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Bezel
Setting Cabochons with PMC
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Big,
beautiful gemstones -- each of us has our own personal
favorite,
a gemstone that’s particularly alluring and enticing.
Caribbean sea-blue larimar, rich, swirling green malachite,
gold flecked royal lapis lazuli – each stone holds
its old mystical and alluring quality. For thousands
of years gemstones have been used for healing, protection,
and adornment.
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As a
metalsmith turned PMC artist and teacher, my natural impulse
was to reach for the torch and silver solder whenever I wanted
to add cabochons to my PMC designs. Most PMC artists, however,
don’t have access to heavy-duty torches required for soldering
bezels in place. This two-part firing technique offers a simplified
method that bridges the gap between metalsmithing and PMC artistry,
a sort of a “hybrid” approach that gives beautiful,
professional results. Because you build the base first and fire
it before the bezel is attached, shrinkage is no longer an issue.
Bezel setting may take
some practice to perfect. But once mastered, you’ll be
setting gemstones with confidence and precision. I recommend
starting with an oval or round stone to gain some experience.
Angular stones can be tricky. You should have a bezel pusher
and/or “rocker,” and many different sizes of bezel
wire to choose from – one size does not fit all. Each gemstone
will have a different pitch or curve, requiring a different height
bezel. Because bezel wire is fine silver, it’s compatible
with PMC and may be fired in place.
• Prepare your
PMC design by rolling out the clay to 5 playing cards thickness.
Low relief textures works best with this process. When preparing
your design it is essential to allow enough space for the shrinkage
that will occur when the piece is fired. Remember, this is a
two-part firing process. If the design is not large enough, you
won’t have enough room to mount the bezel after the initial
firing. You can use a copy machine or computer to approximate
the shrinkage by enlarging the stone by approximately 118%. Lay
this template image over your PMC to get a “guesstimation” of
where the stone will set after shrinkage occurs.
• When building
the bail, be sure to make the back of your pendant perfectly
flat. If there is any “torque” or distortion to the
pendant, the bezel will not lie flat or fit properly.
• Dry, file and
fire. I recommend firing at 1650 for one hour.
• Do not brush
or clean the pendant when it comes from the kiln! Use the “toothiness” of
the unpolished silver as an advantage for adding your bezel.
• Measure the
height of your bezel wire in proportion to the height of the
cabochon. Experience will give you an added sense of the correct
height. Remember, it is always best to use a bezel wire that
is slightly higher than the edge of the cabochon. You can always
raise the stone if it sets too low.
• Measure the
length of the bezel wire just slightly (1 mm) larger than the
circumference of the stone. Use a “Sharpie” to mark
the edge of the bezel wire and then cut. File the edges smooth
until you achieve a perfect fit. The bezel should lift off and
on the stone with ease – not too large, not too small.
• Use oil paste
(made from PMC3 paste and lavender oil) to seal the joint closed.
Take care to avoid using too much paste, which will affect the
fit of the bezel. Use a torch to seal the seam.
**Note: You may also use silver solder to seal the seam. If using solder, the
solder should fill the inside of the seam, hiding the fire scale on the bezel.
You may also use pickle to remove the fire scale.
• Test the bezel
again to be sure it fits properly, easily lifting off and on
the stone.
• Using oil paste,
attach the bezel to the surface of your design taking care not
to distort the shape of the bezel. Also, it is very important
not to attach too much paste to the inside of the bezel wall.
This will prevent the stone from fitting properly, or not at
all.
• Fire again,
1650 for one hour.
• Before cleaning,
test the correct fit of the stone. By placing dental floss under
the stone before placing it into the bezel you can easily remove
the stone it the bezel needs “tweaking.” If the stone
fits, remove it, clean and tumbler your piece.
• Once again,
use dental floss to check the correct height of the stone. If
the stone is too low, use an organic medium such as saw dust
to adjust the height. If the stone sets too low, the bezel will
buckler or have an irregular surface and too much of the stone’s
surface may be obscured. If the stone is set too high, the bezel
will not hold the stone in place.
• Use a bezel
pusher or rocker to “tack” the bezel in at 12, 6,
3 and 9 o’clock. Continue working the bezel around the
stone for a smooth, even fit.
Things you will need:
1. Bezel wire in a variety
of sizes. Bezels wire is fine silver, therefore compatible with
PMC and is readily available from jewelry supply firms. Keep
lots of different sizes on hand.
2. Bezel pushers or
rockers. These tools are sometimes referred to as burnishers.
These versatile tools do double-duty and it’s a good idea
to add several sizes and shapes to your toolbox.
3. Cabochon gemstones.
Cabochons are gemstones that are cut without facets. They come
in all manor of shape and size, including round, oval, and free
form. And even if a stone is “calibrated,” or cut
to industry standards (i.e., 18x13, 18x25, etc.), the height
of each stone may vary. That’s why it’s important
to keep a variety of different sizes of bezel wire on hand.
4. Small, hand held
torch, such as a Crème’ Brule torch or one used
for small soldering job or firing PMC.
5. Firing board for
use with the torch.
6. PMC3 clay and PMC3
oil paste.
Optional: Silver solder.
Originally a traditional
silversmith, Linda Kline’s art took an abrupt turn when
she discovered Precious Metal Clay. The versatile, organic nature
of PCM allowed her to redefine her artistry and capture a look
that had evaded her through traditional metalsmith techniques.
Linda is a Senior Teacher for PMC Connection, lives in Florida
and teaches classes all over the world. To view more of her jewelry
and her current class offerings, go to www.lindaklinedesigns.com
Linda
Kline
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