Mystery Metal

[tornitore45]

Sorting through inherited junk i run into a chunk of very light metal

The dark matte gray scale (Oxide ?) scratches to a shiny bright similar to Aluminum.
The specific gravity determined with my "lab grade" kitchen scale turns out to be 1.77

I just looked up Magnesium, in pure form has density = 1.738

Any idea what it is? Do Magnesium alloy burst into flame when machining?

[whateg0]

You can do the vinegar test to help confirm it's magnesium. Magnesium doesn't automatically burst into flames but when it does, it's not cool. I've seen YouTube videos of guys welding it so I'm not sure what I've had to do to ignite it.

[Russ Hanscom]

Shavings of magnesium are very flammable, the chunks not so much. Story about a machinist who could not be bothered to remove the shavings from his lathe, had a real meltdown.

Consider your handy little fire starting tool, scrape off a few shavings, put some sparks into the shavings.....

[Harold_V]

The specific gravity of prepared (alloyed) magnesium will vary from the pure element. The description provided indicates to me that it is, indeed, magnesium. Unlike most aluminum alloys, it's "crunchy" when machined.

You haven't lived until you've witnessed a magnesium fire. The dazzling white flame is enhanced by the addition of water, very much like tossing gasoline on a fire. Been there, done that, and have the singed arm hair to prove it.

H

[tornitore45]

You haven't lived until you've witnessed a magnesium fire.

When I was about 7 my brother and I went to the Luna Park. My brother tried the Photo-shooting where if you hit the bull's eye a photo is taken instantly. Looks cool staring right at the barrel. Believe it or not they still had Magnesium Flash back in '52.

[Mr Ron]

Thermite is an iron powder which reacts when potassium permaganate and a piece of magnesium ribbon is activated with glycerine. I've done this to weld some steel together; very hot. Don't try it at home.

[John Hasler]

The specific gravity of prepared (alloyed) magnesium will vary from the pure element. The description provided indicates to me that it is, indeed, magnesium. Unlike most aluminum alloys, it's "crunchy" when machined.

You haven't lived until you've witnessed a magnesium fire. The dazzling white flame is enhanced by the addition of water, very much like tossing gasoline on a fire. Been there, done that, and have the singed arm hair to prove it.

H

I once watched 500 lb of magnesium burn from about 1/4 mile away. Sunglasses were required.

Several hundred pounds of thermite were also involved.

[John Hasler]

Thermite is an iron powder which reacts when potassium permaganate and a piece of magnesium ribbon is activated with glycerine. I've done this to weld some steel together; very hot. Don't try it at home.

Thermite is usually a mixture of iron oxide and aluminum. https://en.wikipedia.org/wiki/Thermite

[jcbrock]

I was working at a facility manufacturing a product from an aluminum/magnesium alloy. One of the processes was a turning operation that used kerosene as a cutting fluid, with vacuum evacuation of the chips to a 20 yard dumpster outside. All well and good until a guy welding on the roof let a few sparks float down to the dumpster. Things then got really ugly when the water-based fire suppression system above the dumpster activated. I'm not sure how that series of errors came to be, Murphy's Law I guess.

[Rich_Carlstedt]

......................The specific gravity determined with my "lab grade" kitchen scale turns out to be 1.77
I just looked up Magnesium, in pure form has density = 1.738 Do Magnesium alloy burst into flame when machining?

Sounds like magnesium
Usually you only hear of the dramatic "failures"
Yes, it can be machined ...and is every day
Just don't let piles of chips build up, particularly Hot piles !
Also have a bucket/box of sand nearby - The sand will suffocate the fire if one starts
Rich

[Mr Ron]

Thermite is an iron powder which reacts when potassium permaganate and a piece of magnesium ribbon is activated with glycerine. I've done this to weld some steel together; very hot. Don't try it at home.

Thermite is usually a mixture of iron oxide and aluminum. https://en.wikipedia.org/wiki/Thermite

I stand corrected. It was 70 years ago that I messed with thermite.

[chief]

Just to ad my 2 cents worth, Harold's post about the water brought back a memory. Long ago in a galaxy not too far away, I was in an aircraft fire fighting class in the navy. As a demo of what not to do, they had an A3 aircraft magnesium main mount wheel in a fire pit and hit it with a fire hose. It pretty much exploded like a good sized bomb.

Terry