The first type of metal that was used in this way was pure (24k) gold, developed and manufactured by Mitsubishi Materials. This was followed with pure (.999) silver and marketed to the Japanese craft community as Precious Metal Clay (PMC) - a brand name. Soon another company, Aida Chemical Industries, developed a similar product called Art Clay Silver (ACS).
In 2006 Metal Adventures debuted a bronze version called BronzClay and soon after followed with CopprClay. Since then many more manufacturers have entered the metal clay landscape to offer a variety of base metal clays including rose bronze, steel, and brass. Base metal clays are different from fine silver clay in that they need to be fired in an oxygen free atmosphere to sinter correctly.
All metal clays can be worked wet or dry using a combination of techniques which include pressing or rolling a texture into the moist clay, carving dry clay, and forming 3 dimensional shapes in either stage. During the firing process, work shrinks anywhere between 8 and 30% depending on the type of clay (clay body) and specific firing process used. Gold, silver, and some copper metal clays may be fired with a butane torch or in a kiln, but most base metal clays and alloys of silver must be fired in a kiln, submerged in granulated carbon. PMC carries a sterling silver clay (.925) alloy which must be fired in a manner similar to base metal clays. 'Enriched' sterlings like .960 can be kiln fired without carbon (referred to as an 'open firing').
Some metal clay companies offer powdered metal pre-mixed with binder that the end user combines with water to create a malleable material. Others sell ready-made lump clay. There are also some alloys that one can blend in the studio. One of these is .960 sterling, which is an equal combination of .925 Sterling clay and PMC3, PMC+, PMC Flex or ACS. This alloy is stronger than fine silver alone, and while not quite as strong as .925 Sterling, can be fired on an open shelf with no carbon.
The possibilities of creating jewelry and small scale sculpture with metal clay is endless, and as such a young art form – new designs and ideas are being developed every day.