Firing Down

So far in my ceramic education and experience I have consistently fired my work at cone 10 (high fire) which is the highest/hottest temperature to fire at, reaching roughly 2300-2400 Fahrenheit. The difference in cone temperatures creates differences in the end product that comes out of the kiln. There are specific clay bodies and specific glazes or stains to be used for each temperature range, and the chemistry of what happens in the kiln differs at each stage.

This semester as I work in Italy, I have been using cone 6 earthenware clay and glazes, which means the temperature of the kilns only reaches about 2100 Fahrenheit. Because the temperature is lower, the clay and glazes do not ‘do’ as much as higher cone temperatures. By this I mean that the clay remains slightly more porous in bisque firing, and the glazes do not mix as much in glaze firing.

Many people enjoy the beautiful mixtures of high temperature glazes (examples shown above). You can see the movement of the glazes in reaction with each other during firing, they mix, and melt into beautiful combinations. These effects are more difficult or impossible to get at lower temperatures; but there is something to be said for the consistent and predictable nature of glazes at cone 6. Because there is less mixing and moving of the glazes at cone 6, you can be almost certain of the results you will achieve after practicing with your glaze combinations.

This piece was fired at cone 6, using a stain applied to the bisque-ware, and a transparent glaze sprayed over top that. You can see the stain showing through in the textured ribs where the green is.

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