Repairing a broken magnesium mower deck

Joe Gandalf · 2013-06-02T18:09:16+00:00

My wife loves her old Lawn Boy push mower; it's very lightweight (esp. since I removed all the Rube Goldberg self-propelled mechanism) and easy to start - still! However, the magnesium deck has developed a crack that runs across the front of the discharge chute. I was going to bolt a metal plate across the crack as a repair, but it would be a really sloppy patch. The more I look at it, the more I want to weld it, but I know what Mg does when it gets hot enough to burn! Is there a way to do a decent join without destroying the mower? I only have a Lincoln tombstone AC welder, a cheapo HF DC Tig, and O/A gas setup. I also still have some of those "miracle" repair sticks that used to be touted at flea markets ("fix any Al device with just a propane torch - developed by NASA").

Jun 02, 2013 26 Replies

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Larry Jaques 13 years ago

OK. Works for me...I guess.

Bueno, Bwana.

4hrs/week is a lot of time. Now that I've removed my entire front lawn and am using a rider, mowing takes me only 35-40 minutes a week.

I _wouldn't_ call it a hobby, so I'd object.

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Stanley Schaefer 13 years ago

EPA says 2-cycle=bad ju-ju. So no more new ones. The one Briggs book talks about getting cat converters stuffed into 4-cycle mowers, they're ready with golfball-sized ones.

If it were mine, I'd drill the end of the crack, polish it up and JB Weld a piece underneath.

Stan

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John B. 13 years ago

We used to TIG magnesium quite regularly when I was in the A.F.

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Jon Elson 13 years ago

Yes, and you'd want to set up a back-side shield-gas flood system, too. Maybe a separate shield gas nozzle for the front side, too, and follow along behind the welding torch.

Jon

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Lloyd E. Sponenburgh 13 years ago

Jon Elson fired this volley in news:ttmdnc7wAMVCdjHMnZ2dnUVZ snipped-for-privacy@giganews.com:

Jon, all that's been discussed before in this thread.

Both sides of the work must be shielded until the Mg is well below yellow heat, and that will involve either cabinet welding, or several nozzles.

LLoyd

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Kristian Ukkonen 13 years ago

How about soldering it?

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or use the "miracle sticks" you already have, if they are similar.

If you really want spare one, check ebay..

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Michael A. Terrell 13 years ago

Is there a local Freecycle group? Ask for one, if there is. The same with Craig's list or any free local ads. Hell, even Ebay has got into local ads. Someone may have one in a shed, or garage and they don't bother to list it, thinking no one wants it.

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