PMC Sterling
PMC Sterling combines microscopic particles of metals in the proportions of 92.5% silver and 7.5% copper- which are the same proportions as traditional sterling silver.
The metal powders are mixed with water and a non-toxic binder to create a material that can be worked as easily as modelling clay or other types of Precious Metal Clay.
Work and shape the clay in the same way you would any other type of Precious Metal Clay.
PMC Sterling has a shrink rate of 15%-20%. Firing Due to the copper content PMC Sterling requires a unique, 2-step, firing process. You will need a temperature controlled kiln such as an Evenheat or Paragon kiln, a steel firing pan with lid and activated carbon granules. PMC Sterling cannot be torch fired.
1. This step is to remove the binder. Place the item on a kiln shelf and fire at 540˚C for 30 minutes. After this initial firing process, handle the piece WITH EXTREME CARE as the binder will have burnt off but the piece will not be in a finished solid state yet. Allow your work to cool. Do not quench.
2. Put a layer of activated carbon in the bottom of the steel pan measuring 10 mm deep. Then place your piece on top of the carbon layer. Sprinkle more activated carbon on top of the PMC Sterling piece to create a top layer of at least 10 mm. It is possible to fire multiple pieces in multiple layers but do not put more than three layers in the kiln at any one time and be sure to put a layer of 10 mm of carbon between pieces.
3. Cover the pan using the pan lid and place in the kiln. Fire at 820˚C for 90 minutes.
4. Allow the pieces to cool buried in the carbon. This may take several hours. This will leave the pieces a clean white colour when removed from the carbon.
PMC Sterling can be soldered with any silver solder grade. It can also be enamelled and plated. You may set stones as required providing they can withstand high temperatures for sustained periods.
The melting point of PMC Sterling after firing is 893˚C or 1640˚F
