THE WOODFIRING PROCESS
Woodfiring is a process in which the kilns that fire ceramic work are fueled by wood, hence 'woodfired'. This method of firing predates other firing methods that came about during the industrial revolution. Many potters choose to woodfire because the use of wood as a fuel source effects the wares in a way that cannot be reproduced in any other type of firing. Each type of tree offers something different as a fuel source. Additionally, different types of tree can create different effects on the wares. These effects can be regionally specific, as trees will absorb different minerals in different locations.
At Cobb Mountain Arts & Ecology Project, we focus on ecologically sound methods of sourcing wood for our kilns. Across the west coast and the Rocky Mountains there are currently epidemics of insects which are killing off ponderosa pines and other trees. We try to source our wood from these beetle kill trees, and focus on maintaining our land in a manner that allows the trees to grow while preventing fire risks. Throughout our winter months we clear undergrowth and thin new growth to allow for healthy growth of existing trees. Due to the recent droughts on the west coast, we have also found ourselves helping clear and collect trees that have died in wildfires and use them as fuel source.
We will collect wood throughout the year and store it for our firing season (October through May). Once we have made enough work to fill a kiln, each piece is wadded with a clay that is resistant to the atmosphere and will prevent it from sticking to the shelves in the kiln. After all the work is loaded and the doors bricked up, we start preheating the kiln. We start a fire just outside of the firebox and over multiple hours, usually overnight, we slowly work the fire into the kiln. This preheat helps to slowly warm the work. If the work is heated too quickly it can crack or explode. Once the preheat is complete, larger pieces of wood are put into the kiln at a gradually faster rate as the temperature in the kiln rises. Woodfirings can be to any temperature, for any range or type of clay. Firings can also last anywhere from twenty four hours to weeks long depending on the size of the kiln or the desired effect. Three to five days or more after the firing is completed, the kiln is cool enough to unload. At this point the doors are un-bricked and the work can be removed. The fireboxes are cleaned of any remaining ash or coals. Shelving is removed, cleaned, and prepped for the next firing.