The tutor was Sima Vaziry. Sima started by explaining what metal clay is and then talked us through three different projects. Metal clay originated in Japan. It is a clay that contains small particles of metal and a binder. It can be moulded into shapes and once dry can be fired using a blow torch, kiln or on a stove. After firing the white binder is brushed away to reveal pure metal, which is 99.9% pure silver! You can also buy gold and bronze metal clay.
The first project we worked on was a pair of earrings. As a test, we used some Fimo (polymer clay) to work out what we we wanted the finished design to look like. We used a texture sheet, like the ones shown here. On top of the texture sheet you need to put a pile of four playing cards on either side. Make sure you grease your hands with Badger Balm (not made from badgers!) or olive oil, and everything the clay will come into contact with as this stops it sticking to your clay. Roll the metal clay into a ball and place it onto the texture sheet, then use a roller to roll it out to the thickness of the playing cards. Use a cutter to cut out the shape you want. For my earrings I used two heart cutters - a large one and then a smaller one inside. I also created a small hole for the earring findings to go through.
Spray water on your left over clay and wrap it inside some oiled cling film to keep it moist. Metal clay dries out quickly so you need to do this to ensure you can use what you have left.
Once I'd created my heart shapes in the clay, I sanded the edges until I was happy with them and then they went into a special drying machine to speed up the drying process. I'm not sure what this was called but at home you can leave it for 24 hours a room temperature or you can use a hairdryer or hot plate to speed up the drying process. The pieces turn white once they are dry and you need to ensure they have no moisture in them. You can test this by putting the piece into the lid of the Badger Balm and seeing if any condensation occurs when you move it from side to side. If there is no condensation then the piece is ready for firing. If the piece breaks, you can use metal clay paste to stick it back together, but you then need to dry this out again.
To fire the clay pieces we put them on a block and used a blow torch (whilst wearing safety googles!). When you heat the piece using the blow torch you will see a flame as if it has set on fire, then it will turn black and then white again. Once it turns orange you should time it for 2minutes 30 seconds while you move the blow torch over it. Be careful not to have the torch too close. If the piece starts to glow bright orange then it is melting and the torch is too close. Metal clay does shrink a little when it's fired so you need to take this into account when you are making things. Once the time is up carefully place the pieces into a bowl of cold water using tweezers. They will then be cold enough to handle.
The next stage is when the magic happens. The pieces are still white, but once you brush them with a brass brush they become silver! After this you can polish them using polishing paper and finally with a burnishing tool, which makes them very shiny.
Here are the heart earrings I made. You can see the bumpy texture created from the texture sheet:
After making these, I used the same technique to make this flower pendant, but attached a circular piece of clay on top, using metal clay paste, to ensure a thick enough part for a stone to be set into. I pressed the stone into the clay until the top surface was in line with the surface of the clay. If you don't set it in far enough it can shoot out at you when firing the clay. Only stones suitable for firing can be used as non heat resistant stones will just turn orange or black. Also, if your piece has a stone in it you can't put it into cold water after firing. You need to leave it somewhere for about 15 minutes until it has cooled.
The flower pendant I made was dipped in Liver of Sulpher mixed with warm water and rinsed with clear water to give it an antique effect. This process is called adding a patina. If you don't like the patina you can burn it off with a torch.
For the last part of the day we made our own moulds using a two part silicone moulding compound like the product shown here. You just need to roll a small amount of each part into a ball and knead them together until they are blue. Then you can stretch them over an object of your choice and leave it to harden. You can then use the mould to create a piece from metal clay. I created this teapot mould and the silver teapot charm below:
