"William Wixon" wrote in
:

snip
hey, i guess for that matter, aren't some u.s. coins bimetallic?

i know they can get dissimilar metals to stick together using
explosive welding, but how to they do it otherwise? that's, as far as
i know, a very rare and extremely limited technique.

US coins used to be explosively welded. I assuem that is still what they
do. The use large thick sheets, and then roll them out thin. That way
they get a lot of welded metal per bang.

Doug White