I don't think many of you know that zinc is also an oxygen
scavenger. I can't give away the technique I use but it involves
zinc removing the oxygen in casting and I get bright silver
casts. If anyone has any metallurgy background maybe they could
illucidate on this point for the rest of us. I do know zinc is
used in the industry but most jewelerys aren't aware of that
In silver alloys, zinc is used for removing oxygen, as you said,
and to reduce the melting range, increase ductility and
resistance against tarnishing, if alloyed to fine silver max.
In gold alloys, zinc gives a better colour in 14kt and reduces
segregation of copper at the grain borders, this way the alloys
get softer and more ductile, you can't temper them like the
usual ternary alloys. In 8kt alloys, it increases the resistance
against sulfur (fine, isn't it - wrong, as the sensitivity to
ammonia is increased, and ammonia is contained in sweat. Try
exposing brass to ammonia fumes and look what happens: it will
crack at points of stress.).
For casting zinc is added in very small quantities as reducing
However, I'm not likely to experiment with adding other metals
to the usual gold-silver-copper alloys, as I don't have any
exact data of how those alloys behave (and believe me, I've got
2 yards of bookshelf length with books about jewellery), and for
trial and error,I don't have the money.