I wouldn't recommend acetylene as a good gas for doing ANY work on silver: it combines chemically with silver when at high temperatures. This is the primary cause of fire scale in silver and its alloys.
In fact acetylene is perfect for silver whether it be sterling or
fine. Acetylene does not cause fire scale, improper preparation of
the sterling causes fire scale. Prips flux properly applied
(discussed hundreds of times on Orchid) works 100% of the time to
prevent firescale on sterling. We have been fabricating and repairing
silver of all sizes and types (as well as gold) for 28 years. In
fact, all local jewelers refer their silver repair customers to us
because we know what we are doing. Darn acetylene!
Gary
Janine’s Jewelry
Redding, Ca.