Hardening bronze for tools

Earlier on Orchid there was a recommendation for the book Silverwork
and Jewellry, by H. Wilson as a source for patinas. It was a great
recommendation, thanks! For anyone else interested, be sure to get a
copy of the second edition. I originally had a copy of the first
edition which does not include the info on Japanese alloys or

On page 368, in reference to bronze, it is mentioned that tin will
sweat out to the surface, if the metal is overheated. The goal is to
avoid this if trying to apply patinas as it makes the surface hard.
This comment is then footnoted to describe that the Egyptians used
this feature to harden edges on bronze tools. How hot does the bronze
have to get to have this happen? Is the surface hardening sufficient
for small stamps or punches? I don’t have any bronze currently. Is it
worth picking up some for tool making?

Teri Jo
Chandler, AZ