Aluminum or Magnesium?

[Xray]

Hi all! This is my first post on the Miller forum.

I use my Econotig for general hobby welding, and I occasionally use it for my X-ray repair business. One problem that I recently encountered is I was trying to repair a broken metal bracket that holds a rear cover onto a Dental X-ray tube head. From the look and feel of the metal, I was certain that it was cast Aluminum, but I had a heck of a time trying to Tig weld it. The broken section of the bracket is only about 0.25 in wide by 0.125 in think, and about 3 inches long. The metal seems to be very brittle, as it breaks very easily when flexed even a small amount. When trying to Tig weld it, the metal just melts into a very rough looking blob, and will not accept Aluminum filler rod. After many frustrating attempts, I began to wonder if maybe the metal isn't Aluminum, and is rather Magnesium. So, could anyone please tell me how I could test the metal to determine if in fact it is Magnesium instead of Aluminum? BTW - I'm using pure Argon, with 1/16 inch Thoriated Tungsten.

Thanks!

[shorerider16]

Unless you are welding in a vacum chamber that has been purged, welding magnesium would cause it to burn, and boy does it ever burn. (I guess grade 9 science was good for something after all. )

[migman69]

Thoriated Tungsten

I believe you may want to consider some other kind of tungsten since i have heard this type is very harmful to your health without proper ventalation.

[KBar]

(I guess grade 9 science was good for something after all. )

Back in the 60's we used to play with the different metals in science class. Our teacher would sneak in the back room and pull out his flask on occassion, we didnt see him for 15 minutes so we would play with different things, mercury was fun and we almost burnt the lab up. Yes, science was fun

[Xray]

Unless you are welding in a vacum chamber that has been purged, welding magnesium would cause it to burn, and boy does it ever burn. (I guess grade 9 science was good for something after all. )

Yes, I recall from High School Chemistry class that Magnesium does burn, but it requires Oxygen to support the combustion. I don't believe it would burn when shielded by the Argon.

[Xray]

I believe you may want to consider some other kind of tungsten since i have heard this type is very harmful to your health without proper ventalation.

I believe you are referring to the fact that Thorium is slightly radioactive, which is very bad to breath into your lungs. I Tig weld with very good ventilation, even when using pure Tungsten. Any metallic vapors are bad to inhale, and some are much worse than others. The Miller site has lots of good articles about welding safty, which include plenty of warnings about smoke and fumes given off by the welding process.

[TS-Off-Road]

Unless you are welding in a vacum chamber that has been purged, welding magnesium would cause it to burn, and boy does it ever burn. (I guess grade 9 science was good for something after all. )

Magnesium welds fine. You need magnesium filler for it though. Don't leave any grindings or shavings laying around, those WILL burn!

[TS-Off-Road]

I believe you may want to consider some other kind of tungsten since i have heard this type is very harmful to your health without proper ventalation.

A lot of myths flying around here!

It's kinda like lead in paint - If your dumb enough to eat it.....

[Xray]

Back in the 60's we used to play with the different metals in science class. Our teacher would sneak in the back room and pull out his flask on occassion, we didnt see him for 15 minutes so we would play with different things, mercury was fun and we almost burnt the lab up. Yes, science was fun

What else is there besides welding and riding??? Hmmmm..... I can think of one thing, but I might get kicked off this forum if I mentioned it!

[Randy Forbes]

Magnesium welds fine. You need magnesium filler for it though. Don't leave any grindings or shavings laying around, those WILL burn!

I agree. I repaired three (3) vintage go kart magnesium wheels yesterday. I've also done BBS (BMW) & Ferrari wheels. The BBS was a joy to weld on, quite free of contaminates. Ferrari and old McCulloch wheels are more challenging to get a porous-free interface of old & new.

The filler rod is expensive (last purchase $92/Lb.) but a pound goes a long way! Trick is to find a supplier willing to sell less than 10 Lbs!

I saved all the shavings from turning a repair (lathe swarf) in a paper bag and threw it on a bonfire. VERY bright white, but quickly burnt itself out. Don't try that in your shop! So yes, keep the area clean from shavings and grinding dust.

Magnesium oxidizes very quickly, so any repairs need to be cleaned back to bare metal. I usually use a carbide "tree" in a die-grinder for this. It helps to direct the chips away from your clothing.

[Xray]

I appreciate everyone's comments, but I'm still waiting for an answer to my question of how to dertermine what type of metal I have. I suppose I could shave off a few splinters of metal with a knife, and then try to burn it with a propane torch. If it glows very brightly while burning, then it probably is magnesium. Does anyone know of another way to test metals in order to determine what they are? I know with various grades of steel you could determine a lot about their makeup with a spark test by grinding them and seeing the color, brightness, and types of sparks that fly off. That basically shows how much carbon is in the steel. But what about testing Aluminum? Is there a simple test that can help you determine the type of Aluminum that you are about to weld?

[griff01]

A lot of myths flying around here!

It's kinda like lead in paint - If your dumb enough to eat it.....

The thoriated tungsten being radioactive is not a myth. If you want to use it by all means, go ahead. But don't mislead others.

Magnesium welds ok. But as with aluminum, you need to know the base metal grade to be sure to get the right filler. Anything else is a guess.

Griff

[Xray]

The thoriated tungsten being radioactive is not a myth. If you want to use it by all means, go ahead. But don't mislead others.

Griff

I don't believe that Ts-Off-Road was trying to mislead anyone. I believe that he was just making a point that if a person is careless with ANYTHING (including thoriated tungsten) then you can get injured, sick, or die from it.

[jamscal]

You may be able to weigh the material vs. what it displaces in water to find the...I forget the terms. specific gravity? I don't know. Anywho, compare this number to the periodic table of elements and get your answer.

Magnesium seems to oxidize to a duller/darker gray than aluminum.

You might also try to burn some shavings.

You can also try to form a puddle with the tig torch and no filler, just to make sure you can do it.

Still popping and going crazy? It might be a zinc casting.

-James

Re: Thoriated: I try to be pretty safe, but every shop I've worked at has 2% thoriated.

-I've never seen a specific warning about radioactivity on the package, and only know that it is mildly radioactive via the internet. (I'm sure they have the standard: "This causes cancer in California" warning though)

-I'll regrind my tungstens a few times a day long before I work in a paint shop.

-I was looking at the warnings on a box of mig wire the other day and was pretty scared by that too.

-The Earth is mildy radioactive.

[Showdog75]

Seems like I read that vinegar will start to bubble up on magnesium .