Wood Fired Stoneware: The kiln is fired with wood over a thirty six hour period, reaching a temperature of 2300 to 2400 degrees Fahrenheit. The patterns that you see on the external surface result from the movement of flame across the piece during firing. As the kiln reaches its maximum temperature, there can be deposits of wood ash. In soda firing, a mixture of baking soda and sodium carbonate suspended in liquid is sprayed at pottery during the firing process. This creates unique effects on finished pieces. The inside of the pieces can be glazed and waterproofed after cooling. A wood firing requires a large number of potters to participate. As many as five hundred pieces may be fired at once depending on the size of the kiln.