How to repair a Magnesium Saw Housing

by Zach Johnson

I am a Bricklayer/Foreman and Certified Welder. My company as well as every other masonry company and many others have had the same problem.

We use gas powered chop saws which have a magnesium piston housing. Our quickie saws seem to have a major flaw in the design, the piston housing and the mounts for the feet and the bar that holds the blade are all one piece.

If you break the saw in any of these places then you have to replace the whole housing, mounts and bar, its about an hour and a half process and its a very expensive part.

Thanks to the Welding Advisers site I was able to find the right welding process and some tips and tricks that helped me learn to weld magnesium.

All I had to do was pull off all the plastic covers that were in the way, take the handle off the saw and wire wheel clean the broken parts, then just weld them back together.

Clean, clean, clean! Back side, front side, everything needs to be clean at least a 1/2 in. either side of the fracture.

So I Tig welded the magnesium housings and used a 2% thoriated tungsten electrode with pure argon in AC, and AZ91 filler rod.

After welding a few of them, I learned that you absolutely can NOT get your base metals too clean. I used a stainless wire wheel to prepare the parts and a stainless wire brush in between welds.

I can now repair our gas powered chop saws which have a magnesium piston housing.

I just wanted to say thanks for all your help, all of the information you provided about welding Magnesium has helped me in a big way.

Thanks again,

Zach Johnson

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