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This is the basic recipe for
the iridescent patina. This patina is most effective on highly textured
pieces, such as torch texture, rollerprinted and reticulation. It has a
slight color interference pattern, similar to oil on water. It has a high
natural luster, similar to the nacre on pearls, if done correctly with many
repeated dips in a weak solution. It is durable, the colors remain stable
to a high degree, and very slow (years) to darken or further oxidize. Further
oxidation can be prevented entirely by applying Renaissance Wax when the
patina is dry. It is effective on silver, brass and copper, to a lesser
degree with gold. This makes it an excellent patina for keum-boo applications,
since the 24 kt. gold content remains bright.
Your metal should be thoroughly clean. Wash, or use an ultrasonic, to
cleanse off surface dirt and oil, then rinse with clean water. Brass brushing
the surface is perfectly acceptable, and provides more surface tooth.
The big secret is the addition of two mordants to enhance and stabilize
the colors. I usually use salt and ammonia. The recipe I use most frequently
is:
- 1 small piece of liver of sulfur
- about 1/4 inch in diameter
- 2 C. hot water
- 1 Tbsp. clear household ammonia
- 1 tsp. salt
Mix the salt and ammonia with the liver-of-sulfur
Your solution should be a very pale straw yellow color. If the solution
is too strong, the colors will work too fast. Add additional water if
you need it. Iodized salt gives a different effect than kosher salt, each
intensifying certain colors the other doesn't.
Now you need to set up your dipping station, lined up in a row, so you
can progress from one step to the next, quickly and efficiently. You need
a pot of very hot water and bowl of very, very cold water. Your dipping
station will be lined up in a row, from left to right: pot of very hot
water, hot liver-of-sulfur solution, bowl of very ice-cold water. First
dip your metal into the hot plain water to warm up the metal. The warmer
the metal is, the more intense the effect and the more quickly the liver-of-sulfur
solution works. Then quickly swish it through the liver-of-sulfur solution,
then quickly put it in the cold water to stop the action. Do not leave
the piece in the liver-of-sulfur solution for any time waiting for the
colors to develop. The color will finish developing in the cold water.
Repeat until you get the colors you want. The color range is predictable.
First yellow, then green, red, blue, purple, and black. You can have several
different colors in one piece by selectively dipping just one part of
the piece.
Caution must be used with pieces that have heat sensitive stones, or
stones which cannot take thermal shock well, such as opals. However, I've
been successful, even with delicate stones, by not getting the metal quite
as hot when dipping and working more slowly. I have used this process
with pearls, turquoise, fire agates, malachite, rhodonite, corundums and
beryls, with no ill effect to the stones. However, I would be reluctant
to use the process with say, a heavily included emerald, simply because
the thermal shock could cause the emerald to fracture.
After you have achieved the colors you want, wipe the metal dry with
a soft cloth. Allow to continue drying for several hours. If you wish
at this point, you can "knock-back" the patina on the high points
with a little rouge on a felt buff, so you have the contrast of the bright
silver against the color. Clean the metal again, and apply a high quality
wax, such as Renaissance Wax, or cabinet-grade lacquer. Wax will dull
down the colors a bit, and lacquer will brighten the colors a bit. For
things that will be subjected to a high degree of wear, such as bracelets
or rings, you may want to incorporate guard wires during the fabrication
of the piece to protect the patina from abrasion. However, on something
like reticulation, where there are natural hills and valleys, the valleys
naturally retain the patina, while the high points become bright and shiny
with abrasion, providing a very lovely contrast. Hope you have fun playing!
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