Do aliens make this stuff?

Some time ago I bought a job lot of metal stock which came from the estate of one of the brethren. Amongst it is something that I am unable to identify. The piece is approx. 20mm square and 200mm long and appears to have been cut from 20mm thick sheet. Judging by the thick almost black corrosion it is either pretty ancient or has lived for a long time under water.

Today, curiosity got the better of me so I hacksawed a wafer from one end. It sawed like aluminium, it looked like aluminium but it's not aluminium because (and this is a rough guess) it feels like only half the weight of aluminium.

The strangest thing about it though is that I had to put a face mask on as the hack sawing filled the air with a fine silvery dust.

I have never worked with titanium so maybe that is what this stuff is but might my poor old deceased model maker have recovered this weird stuff from the wreck of a UFO?

What do you reckon?

Rik

Magnesium?

Roy.

Is it definately metal - did it get a lot hotter than when you saw steel?

Titanium is heavier than aluminium whereas magnesium is lighter. Why do you not measure the density?

Mike

Or ignite the swarf.........

UPDATE - Just been up the shed and shaved of a bit with a Stanley knife and gave it a blast with my cooks blow torch. Instant gratification - a spectacular white glare as the stuff burnt. Magnesium it IS!

I have another piece 50mm x 20mm x 300 as well so I will look forward to doing something interesting with it at some time. (Without burning it of course).

Good suggestion there Jonathan!

Rik

If you are into model airplane engines it would make a good crankcase for one. Arden glow plug engines had magnesium crankcases

Clive

Edited By Clive Hartland on 23/02/2014 20:27:09

G'day.

Be careful of the swarf when you machine the stuff and how you dispose it.

As you already said 'spectacular white glare'.

Maybe a bucket of sand could be handy or a CO² fire extinguisher.

I am sure that the more learned members of this forum can point you in the right direction.

And as Clive said, it does make lovely crankcases, my early Mills engines use this material although they had some (chromate?) treatment to make them last. Whatever it was, they still look good after 65 years.

Regards * Danny M *

"Maybe a bucket of sand could be handy or a CO² fire extinguisher."

Magnesium on a Mission would just laugh them off. As I mentioned in another thread I am melting Aluminium, I check very carefully for magnesium because once lit in the furnace there is no putting it out - The Chernobyl Effect.

Simple test is a couple drops of vinegar, if there is a reaction it is Magnesium.

You seem to have some biggish chunks, be respectful of them or they will bite you.

graham.

Edited By Oompa Lumpa on 23/02/2014 21:48:36

I am in a similar position, having a stash of mag. alloy, that is. Because of the difficulty of dealing with a magnesium fire I decided a long time ago not to use it, and just let it corrode quietly away.

cheers

Bill

When I first started work, I was a spectrographer and was asked to identify a lump of white very light metal, luckily I shaved a few slivers off it and arced them - magnesium!!

So glad I didn't just run an arc on it!! What a firework display that would have made!

Peter

Just saw this,....magnesium was used by the Germans for their infamous firebombs during the 'Blitz'. The magnesium casing simply held the fins and initiator...the fiercely burning casing did the damage! The only way (difficult) to extinguish is to smother with a substantial helping of sand, the problem being the surface that the magnesium is burning upon often defeats the sand application. In the years just after WWII firebomb casings were often turned down in the lathe to make magnesium dust for homemade fireworks. I used ot have a neighbour who was asked to do this by his headmaster to provide fireworks for the VE celebration in 1945!!

We had one come down the bungalow chimney and the ARP scooped it up and put it outside. He had goggles with little crosses to see through and long handled scoop and a rake. Damage was minimal as it was on the cement hearth.

From then on all the kids collected the ones that did not go off as they fell on soft farm land. They stuck out like teeth under the trees. The older boys unscrewed the end and poured out the magnesium powder and there was quite a pile of it. A trail was laid and it was set off and the biggest FLASH ever happened and everything in the garden was covered in white powder residue. Bullets were the next best thing as we were always finding them in the gutters, also shrapnel. Was I really just 6 or 7 then ?

Clive

My Dad was a kid living in Birmingham in WW2

It surprised me when he told me WW2 was a great time to be a child.

The adults were far too busy to bother kids with their petty rules and regulations

Someone did quite a good film about it

Hope and Glory

Edited By Ady1 on 02/03/2014 11:19:58

I know it is fun to get excited about hazards, but as engineers (or hobbyists) we shouldn't replace science with sensation. Rik probably has a magnesium alloy and these have been extensively used in high performance engines and aircraft, where weight is a premium, without undue hazard for many years.

Magnesium powder is a very different hazard from solid magnesium alloy. When magnesium is combusting it will react with oxygen, CO2, water and even nitrogen, which is why only a dry sand will extinguish it.

A thin piece shaved off an alloy can be ignited in a hot flame because you have taken it beyond its melting point, but it is difficult to ignite a solid lump because even if one corner is molten the larger portion will take the heat from any combustion. It can be cut with machine tools but grinding is not sensible as the fine dust is the fire hazard. Welding and casting are for experts, but I think it is TIG welded with a normal argon gas shield.

Lots of materials go bang if you make them fine enough or hot enough.

Norm.

Got six 3" diameter bars of the stuff, about 3 foot long.

Never found a use for it other than getting some nice fine wide turning and scrunching these up into bits and throwing them over the shoulder of someone when they are welding.

Awesome reaction and the smell of $h*t is over powering

It may sound silly but Magnesium can make good castings. My uncle was a metallurgist who wrote a book on casting the stuff after the War. It would be interesting to attempt to make a casting. I believe Sulphur is used to protect the molten metal from being attacked by air. Again I believe sand was used to put out fires when it was being machined. This would have led to very thorough cleaning of the machine being used.

Parts made from Magnesium have poor fatigue strength and the metal deteriorates with age.

JA

"It would be interesting to attempt to make a casting."

 ------ hope you are not looking at me!

"Again I believe sand was used to put out fires when it was being machined. This would have led to very thorough cleaning of the machine being used"

......cor, I bet !

"Parts made from Magnesium have poor fatigue strength and the metal deteriorates with age."

Then I am become "Magnesium Man" !

Rik

PS, JA, I jest - no offence.

Edited By Rik Shaw on 02/03/2014 18:04:56