Experiments with silverclay - part 2

Now that my pieces are thoroughly dry, it's time to fire them.

I placed my metal clay piece in the middle of the firing brick. You need a clock nearby for timing the firing and also a glass of water and metal tongs within easy reach. For safety reasons I also recommend wearing goggles. Make sure the place where you fire is well-ventilated - I set up a little station right by the open door to my veranda.

Ignite the torch and hold it at a 45° angle, about 4-5cm from the piece. Keep moving the flame over the piece. You will see a small amount of smoke and flame after a little while (this is the clay binder burning away), and then the piece will turn white. Keep the torch moving over the piece at all times. After a while you see the piece glow. When the piece turns a peachy-salmon color, begin to time the sintering cycle. Holding a sintering temperature (the peachy color) is important as it is sintering which joins the particles of silver together to create a strong and solid mass. Without this your piece will be brittle.

Sintering time ranges from about 2 to 5 minutes, depending on the weight and size of the piece. My pieces are quite small - about 1 cm across and 2 mm thick - so I held this temperature for about 2 and a half minutes. Increase or decrease the distance of the torch from the metal clay piece, depending on whether the color intensifies or fades. If the piece begins to look shiny or if you see sparks, the piece is near the melting point and you DON'T want this to happen. In this case just move the torch further away from the piece.

Immediately after firing, I used my metal tongs (tweezers will also do) to transfer the piece into the glass of water right next to the brick. This is called quenching. You can also move your piece (using a tool of course NOT your hands) to the cooler edge of the firing brick, and allow it to cool completely.

But whatever you do, DO NOT touch the piece until it is fully cooled!

At this point the piece will be white and still look like clay. Brushing and polishing, in the next tutorial, will bring up the lovely silver shine.

Experiments with PMC silver clay - part 1

I finally bought some PMC3 silver clay and started to experiment a few weeks back. PMC3 is supposedly the easiest of the metal clays to fire with a torch, but it is hideously expensive so I was very nervous about using it. Silver metal clay results in objects containing 0.999 pure silver, so has a higher silver content than sterling silver. I prepped myself by watching lots of You Tube videos and reading blog posts by PMC gurus. This is my basic equipment:



1. Acrylic block for rolling out the clay onto, but any non-porous smooth surface will do.
2. Plastic roller for rolling out the clay. Mine has rubber rings to help with rolling out a level thickness of clay, but 4 playing cards on each side of the clay to rest your roller on while rolling will do just as well.
3. Tiny plastic pot with an airtight lid for saving bits of unfired clay or slip. (Slip is ground down unfired clay with a little water added to make a thick paste)
4. Fine files for smoothing the clay in the unfired stage. I bought a pack of 5 quite cheaply for the local hardware store.
5. Brass brush for polishing after firing
6. Agate burnisher for bringing up a shine after firing and brushing. I have read that the back of a teaspoon could be used for this, but haven't tried it myself.

Something else which is necessary is olive oil - I actually used rapeseed and it worked just fine. There are many products available from PMC suppliers, like badger balm, but why bother when most people have something already in their kitchen. It is basically just used to stop the clay sticking to the surface of the tools it comes into contact with. I just put some onto a piece of kitchen roll and lightly rubbed down my equipment - acrylic block, roller, molds etc. Another thing not pictured which is useful is a fine(very fine) artist's paintbrush.

My torch is a simple small butane torch bought on ebay and it will need to be filled with butane gas (lighter fuel) before use.

I shaped my clay by hand into circles about 13mm across and used metal charms and stamps on them. I also made a hole with a needle to be able to put a ring though later. You only have a few minutes to work with the clay before it starts to dry and crack.



I left them to dry for 24hrs on a windowsill over a radiator. I filed the charms to get smooth edges and filled in any small cracks or nicks with slip and a fine paintbrush before firing. To be continued....!