Dear Peter,
there is a gentleman in the US by the name of James Binnion who is very adept at this art, I know he has published on it but I have seen his work through a thing called the Ganoksin project, which is an online jewellers forum that has no real boundaries but many very useful bench work videos, artists galleries etc. You should get in touch with him, he is a metallurgist as well as a very talented artist.
This is not really a plug for another forum but it is worth looking at.
Nick