like finding info on brazing magnesium. I found a white paper on a few processes, but that didn't help with practical info for actually working with it.
I'm hoping that it might be possible to TIG braze it with Silicon or aluminum bronze? It's not really a structural concern, mostly just need the oil tank to seal up.
Any ideas?
Thanks in advance.

[Superiorwelding]

JB Weld
-Jonathan

[Otto Nobedder]

Jokes aside, I'd consider a simpler process... Solder the last hole up.

A simple tin/lead plumbing solder will do.

Steve S

[Superiorwelding]

Jokes aside, I'd consider a simpler process... Solder the last hole up.

A simple tin/lead plumbing solder will do.

Steve S

I agree, Silver solder should work fine. I have never welded on brazed magnesium so I have no direct experience. I do know where I can get some filler material and would like to give it a go one day.
I was half serious about the JB Weld. I have seen some wonderful things done with that product.
-Jonathan

[WStone]

Many thanks, was thinking of trying silver solder, but unsure of the metallurgy.
Good call on the JB weld, but the previous owner had tried to patch the hole with JB weld which is why it had been leaking. push comes to shove I can try lining the inside of the weld in the oil tank with some JB weld or other epoxy after a thorough cleaning with some type of solvent. I'll try soldering first, as I'd have more faith in that.
Having mostly patched the hole, I will say that the oil soaked magnesium casting is far from the easiest thing I've welded. Had a heck of a time getting the base metal to puddle before I could get a bead going. Once I had a bead around the edges I was able to stack on it no problem, just had a bit of porosity on one side of it. Functional repair is the name of the game on this one.
Thanks
Will

[Antorcha]

JB weld sucks. Rough it up a little and cut a bandaid out of something beer can thick( like a beer can )
Rough that up a little too, clean it all and use some 3M two part epoxy to apply the "band-aid". Put the letters in or you'll look like a dumb rucking fedneck.
If you can't get 3M look for Devcon 2500.