How do you identify magnesium?

Have a question or want to show off your project? Post it! No Registration Necessary.  Now with pictures!

Threaded View
Is there an easy way to tell the difference between aluminum and
magnesium? I TIG weld lots of aluminum castings, and have been given a
few magnesium castings as well. In those situations, I was told
beforehand that the casting were magnesium, but lots of people bring
me castings without knowing what they are. Thanks!

Re: How do you identify magnesium?
Have welded Magnesium and it requires a special Mag. rod , I used to test an
unknown material , be it Alum. Mag or whatever with a very basic idea ,
instead of spending an hour grinding and fitting and then find out my
project wasn't compatible for weld , I would clean a small spot and build up
a small post , perhaps 1/4 in. dia. and 1/4 in. high , clamp onto the post
with a vise grip and put some torque load on the post or pillar and see how
it broke , if it takes a lot of twist and finally pulls some of the base
metal as it breaks , I would be satisfied to go ahead and weld , if the
pillar falls off or snaps very easy , you can stop and try something else .
Good Luck , Phil L.
Quoted text here. Click to load it



Re: How do you identify magnesium?

Quoted text here. Click to load it
Or,using a clean file or sharp knife, file or scrape a bit off the
suspected material and try to light it. Magnesium burns :-)

Bruce-in-Bangkok
(correct email address for reply)

Re: How do you identify magnesium?

Quoted text here. Click to load it

If you have room to be a little destructive, you can drill it and/or scrape
it a bit with a sharp knife.

What little mag I have worked with seems to be a bit more silver in color,
and have dusty or flakey cuttings or chips.

Aluminum will appear more white in color by comparison, and the chips or
shavings will appear more soft or gummy.

Mag always seems to "appear" harder than aluminum, sometimes even causing a
drill bit to squeal as it cuts.

If you get a "known" piece of both materials together and experiment with
drilling, filing and scraping them - I think you get a feel for it.

If you can afford enough damage to grind test, they grind very differently
as well.




Re: How do you identify magnesium?
matthew wrote:
Quoted text here. Click to load it

Get it really hot and drop it into a bucket of water.  If it burns your
shop down it was magnesium.

--

Tim Wescott
Wescott Design Services
We've slightly trimmed the long signature. Click to see the full one.
Re: How do you identify magnesium?
Thanks for the responses!

Site Timeline