Precious Metal Clay: A Material Used by Artists

Precious metal clays were first developed in the early 1990's in Japan as silver metal clay, or precious metal clay (PMC). Metal clays have microscopic particles of fine metallic powder suspended in an organic water-soluble binder.  The binder will burn off during the firing process leaving the manipulated metal behind. This material is used to make beads, jewelry and other decorative works. Metal clay is available in fine silver, sterling silver, gold, steel, copper or bronze.

Shaping metal clay is similar to working with any soft clay.  A method commonly used among clay artists of using impressions to create design and texture can be applied to these metals which would require casting in other types of metalwork.There is an air-drying period after shaping during which most of the water evaporates. The air dried clay is stiff like hardened leather and at this point it can be carefully sanded or carved to a finer level of detail.  The dried clay, having been shaped and detailed is then fired in a kiln. The binder burns away, leaving behind pure metal. The artists know to expect that there will be a degree of shrinkage, usually between 10-15%, and plan their designs accordingly.

Silver metal clay results in objects that are are ideal for enameling. Of the brands available the most commonly used are Precious Metal Clay (PMC) and Art Clay Silver (ACS):

• The base formula of PMC is what is now considered “standard.” It has a firing temperature of 1650F and a high shrinkage rate of approximately 30%. Two additional subsequent versions have been developed called PMC+, which is fired at 1490F and PMC3, which is fired at temperatures as low as 1100F. The later versions of PMC have a reduced shrinkage rate resulting in designs produced in finer detail.
•  ACS, also developed in Japan, has a similar consistency to PMC+. ACS has the outstanding characteristic of being fired using a hand-held torch or regular kitchen-oven. There are subtle differences in the binder components and longer firing times, attributing to the bonus of having a much lower shrinkage rate of only 8-10%. An artist working with ACS can create more fine detail without losing the definition of the finished piece.

Metal clays allow metal-smithing without use of hammers or pitch as the material is as malleable as regular soft clay.  The end resulting pieces are polished to a luster easily comparable to cast metal. These clay products have been developed to produce a high level of detail in metal art. The types mentioned here have their particular advantages, yet it is a personal decision which metal clay an artist chooses to incorporate in their design. This is a relatively new medium to work with that has results both of high quality and beauty.

If you would like to browse a selection of PMC options to use in your own metal art, click the Delphi link below and search for "pmc metal clay"

© Rebecca H Knight, images are © their respective owners. All rights reserved.

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