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  • Writer's pictureKatherine Fortnum

Kiln Firing Method - Gas Firing

Firing clay is the most critical part of the ceramics process because it is the one thing that makes clay durable, hence ceramic.

Gas reduction firing uses a fuel, such as natural gas or propane. The temperatures of a gas fired reduction kiln may exceed 2300F, when the glazes melt and mature. Because gas is a combustible fuel, the potter can control the ratio of oxygen to gas during the firing.

Depriving the kiln of oxygen creates an atmosphere known as reduction, where carbon monoxide can be produced. By reducing the oxygen during this refractory process, the glaze colours will change and become enhanced. This can only occur in fuel fired kilns.

It is the burning of chemically combined oxygen in the clay and glaze minerals that gives reduction fired pottery its unique characteristics. The reduction cycle is responsible for a wonderful and unique palette of colours which occur when oxygen deprived molecules seeks the chemically bound oxygen from minerals that are in clay and glazes.

Various glaze colours can be achieved in a reduction firing, Red is very hard to achieve with many ceramic materials and firing methods but in reduction a wide range of reds can be achieved. Many glazes are enhanced by reduction firing, but copper red glazes are some of the most dramatic.

Gas Fired Kilns may not produce pottery with the even and consistent results of electric kilns, however reduction firings can yield subtle hues in the colour of the clay body, and variations in the glazes, which make each pot unique.

inside a gas kiln

An example of a gas fired ceramic piece



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