Precious Metal Clay (PMC) is quite a fascinating material. It has
been around in the United States for about 10 years now. People
from all disciplines of arts and crafts are discovering it, we are
becoming familiar with its characteristics, we are beginning to push
the limits, experimentation is alive and doing very well, and there
is so much still to be learned about it. How much more fun can you
have than that? It’s not very often that something as revolutionary
as this comes along in the precious metals world.
Even though its name has the word ‘clay’ in it, don’t think of PMC in
the traditional, earthenware sense of the word. The term ‘clay’ only
designates the consistency of the material. Think of it as malleable
silver and malleable gold. It truly is silver and gold, which is
suspended in an organic binder that burns away when fired. During
the firing (sintering) process, as the binder burns away, the metal
particles bond and fuse together, leaving the final product as pure
(fine) silver and 24K gold.
There is concern in the jewelry industry, ‘how can it be
art?’,‘nothing worth keeping can be made from PMC’, ‘it’s nothing
but junk’, etc. I believe this is an unwarranted fear. PMC opens up
a whole new dimension in metalwork. It is an incredibly spontaneous
way to work, and allows a design to truly evolve, in the purist
sense of the word. True, when we first began working with PMC the
pieces came out looking and feeling rather ‘raw’. But as time goes
by the work is becoming more and more refined. Even though PMC is
incredibly versatile, I don’t see it as replacing metalwork, but
more as enhancing it. There is a lot that can be done with PMC, and
a lot of materials that it can be used in combination and
conjunction with, but every material does have its limitations,
including PMC. And, like any other material, there will be that
work which leaves a bit to be desired, but there will also be that
which is exquisite!
The following chart shows the strength of PMC. As you can see,
there are three formulations. PMC (the first generation), which
includes the 24K gold, is made up of particles that are rather flat,
oatmeal-like shapes. PMC+ (second generation, called PMC plus) is
made of round particles which, as they fire, become more tightly
packed together than the flatter shaped particles do, therefore
creating more strength and density than in PMC. PMC3 (third
generation) is also made of round particles, but the particles are
slightly smaller than those used in PMC+, which creates more
strength and density than PMC or PMC+. The longer PMC is fired, in
particular PMC+ and PMC3, the stronger it becomes, until it is very
close to the strength of sterling silver, which is 10.5 grams/cm3.
PMC
Silver content - 77% by weight
Density (unfired) - 3.5 grams/cm3
Shrinkage in size - 25-30%
Density (after firing at 900C)
fired for 5 minutes - NA
fired for 15 minutes - NA
fired for 2 hours - 7.9 grams/cms
PMC+
Silver content - 90% by weight
Density (unfired) - 6.0 grams/cm3
Shrinkage in size - 10-15%
Density (after firing at 900C)
fired for 5 minutes - NA
fired for 15 minutes - 9.1 grams/cms
fired for 2 hours - 9.8 grams/cms
PMC3
Silver content - 90% by weight
Density (unfired) - 5.5 grams/cm3
Shrinkage in size - 10-15%
Density (after firing at 900C)
fired for 5 minutes - 9.3 grams/cms
fired for 15 minutes - 9.5 grams/cms
fired for 2 hours - 9.9 grams/cms
Density (after firing at 700C)
fired for 5 minutes - 8.2 grams/cms
fired for 15 minutes - 9.1 grams/cms
fired for 2 hours - 9.5 grams/cms
PMC also has several firing times and temperatures. These allow for
quite a bit of versatility in the ways that PMC can be used, and in
the methods of application. For instance, in a PMC piece fired at
1650F only cubic zirconia or lab grown corundum can be used.
However, in PMC3 fired at 1110F stones such as peridot, moonstone,
certain garnets, and even tanzanite and diamonds can be fired in
place. Dichroic glass can be successfully fired in a PMC3 piece at
1200F-1225F.
Standard Gold PMC
Fahrenheit - 1830
Centigrade - 1000
Time - 2 Hours
Standard Silver PMC
Fahrenheit - 1650
Centigrade - 900
Time - 2 Hours
Silver PMC +
Fahrenheit - 1650
Centigrade - 900
Time - 10 Minutes
Fahrenheit - 1560
Centigrade - 850
Time - 20 Minutes
Fahrenheit - 1470
Centigrade - 800
Time - 30 Minutes
Silver PMC 3
Fahrenheit - 1290
Centigrade - 700
Time - 10 Minutes
Fahrenheit - 1200
Centigrade - 650
Time - 20 Minutes
Fahrenheit - 1110
Centigrade - 600
Time - 30 Minutes
And, besides the firing process, PMC+ and PMC3 can be torch fired.
PMC can be soldered, which allows for attaching to other metals.
PMC silver and gold can be combined with each other in various ways
into the same piece for stunning, two-color effects. Silver PMC,
being fine silver, is perfect for enameling. So, in our quest for
creative outlets, PMC has a wonderfully unique potential that is
just waiting to be discovered by our own individuality. The
question is?are we ready to get started?
Jeanette Landenwitch
http://www.jmlcreations.com