[MarkL]

I dropped my circular saw and broke the blade guard, which is magnesium. I'm pretty good with steel and aluminum, but never welded magnesium. What filler would I use, any tips on settings? Hopefully I can use argon. I've done some brazing, would that be a better option? Here's some photos:
https://photos.app.goo.gl/Qu2Mga4nSXNBiYAD8

[LtBadd]

Mark, magnesium is welded on AC and with argon, and you'll need the correct filler, google for specifics

HERE is an article Jody wrote on welding this alloy

How do you know the guard is magnesium?

[MarkL]

Thanks for article, I'll look at that. The manufacturer bragged about the saw guard and housing being magnesium because it's light weight. It's no longer made or I'd order a part. I have right and left hand versions of the same framing saw, so I'd like to keep it running if possible.

[MarkL]

Wow, the filler is crazy expensive. I can buy a used saw off ebay for less than the smallest amount of filler I can find. I'll just get a used saw in lousy condition and cannibalize it for the part.

[LtBadd]

Most of my career I've TIG welded, but never came across magnesium, what was the cost for how much?

[MarkL]

Most of my career I've TIG welded, but never came across magnesium, what was the cost for how much?

Local shop has AZ101 for $90/lb. I found smaller quantity of AZ61 on ebay, $35 for 14 rods, not sure what the weight is. I probably need 1 piece so I'll give the rest to the welding program at local community college. It's good for the kids to practice with and they'll never be able to afford it.

[MarkL]

Most of my career I've TIG welded, but never came across magnesium, what was the cost for how much?

Local shop has AZ101 for $90/lb. I found smaller quantity of AZ61 on ebay, $35 for 14 rods, not sure what the weight is. I probably need 1 piece so I'll give the rest to the welding program at local community college. It's good for the kids to practice with and they'll never be able to afford it.

[noddybrian]

I'm doubtful it's magnesium - likely just an alloy with some in it - if it actually is nearly all magnesium them from my limited experience it's not worth trying to conventional weld it - last time I tried to ( part was unknown but not expected to be magnesium ) it caught fire close to the weld & was not much good afterwards ! - I think you may well need to do it in a purge chamber to be safe - if it's just an alloy with some in like many motorcycle casings then regular filler like 5356 will work - but on a smallish repair such as this I'd use a low temperature repair braze like HTS2000 - I've used it many times & it always works - depending on the shape of repair or if anything is missing you may need to form a backing mold around the repair to contain it till solid as the stuff runs like water - you can buy small quantities of it & it's not overly expensive for small jobs - bonus is you only need a heat source to use it.

[pgk]

A drop or two of vinegar on it, if it's magnesium it will react with aluminum it won't.

[hey_allen]

It's no longer made or I'd order a part.

Have you checked on eReplacementParts to see if they have a spare guard for your saw?
I've been surprised at times, just how many parts area available for some tools.