Welding Cast blend of Magnesium/Aluminum

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Is this doable by any means? I had a customer drop off a bell housing saying it was aluminum, but after trying to tack it and it cracking instantly after that, I figured it might not be. I call the manufacturer up and they told me its a blend of Magnesium and Aluminum. Having never tried welding that, I asked the manufacturers if it could be welded in anyway, they said no. But Just wanted to make sure that it really isn't doable, and they're just not trying to get the guy to buy another one.
Reply:Hello dj55b, if it is in fact a combination of aluminum and magnesium you "may" be able to weld it providing the percentages of each element are skewed, meaning if it has a definite higher percentage of magnesium it may be weldable with a magnesium filler, if it is mostly made up of aluminum, the aluminum filler might work if you go with a 5356 filler. If you feel that you can invest some time in a trial and error approach I would say go for it. You may already know that if you try to weld magnesium with an aluminum filler that the "weld" will make a pinging sound and literally fall out after you have completed it and vice-versa for the other way around. If you are trying to get a feel for whether a particular material is magnesium, using silver nitrate will cause the material to turn black if it is magnesium and it will stay clear if it is aluminum. Just a few $.0's worth for your consideration. Good luck and best regards, Allanaevald
Reply:Thanks for the info. Ya I learned that the hard way, and yes it does ping and the aluminum does fall out of it and crack instantly. I was looking online and there seems to be a filler that might do the job (ER AZ92A) but at the cost of 230$ per KG. If I forward that charge, plus my labor time to the guy that wanted this done, he could probably almost buy another one. But I can't even guarantee that this filler will work.
Reply:I thought that might be the case. It's funny how you will often have people show up and make a statement like: " it only needs just a little bit of weld, most likely a five minute job". Unfortunately, we generally know better. Best regards, Allanaevald
Reply:The alloy magnalium is used extensively in pyrotechnics.  Usually it is a 50/50 blend.  It has replaced magnesium due to it's decomposition with water.