A New Kind of Gold: Who Kneads it?

Do-it-yourself and jewelry making novices take note: now you can make pieces just like the pros. Mitsubishi Materials Corp. of Japan has invented Precious Metal Clay, patented worldwide, that can be squeezed, pounded, rolled or otherwise squashed into shape, then fired in a kiln. After three hours or so, out comes a piece of jewelry made of gold, platinum or silver. The clay is also available in sheets, thicker than paper but thinner than mat board, that can be folded like origami paper.

The substance consists of tiny particles of metal suspended in an organic medium. In the oven, the medium burns off and the particles sinter, or bond, into a solid metal mass. Metallurgically, the metal is the same as the stamped or cast kind, although it is 20% to 30% less dense. The gold clay comes in 18k and 24k (the former is available in yellow, rose and white; the latter in yellow only). The white-metal varieties have the light grayish color of unfired porcelain; the gold version that of ocher.

The clay has been available in Japan, Germany and the United Kingdom for several months. Tim McCreight, a U.S. goldsmith from Cape Elizabeth, Maine, who is working for Mitsubishi as a consultant, says negotiations are now underway between Mitsubishi and a potential U.S. marketer for the clay. A launch here could be just a few weeks away.

What will it mean for U.S. jewelry makers? McCreight and Mitsubishi held a five-day workshop in late spring at Haystack Mountain School in Deer Isle, Maine to explore the clay’s potential. There, a group of 15 goldsmiths put the new material through its paces, keeping the oven fires burning on some nights until 3 a.m. They discovered there was plenty the clay could do that conventional forms of precious metal can’t.

For one thing, it turns a tricky operation like stone setting into child’s play. According to Patricia Daunis, Portland, Maine, one of the designers at the workshop, stones (assuming they are of a type that can withstand the heat of the oven) can be set simply by pushing them into the clay. When the material is fired it shrinks around the stone (30% to 40% shrinkage is about average, she says), holding it in place.

Another plus: the clay allows designers to produce effects not possible with casting or stamping. For example, enamel can be dispersed through the material, either uniformly -or in swirls, creating unusual colors. One pioneering craftsman in Britain pushed the clay through a tea strainer, achieving a look that would have been tough, if not impossible, to get any other way. McCreight, after loosening up the clay by mixing it with water, extruded it through a baker’s tube (the type used for decorating cakes) with a star-shaped aperture and got what he described as a “rod with fins” which he looped and swirled into decorative patterns.

PMC also lends itself well to “slip casting,” in which a plaster mold is filled with clay watered down to the consistency of yogurt, then immediately emptied. A layer of clay sticks to the walls of the mold. It is removed, then fired, creating a finely detailed shape (one demonstration McCreight witnessed yielded a little Buddha).

McCreight points out that the 24k version of the metal is much harder than conventional 24k gold. A thin 24k-gold PMC ring he made for his wife is as rigid as a sterling silver one would be, he says.

But its biggest benefits, he believes, are simplicity and speed. Casting requires several steps, clay jewelry just two: shape and bake.

PMC isn’t, of course, perfect. Because of the metal’s porosity, soldering pieces together requires a deft touch. Nor is the clay ideal for high-stress applications like flatware, McCreight says. Its tensile strength is 60% that of conventional gold.

Pros and cons aside, the success of the clay in the U.S. market, McCreight concedes, depends on its price, and that has yet to be determined. “It’s all about dollars, especially when something is new and experimental,” he says.

Modern Jlr, November 1995

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