Making the Glaze:

• 900g Copper Oxide

• 90g High Alkaline Frit

• 20g Bentonite

• Water

Method:

Combine the ingredients above and create a watery wash, not thick like shop bought glazes. It should be the consistency of milk, not cream.

Dip the pot in the wash, or brush on. Dipping is better as it doesn't leave brush strokes. The glaze should be whisked just prior to dipping as the glaze settles very quickly.

When dry you should put it in the Raku kiln and fire to 1030 Degrees Celsius at a steady rate- it normally takes about 40 minutes to reach temperature.

When at 1030C turn the kiln off and close off all holes but leave the pot in the kiln to cool. Closing off the kiln vents restricts the oxygen in the kiln and is necessary to get the oxide to react.

When the kiln has cooled to 800C remove the pot and place on a bed of shredded paper and allow the heat of the pot to set fire to the paper. Keep the flames burning around the pot for 30 seconds (watch the colour change!) and then cover the pot completely with a tin to cut off all the oxygen within the tin.

Leave for 2 minutes and then lift the tin very quickly (as fast as you can), to allow a small amount of Oxygen to get to the oxide wash on the pot. In this 1 second you will see the colours change rapidly across the surface of the pot.

Replace the tin and leave for 45 minutes to cool.

After 45 minutes remove the tin and the pot is finished.

Tip - place the shredded paper onto a hardibacker board (concrete board), and place some fine sand (like aquarium sand) on the board, then place the shredded paper on the sand. When you place the tin over the pot, the sand will restrict the Oxygen and creates a seal which is needed for the chemical reaction to occur.

Credit for the copper matte recipe goes to Lesley at The Pottery Wheel who was really helpful and generous with her knowledge so check her site out here