How to Use Precious Metal Clay
Make Unique and Wonderful Items of Jewelry with Silver PMC
Mar 17, 2007
When hearing about precious metal or silver clay (also known as PMC) for the first time, people will look slightly incredulous and immediately conjure up visions of some form of alchemy – and indeed, this isn’t too far away from the truth! Silver clay is a clay substance that when heated turns into pure silver. This, of course, is oversimplifying things – and it is not just any old clay, this ‘clay’ is made from masses of tiny pure silver particles that are held together in a binder. When heated the binder burns away and the particles fuse together to form a solid piece of pure silver. The beauty of this is that the clay can be molded and formed like any piece of ceramic or polymer clay, and intricate, beautiful items of silver can be made.
When silver clay was first invented – back in the dark old days of the early 1990’s - the process of making items was the same as it is today, however the clay was less user friendly. The firing process needed to take place at much higher heats than is necessary for today’s silver clays and therefore a kiln was essential. Continued research and development has resulted in a range of clays that are much easier to fire. Some can even be fired with a normal gas blowtorch – or even in a gas oven! This makes these clays a lot more accessible and can be used with very little in the way of specialist or expensive equipment.
The original silver clays are still available, however the new formulations offer, perhaps, a better choice for someone working with the clay for the first time. Another feature of the new formulations is that the clay has less shrinkage. Whereas all silver clays have some degree of shrinkage, the original formulations will shrink by up to about a third, the new formulations shrink at a stated rate of between 10% and 15%, depending on the brand.
The most reliable method of firing the clay is still by kiln, where the temperature can be controlled. If the temperature is too low the binder will not completely burn off and the finished piece will be weak; if the temperature is too high then the silver will melt completely, leaving you with a blob instead of a neatly molded piece of silver. However saying that, many silver clay artists have great success with using a blowtorch or oven – so it is best to read up about it and see which is the best option for you.
Once fired, quite honestly, the silver item looks pretty unprepossessing! It will have a dull matt surface and won’t look anything like the gleaming silver piece you had anticipated. Don’t worry!! All the piece requires is a clean and polish and it will be finished. It can be polished quite simply using a tumble polisher, and flat pieces can be ‘burnished’ with the back of a spoon to raise a shine.
The finished piece can be used like any other item of silver. Beads can be strung and worn, and other items can be drilled into or soldered. When soldering finished silver clay pieces, you will find that the silver is slightly more porous than other silver, and as such it is best to burnish the area prior to soldering. The good news is being almost pure silver you won’t need to worry about fire stain!
Silver clay is widely available from craft and jewelers supplier stores. There are two main brands – Precious Metal Clay (PMC) and Art Clay Silver. Gold clay is also available, however the cost is significantly higher than the silver clay, hence most people prefer to start with the silver.
More information can be found at the PMC Guild and also at the Society of American Silversmiths,
An interesting project working with polymer clay to make a lapel pin can be found here.
