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Cabochon backing material


#1

I know this subject has been covered numerous times on this forum;
however, I have not seen this material mentioned before. Last year
while on a buying trip, I was fortunate enough to meet a son-in-law
of the King family who owns the Kings Manassa Turquoise mine in
Manassa, Colorado. He was kind and gracious even showing me his
turquoise cutting operation, which is to say the least quite large.
One of the things I noticed, was the backing material on his
turquoise cabochons. It was a light brown. I failed to ask him what
he used. This year, on a similar buying trip, I found myself in
Thunderbird Supply in Gallup, New Mexico. While there, I ran across
turquoise cabochons with this same backing material, and asked if
anyone knew what it was and who cut these cabs. I was told that it
was my new acquaintance in Manassa, and that it was doping wax with
epoxy added. I know this is a long way around my question of, has
anyone on this forum used this, heard of it before, or know the
formula or composition? I have misplaced his address and phone
number, or I would ask him. Over the years, I have used everything
from Devcon Plastic Steel to old 78 rpm records and lots of others in
between, but find this intriguing. All replies appreciated.

John Barton


#2

John,

The material is not a dopping wax and epoxy mixture, although I
almost fell off my chair laughing when I read that.

The material is just good old devcon “liquid bronze” a metal filled
epoxy putty.

To back stones first slice or select turquoise of the desired
thickness. Lay down a full square of aluminum foil or wax paper.

Mix the devcon and spread it out over the wax paper/aluminum foil
with a disposable plastic spatula about 3/16 - thick.

place your turquoise slabs/nuggets cutting surface up into the
devcon. push down a little and move the stone around a little to make
sure you have a good seal on the bottom side.

In the alternative you can place dollops like cookie dough, and place
individual stones onto the dollops.

Place all of your pieces just far enough apart so that you can
separate them with a lapidary saw when the backing hardens.

Use a lapidary saw to separate the backed stones and trim for
cutting.

if you are old fashioned, you can then dop them with wax, or if you
are lazy like me - use a dab of hot glue, and substitute a sturdy
nail for the wooden dop stick. The nail will conduct heat from the
hot glue, and allow it to set more quickly.

You can also use super glue to adhere the nail (dop stick) to the
stone, but you will have to heat the nail (at the other end) with a
torch (in an extremely well ventilated area) when you want to break
the bond quickly.

There you have it. The secret finally revealed!

I rather suspect the cutters are using the bronze backing because
they have found it weighs more, and turquoise cut in this fashion is
sold by the carat;) Otherwise you could just use Devcon “plastic
steel”.

Below is a link to a company that sells the stuff.

http://tinyurl.com/4jf8t8

Happy cutting!

Michael Rogers
M. M. Rogers Design
Albuquerque, NM


#3
I rather suspect the cutters are using the bronze backing because
they have found it weighs more, and turquoise cut in this fashion
is sold by the carat;) Otherwise you could just use Devcon "plastic
steel". 

That’s interesting Michael. I never sell backed stones of any kind
by the carat and thought that was an industry-wide practice. I price
all opal doublets by the piece as well as turquoise backed by Liquid
Steel.

Rick Martin
www.artcutgems.com


#4

My thanks to Rick Martin & Michael Rogers for their replies to my
question regarding backing material. After I posted the question, I
finally found the address & phone number of the turquoise cutter
(son-in-law of the King family) I had met in Manassa Colorado. I
posed the question to him and like myself, he never uses Devcon. He
cuts more cabs in a day than most cutters in a month. When I was
graciously shown his operation, I was overwhemed by the size of his
operation, literally thousands of cabs both finshed and dopped.All
very high grade and gem grade turquoise. He has his own formula for
backing material and colors it based on the cabochons matrix
color.He shared the formula with me but the componets are in such
large quantity, it would be almost impossible for me to break it down
to my size needs. He did give me some good ideas for creating my own
backing material since I too want to color mine to compliment my
stones…

While on the subject of stones, for those of you who have gotten into
using Utah dinosaur bone, while on a buying trip out to Utah last
month, I found that our old friend and the master of dino bone
hunters and collectors Ernest Shirley passed away last May. I talked
to his son Tom and he was closing the shop in Hanksville the next
day. May Ernest rest in peace.

Thanks again
Rick and Michael.
John Barton