Instructional pages about metal clay and silver clays.
How to work with Silver-Clay
Precious Metal Clay (PMC) and silver PMC+ represent a dramatic development in the handling of precious metals.
PMC consists of microscopic particles of silver or gold suspended in an organic binder to create a pliable material with a consistency similar to modeling clay. PMC can be worked in the fingers and with simple tools to create a vast range of forms and surfaces unobtainable or laborious with traditional techniques.
When it is heated to a high temperature, the binder burns away and the metal particles fuse to form solid metal that can be sanded, soldered, colored and polished like conventional material. This webpage describes some of the techniques devised for PMC and PMC+, and will guide you through your first firing experience.
What Is It?
Precious Metal Clay is a patented material developed by Mitsubishi Materials Corporation of Japan in the early 1990’s. The principle ingredient in PMC is tiny metal particles only 20 microns in diameter. As a point of reference, it would take as many as 25 of these particles to make up a single grain of table salt. The rest of the material consists of water and an organic (naturally occurring) binder. After firing, both the water and binder have been completely removed, so PMC may be hallmarked and will assay as .999 pure. Dried-out PMC or unwanted fired objects can be refined just like conventional precious metal.
The firing process leaves a metal that is less dense than conventional sheet or wire. This means that a piece of jewelry made of PMC is lighter than the same piece made by fabrication or casting. Because it is less dense, PMC is not recommended for applications that require high tensile strength such
as findings. PMC is available in two versions: PMC+, which provides the best modeling ; and PMC3, which is denser, has less shrinkage and offers several firing options. Three years after introducing PMC+, Mitsubishi Materials Corporation developed a second version, called PMC3. Both kinds of clay are worked with the same tools, fired in the same kiln, and can be finished in exactly the same way.
Two Kinds of PMC, one kind of Art Clay Silver
Three years after introducing Original PMC (no longer made), Mitsubishi Materials Corporation developed a second version called PMC+. Both kinds of clay are worked with the same tools, fired in the same kiln, and can be finished in exactly the same way. Everything in this book applies equally to both versions, with two exceptions: PMC+ has a different firing schedule, and it shrinks less.
PMC+ consists of silver particles and organic binders. Because it has a high percentage of metal, the binders and water occupy less space. This means that when they burn out there is less shrinkage. the shrinkage is evenly distributed throughout the piece.
PMC+ is recommended for creating rings and for ..PMC+ is available in lump form, as slip in a syringe, and as paste slip in a jar. PMC+ offers three distinct firing scenarios. When working with PMC+ alone, you'll probably choose the fastest firing schedule. If you want to embed sterling components into the PMC+, fire at the lower temperature of 1470°F (800°C).
PMC3 fires at an even lower temperature (1290 F ) which not only allows implants such as glass, but means alternative, low tech firing devices become possible. (Torch Firing) Not every artist will need all three versions. Some people find a preference and stick with it, while others use different materials depending on the nature of their work.
Art Clay Silver Fires similarly to PMC3 (30 minutes at 1200°F, on a continuum to only 5 minutes at or above 1472°F)