Soda firing, along with salt firing and wood firing, is known as “atmospheric firing”, because the atmosphere inside the kiln contributes directly to the surface appearance of the work. As with wood fire, the clay bodies, glazes and slips are carefully chosen for the way they react chemically to the firing method. It is all about achieving beautiful surfaces! Due to the high temperature firing, soda fired work is highly functional and is microwave, oven, refrigerator and even freezer-safe. It can be washed in the dishwasher, but I always hand wash my prized pieces.
Soda firing typically takes place in a gas fired hard brick kiln over approximately a 12 hour period. Temperatures reach about 2350 degrees Fahrenheit. At about 2300 degrees, a saturated solution of soda, in the form of bicarbonate of soda or soda ash, is sprayed into the kiln through various ports. The kiln is designed and stacked to encourage turbulent flow, but the atmosphere is never completely homogenous. At these high temperatures, the soda combines with minerals in the clay and glazes, giving them a special depth and beauty.
Enjoy! Beverly Curtis