© 2009 Anja Penger-Onyett

All my pots are biscuit fired to cone 06.

After glazing my pots are fired in a gas kiln. The picture on the right shows the flame in the firing chamber at the beginning of the firing.

Firing takes ~9 hours. When the temperature has reached 800-900 Degrees Celsius the damper on top of the flue is slightly closed. This reduces the flow of oxygen going into the kiln, resulting in a reduction atmosphere. The flame is starved of oxygen to the extent that oxygen is taken out of the oxides which are responsible for colouring ceramic glazes. As an example copper, usually green is turned into red, resulting in deep red oxblood glazes.

At this time the flame comes out of every opening of the kiln, for example the spy holes and the flue exit. The trick from here on is to maintain the reducing atmosphere and still achieve an increase in temperature! A bit of a balancing act!

Firing continues in the reducing atmosphere until ~1280 Degrees Celsius.  As additional control for the temperature, or better the “heatwork” which the pots have been exposed to Orton cones had been placed just behind the spy holes. When cone 10 is bend the firing is complete. The kiln has to cool down for at least 48 hours.