"Richard Casady" wrote in message
...
On Wed, 3 Dec 2008 11:27:14 -0800, "Calif Bill"
wrote:

I think the Sheffield was mostly steel and the aluminum in question was a
high magnesium content alloy.

Probably no more than 5%. The stuff, and copper as well, harden
aluminum as carbon hardens iron.

Casady

Won't be any copper to speak of in aluminum exposed to sal****er.