YOU ARE HERE: Home > Learning Center > What is metal clay? > PMC Silver Alloy Clay Products

PMC Silver Clay Products

Silver Alloy Clay Products

These clays offer the user the strongest final product, comparable to sterling silver. When fired, they are nearly indistinguishable from a cast object.

The Basic Form: Lump
Lump Form

The basic clay material is called "lump form". It comes in a sealed foil packet and is ready to use. Lump form is used to roll slabs, snakes and to mold or sculpt objects. Lump form can be thinned with water and used as a paste. EZ960 and PMC Sterling come in lump form only.

PMC Silver Alloy Product Line


This clay is an alloy consisting of 96% silver and 4% copper, and is the only sterling alloy on the market that is kiln fired on an open shelf, with no carbon required. EZ960 is a great, all purpose metal clay with excellent working properties. Because the clay is a sterling silver alloy, one of its best attributes is its post firing strength, in comparison to fine silver. This clay has a relatively low shrinkage rate at 10 - 11%.

Uses The inherent strength of EZ960 makes it the perfect choice for jewelry that takes lots of abuse, such as rings and bracelets. It is also great for jewelry with findings and components such as bails, hinges and clasps, as well as delicate pieces that would benefit from the strength of sterling silver.
Workability Ready to use directly from the package, the first thing you will notice is its smooth, creamy consistency. The clay accepts and telegraphs the smallest of details in textures very well. It is easy to roll and form, and is surprisingly non-sticky. It also has a high moisture content, making it easy to work with in its wet form, as it stays workable and pliable without drying and cracking when forming, texturizing or molding. For best long term storage and to maintain hydration and workability, store unused EZ960 in a metal clay hydrator charged with distilled water.
Cubic zirconia, lab created gemstones, bezel cups and other findings or embeddables can be co-fired with EZ960. Please refer to our Gemstone Firing Guide for a comprehensive list of gemstones that are compatible with the firing times and temperatures of EZ960. Most, but not all czs and lab created gemstones can be fired at 1675F/913C for 2 hours on an open kiln shelf (see Firing Schedule below) without failure or color change.
After ensuring the clay is bone-dry, kiln fire on an open shelf at full ramp speed at any of the times and temperatures below:
Kiln Temperature & Hold Time:
1675F/913C - 2 hours
1700F/927C - 1 hour
1725F/941C - 15 minutes
For low temperature kilns:
1650F/899C - 4 hours
1625F/885C - 4hours
1600F/871C - 8 hours
Torch: Not recommended

To prevent "sticking" on the kiln shelf, line the shelf with ceramic fiber paper (kiln paper) or, create a thin coating of crushed vermiculite on your kiln shelf. For objects that require special support: Vermiculite, pumice or alumina hydrate in a kiln safe container works well. We do not recommend fiber blanket, as it may stick to EZ960 during firing.

Items directly from the kiln will be slightly grayish in appearance, and is normal for an alloy of this type.

Lump Form - PMC Sterling
PMC Sterling

This Precious Metal Clay comes out of the kiln as solid sterling silver. It is ideal for thinner, more delicate designs such as rings, findings and components which need the added strength of a silver alloy such as PMC Sterling. This alloy product is 92.5% fine silver and 7.25 copper. This clay has a shrinkage rate of 15 - 20%.

Uses Create stronger jewelry, findings and components with this clay. Perfect for rings. Due to its alloy strength, use less clay and make components thinner and stronger. Quality mark with .925 hallmarking.
Workability Workability is excellent with a smooth feel to the clay. If texturing the clay with a rubber texture, we recommend conditioning the clay with slik, which will allow for a clean release of a texture. It is noticeably stronger even in the wet stage allowing it to be shaped and molded into smaller and more intricate lightweight pieces, ultimately using less clay. After tumbling for work hardening, the polish is beautiful and the final product is .925 sterling.
Please review our Gemstone Firing Guide for information on which gemstones can tolerate a co-firing with PMC Sterling. Generally, any gemstone that can withstand kiln temperatures of 1500F/816C for 30 minutes can be embedded successfully with this clay.
PMC Sterling is fired in a two stage process.
1. Fire for 30 minutes at 1000F/538C in open air on a kiln shelf to burn away the organic binders. Let cool.
2. Place in carbon in a stainless steel firing container. For best results, ensure 1/2" of carbon surrounds your article on all sides. Several pieces can be stacked, and fired together, if you maintain the 1/2" carbon between and around your pieces. Fire, at full ramp speed, at 1500F/816C for 30 minutes. For thicker, larger pieces, fire for one hour to ensure complete sintering, strength and durabilty.