Mg

[budullewraagh]

soz for the simplicity of this post, but is it true that the blades of pencil sharpeners are made of 90% (give or take a few percent) magnesium? note: i'm speaking of those really cheap plastic and blade pencil sharpeners.

[Pleiades]

The rectangular blades? I’d say no, I’ve seen them rust. Maybe if the sharpener has a metal body….. that could be magnesium. If you look inside an electric pencil sharpener you will find a metal cylinder with spiral grooves on it that does the cutting of the pencil, I suspect this would be the magnesium part. I’ve not seen this cylinder rust, but other than that, I have no idea.

[LucidDreamer]

I opened mine up and it says stainless steel. Its one of those cheapies your talking about. Don't know about the other brands.

[budullewraagh]

that's unfortunate. i heard that they are over 90% Mg from another enthused chemist. what a shame.

[budullewraagh]

scratch that; it's not the blades, rather it's the casings. a picture:

if that didnt show up,

http://www.quiltcandy.com/media/noscps_lg.jpg

[YT2095]

the casing in the old pencil sharpeners (NOT the blades!) are indeed what you say, as are the old HDD chassis, you`ve been told quite correctly

[raivo]

Can anyone tell what is easyest way to know of some piece of metall that it is mostly Mg and not just Al?

[pulkit]

Al does not easily dissolve in cold concentrated acids such as sulphuric and nitric because of an oxide coating.......Mg will react with nitric acid in a jify....in fact even with extremely low concentrations

[budullewraagh]

old HDD chassis

what is/are that/those?

 

Can anyone tell what is easyest way to know of some piece of metall that it is mostly Mg and not just Al?

read above; the Mg is over 90%.

[Pleiades]

I figured it was the body not the blade of those old cheapies. An HDD chassis is a part of a Hard Disk Drive, it holds the disks, the arm and the circuitry together.

 

Hmm, I’m gonna go shave off a piece of my old Western Digital Caviar 21200 and try and burn it, its a whole 1281.9 MB, wow! I wonder if 1995 is old enough

[Pleiades]

Either impure magnesium wont burn, even under a mapp gas blowtorch, or my HDD is not magnesium. A shaving of pure magnesium burned like normal.

[budullewraagh]

a good way to check is to powder it and burn it:)

incredibly pyrophoric.

[raivo]

Most old HDD-s are surely aluminium. It must be some particular brand that used magnesium or maybe those really old HDD-s that had sizes less than 30 Mb?

 

I do not know is this of interest for anyone but i have seen something in shop that was called "magnesium electrode for water boiler". It was aproximately 20 cm length & 1...2cm of diameter. And it was indeed very light magnesiumlike metal. Does anyone know more about such thing?

[Pleiades]

If anyone has any HDDs smaller than 30 megs, they’re more valuable in a museum than your amateur experiments. Apparently you can find bars of magnesium in stores that sell camping supplies for use as ‘fire starters’, but I don’t know for sure cause we don’t have any stores like that here.

 

I’ve never heard of anything called a "magnesium electrode for water boiler", and Google returns very few hits for things like "magnesium electrode".

[budullewraagh]

If anyone has any HDDs smaller than 30 gigs, they’re more valuable in a museum than your amateur experiments.

you mean megs, surely, right?

my father has a comp that has a hard drive of probably just a few megs; certainly under 30.

 

i'll check camping stores for Mg starters

[Pleiades]

oops, yes i meant megs, its edited now