I often use a wax pen to heat a stone and seat it in the wax.
That's a risky technique with a lot of stones. I can almost
guarantee you'd bust a tanzanite or an opal doing that, they're very
sensitive to abrubt temperature changes.
Are there any tricks you once used, but discarded as being off or
wrong or risky?
Here's one that's somewhat less risky. Cut the seat sloppy large,
then fill it with a layer of lower temperature wax, then, spray the
stone with silicone and put it in the seat and put the whole thing
under a heat lamp (a light bulb will do). That will raise the
temperature less and more slowly. When the low temp wax seat softens,
push the stone down into it and let the wax cool. Pluck out the
I've done a fair amount of concave cut stones, once setting a
concave cut Helenite (glass) in a heavy white gold bezel. Here's what
I lay the stone upside down on the wax with a bit of super glue. When
the glue sets, I trace around the stone with a needle. Take off the
stone and cut a seat, checking the fit from time to time with the
stone. As I get closer, I spray "Seat Check" in the seat. The
product is available from Rio Grande, it's developed for the dental
industry. Press the stone in the seat with a little pressure and
where it makes contact, the Seat Check darkens. Cut the dark areas
and spray and check. Cut the new dark areas. Continue in this way
until the stone darkens the entire seat. After it's cast, you need
only remove a bit of the surface casting skin to have an excellent
So basically, I'm telling you the secret, which will no doubt
dissapoint some. The secret is patience. If I come up with something
better, I'll let you know, but I might request payment first. I'll
give away general knowlege, because you'll pay for that with years of
practice. Shortcuts are different.
David L. Huffman