Welcome to PMCinsider.

This Website is dedicated to learning everything about our products—Precious Metal Clay®—with instruction on how to use them effectively.

Precious Metal clay is a crafting medium consisting of very small particles of metal—providing both silver and gold types—mixed with an organic binder and water for use in making jewelry, beads and small sculptures. Originating in our Japan factory in 1990, metal clay can be shaped just like any soft clay, by hand or using molds. After drying, the clay can be fired in a variety of ways such as in a kiln, or with a handheld gas torch, depending on the type of clay and the metal in it. The binder burns away, leaving the pure sintered metal. Shrinkage of between 8% and 20% occurs (depending on the product used). Alloys such as PMC Sterling 925 and PMC OneFire Sterling 950 also are available.

 

History of Precious Metal Clay (PMC)

Metal clay first came out in Japan in 1990 to allow craft jewelry makers to make sophisticated looking jewelry without years of study most people need to make fine jewelry.

Objects made from fine silver metal clay contain 99.9% pure silver, which is suitable for enameling. Lump metal clay is sold in sealed packets to keep it moist and workable. The silver versions are also available as a softer paste. It comes in a pre-filled syringe which can be used to produce extruded forms and it also comes in small jars of slip. There are paper-like sheets of PMC—from which most of the moisture has been removed—that can be used for origami and appliqué.

Metal clay artists looking for more strength in their silver creations can either mix equal parts of PMC fine silver clay with PMC Sterling clay or purchase it as PMC OneFire Sterling 950. Because the clay is a sterling silver alloy, one of its best attributes is its superior post firing strength in comparison to fine silver. This clay is fired on a raised, open shelf at 885°C (1625 °F) for 1 hours, full ramp. No carbon required. Its shrinkage rate is approximately15–20%.

 

The PMC Product Family

PMC was developed in the early 1990s in Japan by metallurgist Masaki Morikawa. As a solid-phase sintered product of a precious metal powder used to form a precious metal object. The material consists of microscopic particles of fine silver or pure gold and a water-soluble, non-toxic, organic binder that burns off during firing. Success was first achieved with gold and later duplicated with silver.

The PMC brand includes the following products:

  • The original formula of PMC, was called "Standard" (discontinued). PMC+: fired at 900°C (1650°F) for 2 hours or 800°C (1470°F) for 30 minutes; shrinks 15%, due to a particle size reduction.
  • PMC+ is also available in sheet form which can be worked like paper; for an example, origami. PMC3 & PMC Flex: fires at a range of temperatures/times—from 599°C (1110°F) for 45 minutes to 900°C (1650°F) for 2 hours and shrinks by 10%. Small pieces can also be fired using a butane torch by heating it to orange heat for at least 5 minutes. It has a longer working life than the older formulations. It is also available in thick slip (paste forms) which can be used for connecting clay parts or painted onto the surface of an object to create a relief design.
  • Aura 22, a 22-carat gilding material is a gold paste intended to be painted onto the surface of silver PMC pieces, or ready-made silver objects.
  • PMC Pro (discontinued), a harder product which is only 0.900 fineness silver, hence it cannot be hallmarked as sterling silver.
  • PMC Sterling (925) is fired at 815°C (1499°F) and shrinks by 10–20%. Because of the copper content in this formula, firing is a two-step process. Step one is an open-shelf firing and step two requires a firing pan with activated carbon media.
  • PMC OneFire Sterling (950) is a versatile PMC. It's been formulated so that it can be fired without carbon in the open-air at 885°C (1625°F) for 1 hour, it comes out of the kiln as a sterling silver object.
  • PMC 22k Gold is the strongest PMC material. It can be torch and kiln fired 700°C (1290°F) for 90 mins.; 900°C (1650°F) for 10 mins.
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