From: gwhite@tiac.net (Doug White)
Newsgroups: rec.crafts.metalworking
Subject: Re: Casting magnesium
Date: Wed, 11 Mar 1998 13:23:24 GMT

In article <Epn3o7.9s5@world.std.com>, dp@world.std.com (Jeff DelPapa) wrote:
>In article <6e5245$2pp@bgtnsc03.worldnet.att.net>,
>Gary <nospam@netcom.com> wrote:
>>Possible to cast magnesium in a home foundry?
>>
>>If not, how is it done commercially?
>>
>
>Got a fireworks license?  I have tried a lot of dumb things in my day,
>but I draw the line at liquid magnesium. If I had some overwhelming
>reason to try it, I would try to melt and pour in a vacuum, or at
>least a box full of argon.
>
>From what I hear, casting magnesium is an inexact science, and every
>now and then something explodes, so you have to have a foundry built
>to take it.  And even when it doesn't explode, uniformity is hard to
>come by.
>
>The only use I have found to date for magneisum is as a fuse for
>thermite.  I pretty much intend to keep it that way.

First of all, magnesium doesn't 'explode', it just burns like hell.  It
is, in a manner of speaking, possible to do this in a small foundry, but
only if you like excitement.  I've seen it done by accident in my junior
high school.  We would get our aluminum for castings from the local
surplus yard, and one day a sizeable amount of magnesium got into the mix
by mistake.  I have no idea how much of the pot was magnesium, but once
it melted, it caught on fire in the crucible.  They managed to get the
crucible out & pour the stuff into ingots, which cooled it down to the
point where it would no longer burn.  The intense white flames faded the
color from the walls in that corner of the room.  They used to be pale
yellow, and until they repainted, were very white.  I also seem to recall
that the crucible was spitting little bits of flaming material during the
process, and there were little zorch marks all over the place.
Fortunately, no one was hurt.  I don't know how much worse it might have
been if there had only been pure magnesium in the pot.  I'm assuming that
there was at least some aluminum in there with it.  The resulting ingots
were quite light, but porous & brittle.

Doug White