On Wed, 3 Dec 2008 14:59:08 -0800, "Calif Bill"
wrote:

Magnesium melts. One of the
reasons it is so hard to weld magnesium.

You are saying that melting makes things hard to weld?
I say it is quite usual to melt the metal while welding, although
there is pressure welding, below the melting point, sometimes even at
room temperature. And it isn't hard to weld magnesium. You simply
surround the arc with a blanket of inert gas, helium or argon.
Nitrogen and carbon dioxide are not inert enough, magnesium will burn
in either.
I have a welded magnesium extension ladder, and I once ignited a small
sliver of it. It burns with a brilliant white light.

Casady