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Heating stones to make seats in wax


#1

Hello everyone.

I have a question about carving wax settings.

When carving some settings, like a bezel for a fancy shape faceted
stone, I like to carve out a lot of the wax for the stone seat, then
put the stone in the depression and use my wax pen to heat the stone
and melt a seat for it. After that, take the stone out and finish
carving the setting. I have done this a lot with diamonds and
corundum, because i know they can take the heat. But I am wondering
if it is ok to do this with other stones? Its so much easier to carve
the setting this way, but I don’t want to risk damaging a customers
stone. I use Matt green carving wax, so the melting temperature is
around 230F. So I am wondering how much heat is ok for heat
sensitive stones?

At the moment I have to make several bezels for tourmalines. Thank
you.

Jon


#2

Hello Jon;

I would avoid putting that kind of heat on anything you’re not
certain can take it, so that kind of limits you to diamonds,
corundum, and moissonite. However, there is a way to work with some
stones that can take some heat but not a lot. This would include
garnets, perhaps tourmalines (but certainly not bi-colored ones),
amethyst, citrine, etc. Avoid opals, tanzanites, and emeralds, etc.,
the really sensitive ones.

First, carve a seat that is significantly larger than your stone, in
your carving wax, of course. Then, build up the inside of the seat
with a lower temperature wax such as injection wax. Now, coat your
stone with a lubricant such as silicone spray. Put the modified wax,
stone pressed into place, under a heat lamp. Not too hot, just don’t
get the lamp right down on the stone. After a bit, the softer wax
should soften and you can press it down into the wax to form the
seat. Let it cool completely, and either push the stone out from the
back or use some bees wax to “pluck” it out of the seat. If you have
a stone you’re not sure of, see if you can find a cheap version of
the same material to experiment with.

David L. Huffman


#3

Yes Jon, most of the heat sensitive stones can take the heat of (low
temperature) melted wax. I would avoid using the hard high temp
carving waxes for melt in seats and also watch your pen tip, as you
know, its much hotter than the melted wax itself. I have done this
carefully with opals,emeralds, and most other colored stones. I
(don’t) however heat the stone itself! I make the wax with a lose
seat and flow in a lower temparature wax. Usually a 150 degree waxpot
wax or the quick melting hard purple stick wax. I’m sure there are
several low melt waxes you can find in your tool catalog. After I
melt in the wax, I pop out the stone and cut away any flashing. When
I am melting the wax, I keep my finger on the top of the stone to
feel any heat coming through the stone. If the stone gets too hot I
stop and let it cool down. This rarely happens since I am using such
a tiny amount of wax, just enough to fill in around the seat from
underneath. I do this with cabs and fancies also. After casting you
sometimes have to clean up the seat and enlarge it in select areas,
before setting due to shrinkage but at least you have something to
go by to match the stone with. These days, I am often able to carve a
seat that is very close to the actual stone so my melt in process is
minimized. Try using this method with less expensive and smaller
stones first, just to prove it to yourself and give yourself some
feedback on the heat parameters. One final point, I had the recent
occaision to use someone elses wax pen in their shop and the setting
was being used all the way to the highest heat. This was with a foot
pedal setup. I am not sure why they did this except perhaps for
speedy heating. This, however is (not ) the way to use a wax pen. Set
your pen temperature to just hot enough to melt the wax you are using
when the pedal is on. This way, you’ll avoid the red hot, smoking
wax pen tip that can damage heat sensitive stones. Hopefully, this is
of some help. You are wise to avoid excessive heat swings either way
and your question shows you are aware and should have no problems.

-charles


#4

Dear Jon,

I have used the method of heating a gemstone to confirm the seat
when carving wax bezels. I have used it with fancy cut tourmalines and
I thought it very helpful, If you are setting your own stones and
find it helps. more power to you.

One caution, The melting temperature of the wax is not as important
as the heat of your wax pen.

If you use your wax pen tip to warm the gemstone, the wax pen tip
can get much hotter than the melting temperature of the wax and it is
very small, concentrating that heat in a small area, this may cause
some thermal chipping / cracking at facet junctions where the
gemstone is most vulnerable.

Tourmalines scratch easily so be careful cleaning any residue wax
off the table and crown facets.

Nanz Aalund
Associate Editor / Art Jewelry magazine
21027 Crossroads Circle / Waukesha WI 53187-1612
262.796.8776 ext.228