|PMC STERLING Clay can be combined with PMC3 at a ratio of 1:1 to create a Single Fire Sterling Silver.
Ideal for rings, PMC Sterling has a longer working time than other PMC clays and can be hallmarked as 0.925 Sterling Silver.
PMC™ Sterling requires special firing because of the copper content of the alloy. For proper firing you will need a controllable kiln, a steel firing container, and granules of activated carbon.
STEP ONE (firing)
When the work is completely dry, heat to 538°C for 30 minutes, more for thick pieces. After firing, very thin pieces will be fragile.
STEP TWO (firing)
Allow the work to cool so it can be safely handled, then transfer it to a firing container that has a 10mm layer of activated carbon. Set the pieces at least 10mm apart. Sprinkle more activated carbon over the pieces, again creating a layer about 10mm deep. It is possible to fire multiple pieces in layers, but do not make more than three layers, and provide at least 10mm carbon in between each layer.
Cover with a lid, heat to 815°C, and hold for at least 30 minutes. When firing more than three or four pieces, or when the work is more than 3mm thick, extend the firing time to an hour or longer. Allow the work to cool while buried in the carbon. Not only will this prevent burns, but it leaves the PMC™ Sterling a clean white colour. Ventilation is recommended during firing.
PMC™ Sterling can be filed, sanded, tumbled, and polished using traditional jewellery techniques. Filings and scraps can be sent for refining just like other precious metals. Use liver of sulphur or a proprietary oxidizer to develop a dark patina. Because PMC™ Sterling is the result of sintered powders; it does not create fire scale.
PMC STERLING product information insert