Aluminum or Magnesium?

[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 .

[griff01]

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.

Point taken.

Griff

[Burnt hands]

Xray,

You have picked a good quick method to test for magnesium with the shavings test. The camping stores have magnesium fire starters for just this use.

This should separate magnesium from alum.

I don't know of a valid method of determining the exact alloy type except thru the use of a Niton xray gun. This is very expensive equipment and I have nobody near me who has one.

I can offer this: if you determine your alloy is magnesium, I have a 3/8" thick plate of mg AZ31B. I will slice a piece off for you to try to tig weld if this helps.

If your piece is alum, it may be easier to find the proper tig alloy.
I defer to others on this forum for their expertise.

good luck

[Bodybagger]

Here's a simple test based on the stochiometric reaction of these metals with HCl.

You'll need an acurate balance capable of measuring to the nearest .01 grams or so...

Cut a sample of at least 1/10th of a gram of your unknown metal and weigh it accurately. Cut a sample of at least 1/10th gram sample of known aluminum. Place each in a separate nonmetallic container with about 50 ml of distilled water.

Using commercial 20 degree baume Muriatic Acid (which is 10.17 molar hydrochloric acid), and using a small syringe or other accurate volumetric measuring device, add precisely 1 ml of the acid to each container and stir, giving it time to digest the sample.

When the bubbles have stopped (perhaps 5 minutes later), remove the partially digested samples.

This amount of acid will digest 0.124 grams of magnesium but will only digest 0.091 grams of aluminum. If they weigh the same after the reaction, they are aluminum. If the unknown is much lighter than the known aluminum sample (or completely gone), it is likely magnesium.

[Randy Forbes]

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

Yes, this works.

Put a few shavings of each in separate drops of vineager; the aluminum will do nothing, and the magnesium will react.

[Blackbird455]

You could do all this stuff involving experimentation with chemicals left over from your meth lab.........or.........

You could go to a recycler, and have them shoot it with a spectrometer.

In the scheme of things, it is a non destructive test.

I believe that it is a micro diameter laser that vaporizes a few surface particles , and then sniffs the particles out.

I do know that SOME laser spectrometers can even tell you the EXACT alloy , not just the name of the metal.

10% rule guys, try to be 10% smarter than the metal you are working with.