Hi Sigrid, I think this has been covered pretty exhaustively in the
past... check the Orchid archives... I believe a soak at 650 deg. F.
for 2 hours or more... but check to be sure.
I am writing to add in the June 2001 issue of SNAG (Society of North
American Goldsmiths) News there is a Tech News article by Jeff
Herman, executive director of the Society of American Silversmiths
regarding Argentium(r) sterling silver. This is apparently fine silver
alloyed with germanium, as opposed to copper, which provides some
interesting characteristics. The article goes on to discuss working
properties, fabrication and forming, casting, annealing and soldering
and so on, including heat hardening.
What I found very interesting is that this new sterling alloy can
apparently be heat hardened at 450 deg. F., which puts it in the range
for any standard kitchen oven!
According to the article, there is limited availability of sheet to
SAS artisan members, and plans are underway to find a U.S. fabricator
for mass production.
Here's a URL to an updated version of the article I founds on the SAS
All the best,