I need magnesium welded or a case half

[Huskybill]

I setup the Hobart 300 cyber wave TIG and try it on scrap first that’s a most. Apply too much heat we get distortion and warpage. A little pre heat gets that last bit of oil that’s embedded in the metal.

Tip
Don’t forget to center the crank when assembled, put the rod pin at bdc and using a cold chisel in the pork chops lightly will remove any stress on the crank. If the crank feels tight. With pressed in bearings. The crank can sometimes angle in on the outer porkchops.

 

[Ted Jenkins]

When I was working I took on the welding and fabrication as well as the lead engineering tech, r& d development . In my welding department I took on every welding job that most thought was impossible. Just to learn more. Welding magnesium was one of my favorites. I tig welded all magnesium cases. We had a certified welder before me. He was certified in all types of welding and cutting even under water. He knew he was leaving the job but before he started giving me crash courses on all the welding processes. While I was going to school for welding. You can be as good as you want to be just apply yourself and stay motivated.

Some thing I did not put too much effort in was putting some mag stuff in to my enclosed welding container. I built a box to weld some titanium in which does work, but compared to what I am not sure. I took some fairly heavy sheet metal and made a enclosed box with a lexan cover to see what I am doing. My hands and arms go through two openings in the front part of the box with some rubber to help seal around my hands then I run argon for a minute before starting to weld. Is this what needs to be done before starting to heat up magnesium in order to weld. Thanks

 

[srcarr52]

For one thing crankcase halves are usually finish-machined together so the match perfectly,using a half from one motor to another may mean bad crank alignment,cyl. surface uneven etc. They are always recommended to be replaced as a matching pair,but some people get away with mis-matched halves.
As for welding magnesium ,I have not seen anyone able to do it well without risking destroying the part in modern times with modern equipment,if any modern welder brags he can first bring him an old piece of magnesium to weld,see if he succeeds before you cook your saw part. But in the 80's in our saw shop we welded broken or cracked magnesium all the time successfully,but we used oxy-acetalene,magnesium rod and a jar of special flux. It took some practice,but once you got it flowing it is almost like brazing(brass) with acetylene. The oldtimer who taught me just had me bust some old magnesium parts,then weld them together for practice.
I suppose no one has acetylene welding skills anymore,I also did all the aluminum welding on saws (mostly handlebars) very well with acetylene also.

I've mixed and match larger 2 and 3 series Husqvarna case halfs with no issues. Their machining tolerances seem to be much tighter than Stihls. I've had to use unmatched cases on 066's before and the deck height between the two was 0.008" off but the crank bores where not an issue.

As far as magnesium welding, TIG is the best modern day process. Proper cleaning makes a big difference but even then the base material is not very pure and you'll still end up with a few pin holes. Old Homelite parts are actually the cleanest base material I've ever welded, Stihl 0 series or Mac are the worst. Here are a few different parts I've welded.
Stihl 066 spike mounts, Husqvarna 3120 bar pad, Homelite not sure of the model.

 

[Ted Jenkins]

On my last attempt at welding a magnesium alloy with a TIG welder proved to be some what of a failure. The parent metal with in a .5'' to 1'' looked like a pock filled series of craters. The welds looked beautiful and were strong, But the welds broke away from the parent metal easily. Using a large amount of shielding gas and my heli arc proved to be the best. Thanks

 

[srcarr52]

On my last attempt at welding a magnesium alloy with a TIG welder proved to be some what of a failure. The parent metal with in a .5'' to 1'' looked like a pock filled series of craters. The welds looked beautiful and were strong, But the welds broke away from the parent metal easily. Using a large amount of shielding gas and my heli arc proved to be the best. Thanks

Yes, you really need to use a lot of argon with mag and the least amount of heat necessary.

 

[Yotaismygame]

Shaun do you take in damaged cases? I've thrown away some that probably could have been repaired. Thy're no use to me and i'd gladly send them your way if you paid shipping.

 

[srcarr52]

Shaun do you take in damaged cases? I've thrown away some that probably could have been repaired. Thy're no use to me and i'd gladly send them your way if you paid shipping.

Certainly, I run Shaun's no kill case shelter. LOL!