Magnesium?

[Protraxrptr17]

Is it possible to weld magnesium without much trouble? I have an engine that has a magnesium clutch cover. I would like to make my own quick access cover for it if it's not a huge task. I would have to machine off part of the existing cover, make my own flange and quick change cover and then weld the flange to the old cover. I guess I would have to find a chunk of magnesium to make that stuff out of. Is there a chance that aluminum and magnesium can be welded together? I can buy a billet aluminum cover with the quick change already installed, but I want to make my own if I can. I've attached a picture of an engine like mine so maybe you can see what I'm talking about. The round part that says KTM racing is what I'm machining off. I want to be able to take that part on and off without taking off the whole cover so I can replace the clutch plates underneath. Understand?

[dyn88]

why dont you just machine out a round area the size you need and drill tap and helicoil a bolt circle? Make an aluminum cover with a common oring size and bolt that on.

[Protraxrptr17]

I thought about that but I don't think I have enough material to do that. I don't have the engine in my hands just yet to measure it. I bought this engine yesterday and it should be here next week sometime.

[Bendaman]

If you plan to machine that cover off, be careful what you do with the filings
left behind, should those catch fire there is not way to extinguish the
filings. Water or fire extinquishers will not put out a magnesium fire. I
know someone who works with magnesium, its tricky stuff to work with.
Use caution: Good luck with your project.

[aametalmaster]

I am not sure about welding alum to mag, but you can weld mag with a tig real nice...Bob

[Mike W]

Where would one shop for magnesium ?

[aphexafx]

If you don't mind having it shipped to you, and paying for it to be shipped to you, there are a bunch of suppliers listed here:

Magnesium Suppliers

Perhaps one of them is close to you (whoever needs it).

[eric75]

I know it can be done, but if it is so prone to catch fire, how can you weld it?

There must be some special procedures to keep your part from catching fire. Like removing any chips, shavings and burrs?
What about gas, higher flow rate? different mix? purge tank?
Bucket of sand to put out fires?

I had a professor once who always made jokes about getting his students to try welding magnesium, as if it would explode of something. Is this a big safety hazard or just an occasional annoyance?

[joebass]

I think that only the dust and smaller chips and shavings are what is flamable. It should be TIG welded using AC.

[wrench3047]

It's a matter of surface area. filings and dust from machining will ignite with a single spark, but a (chunk) piece can be welded, heated with a torch so on. It burns like phosphorus white flame.

[Protraxrptr17]

Thanks for the help fellers, but how do you do it? Such as machine setup, material prep, type of filler, and so on. I remember now about it being flammable when shaved. I saw a survival firestarter once that had a chunk of magnesium and some flint. It claimed it would burn even when wet.

[wrench3047]

Sorry never even seen it done.

[Blown S-10]

i don't know. but i would think the shielding gas would prevent it from bursting into flames.

[Paul Seaman]

I am not sure about settings but I do know that it requires a really long post flow time to prevent and ember from igniting the manganese. I've seen it done but not rescently and am a bit foggy about setting up for such. As I remember he used a shielding gas shoebox and Argon. AC welding current and pure tungsten were used but that is all I remember.

Hope this helps some,

[stinkinlincoln]

My book "Welding: Principles and Applications" says:The joining of magnesium alloys is possible without a fire hazard because the melting point of magnesium is 858 degrees F to 1202 degrees F below its boiling point where it may start to burn. The book also recommends ER AZ61A for joining wrought magnesium. ER AZ92A is recommended for joining cast alloys, becuase of higher resistance to cracking. I assume this case is cast. If magnesium castings are anything like aluminum castings (full of porosity), welding it could range from miserable to virtually impossible for that fact alone. All the porosity in the casting near the weld will cook out and ruin the weld, it might need to be cleaned out and rewelded several times to get a sound weld. However, I don't know maybe magnesium castings don't have so much porosity.

The "GasTungsten Arc Welding Handbook" says magnesium tends to distort more than aluminum (ooooh goody). It also says magnesium requires approximately 2/3 the amount of heat that an equal thickness of aluminum requires. Apparently magnesium is very prone to cracking (ramp current down slowly and fill craters completely). Also, joints must be very clean, probably use a brand new stainless brush followed by acetone immediately prior to welding. Cleaning the filler rod is also a must, says the book. Preheat to 300 F is required to avoid cracking. Post heat of 500 F for 60 min is also required.

AC current is mostly reccomended in the books, of course you don't want to do that with a dynasty. Mostly, use procedures very similar to aluminum. The combination of preheat and tendency to crack and the fact that it is a fairly thin casting all mean pretty low amperage. Argon should work fine.

I have never welded magnesium. But I do have lots of fab experience and plenty of tig arc time. Frankly, I probably wouldn't even attempt it.

Any good supplier of magnesium or filler will be able to give practical experience advice. Andy or Hawk will probably chime in some time with advice. If it can be done one of them has likely done it.

Oh yeah, I couldn't find any info about joining magnesium to dissimilar metals. Probably impossible.

If you decide to do this or weld any other magnesium for that matter, please post your experiences. I'd like to hear. Good Luck.