In article ,
Aaron Coolidge wrote:

wrote:
: Copper gaskets can be annealed by heating red hot and quenching in
: cold water.

That's how you harden them.
To anneal them, heat them red hot and let them cool gradually.


WRONG!! Copper behaves the same way as aluminum -- quenching from red
hot results in softening -- not hardening.

Steel wants to cool slowly to soften, though.