On a related topic, has anyone used any of the heat shield
products (e.g., the one by Vigor that comes in a ReddiWhip like
can -- not as tasty though) while soldering? What have you used
them for -- soldering with stones in place?
For gold rings I use a china cup filled with very wet fine sand,
into which I bury the ring heads. As long as the sand is wet,
temperature doesn't rise above boiling point, so even pearls or
amber will not get damaged (at least this didn't happen to me
for the last 10 years). This works best with a sharp hot flame
and with the joint in the middle of the shank opposite the head,
to be farthest away from the water.
With silver rings, it's another thing, silver is too conductive,
and with massive rings you will not get the metal hot enough,
with smaller rings, it works. I've used those heat shields
occasionally, but if you have to heat the item for a comparably
long time, they "dry out" and loose some of their protecting