How to Use Precious Metal Clay (PMC)
All you need to know about working with PMC:
Printable booklet with all information in this section (PDF, 838 KB)
Printable booklet: 'Welcome to BRONZclay — An introduction to the tools & techniques for working with BRONZclay' (PDF, 600 KB)
Introduction: How Does PMC Work?
Under the proper conditions, particles of metal fuse together in the same way that droplets of water run together to make larger puddles. In the case of metals, oxides (tarnish) that form naturally on most metals prevent this from happening. The solution here is to use precious or noble metals in their pure state. These do not readily oxidize so even at the high temperatures needed to induce fusion they remain free of coatings. This explains why there is not a brass or sterling version of PMC — short of firing it in a vacuum, it won’t work.
Form
Using very simple tools and your own very talented 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 spontaneous and liberating process.
Fire
After it has dried, the PMC object is taken to a specific heat (as described in "Firing Tools"). This drives off whatever moisture remains, then burns off the binder, which dissipates as a harmless smoke. At this point in the firing process, the PMC is a fragile, porous metallic husk. At higher temperatures, the particles melt together and form a solid, dense metal. Depending on the type of PMC, this can take from 10 minutes to two hours.
Finish
After firing, the object can be handled like any other gold or silver item—it can be soldered, burnished, buffed, tumbled, plated and so on to achieve any finish you want.