What is PMC?

Precious Metal Clay (PMC) is an innovative development in the handling of precious metals. PMC consists of microscopic particles of silver or gold suspended in a binder to create a pliable material with a consistency similar to modeling clay. PMC can be worked with the fingers and simple inexpensive tools to create a vast range of forms and surfaces that would be unattainable to the average jewelry maker without a huge workbench of tools and decades of experience in metalsmithing.

When heated to a high temperature, the binder in PMC burns away and the metal particles fuse to form solid metal that can be sanded, soldered, colored and polished like conventional metals.

A short history

Precious Metal Clay was developed by scientists working at the Mitsubishi Materials Special Products division in Japan. The first patents were awarded in the early 1990s. The principle ingredient of PMC is gold or silver, reduced to tiny flakes smaller than 20 microns in size.

The other ingredients in PMC are water and an organic (naturally occuring) binder. After firing, the water and binder are burned away so what remains can be hallmarked as .999 silver or gold. Dried out or unwanted objects (or design mistakes) can be refined and reused just like conventional precious metal.

Form

Using very simple tools and your own fingers, PMC is rolled, pressed, squeezed, layered and molded into a desired shape. Parts can be added, removed and refined as you go, making this a highly organic design process that can be built upon as design inspiration strikes.

Firing

After it has dried, the PMC object is taken to a specific heat. This drives off what moisture remains, then burns the binder. This goes off as a harmless smoke. At this point the PMC is a fragile porous metallic husk. At higher temperatures the particles melt into one another to form a solid dense metal. Depending on the type of PMC, this can take from 10 minutes to two hours to properly fire PMC.

Finish

After firing, the object can be handled like any other gold or silver item. It can be soldered, burnished, buffed, tumbled or plated, depending on the look you are going for.

Three kinds of PMC

The Original has the best working properties and remains moist a bit longer than the others. It shrinks about 28%, so textures and details are enhanced after firing. Objects made on original PMC remain slightly porous even after proper firing. This means they are lighter than the same size object made of wrought silver, but also means strength is reduced.

PMC Plus is made of a differently shaped metal particle and contains less binder. The shrinkage rate is 12-15%. PMC Plus offers three distinct firing options, two of them at lower temperatures than the original. Objects made of PMC Plus can go from clay to metal in as little as 10 minutes. This material is about 10% more expensive than original PMC.

PMC3 is the third member of the family. It is as dense as PMC Plus, fires as fast, but does all this at remarkably low temperatures. Three distinct firing options provide a range that makes this especially useful for co-firing glass, findings and some stones.

There is a PMC out there for you and the work you want to do. Check my auctions for PMC tools and supplies.