This happened last weekend.

I was making a mount that would allow me to put an old Evinrude engine on a
canoe. I grabbed a piece of angle that has been lying around my shop for
about thirty years, used as a prybar, etc. I had always assumed that it was
aluminum.

I sawed it into the shape I wanted and then finished the edges with a
grinder. After I dressed it out like I wanted it, I started in on my next
project, a skid plate to go under my propane tank. As soon as I started in
on the steel, the whole workbench lit up in an intense glow for a few
seconds. I managed to get away without having holes burned in my shoes or
setting the workbench on fire.

Be careful when working with magnesium and then working with steel! This is
one case where it really pays to clean up early.

Jim