About Wood-Firing

On the pieces fired in Joy Brown's wood-fired kiln in E. Kent, Connecticut, ashes from the wood fuel have settle on the ware and fused to produce a varied surface. The dark brown color is from iron in the clay. Wood-fired ware, as fired in Joy Brown's traditional style tunnel kiln, is the result of an arduous and risky process of firing over a week-long period. The kiln is fired solely by wood, and gradually builds in temperature to about cone 8-9 (2250 F) in the front, to cone 2 (1600 F) in the back. The front of the kiln produces ware that is heavily encrusted with ash, some of which melts and flows, some of which remains crusty and rough. Ware in the middle sections of the kiln has less ash, and a softer look. Toward the back, the colors are lighter. There are more oranges and grays and fewer dark brown as the clays are not vitrified so thoroughly as in the front section. Ash deposits can be dark gray. This section is reserved for sculpture and tiles.

The firing begins slowly, and continues day and night for a week or more. The firing crews work in 12 hour shifts, replenishing the wood, feeding it into the kiln's mouth every ten minutes or so. After several days, the temperature reaches red hot, and continues from there to become a roaring inferno by the seventh day. After firing, the kiln must cool for a week before the front bricks and side door bricks are taken out and the ware is removed. Piles of ash are shoveled out of the kiln. Heavy shelves are removed and stored for the next firing. The fired ware is then carefully removed from the kiln and assessed. Ash residue that has not melted is washed off. Very rough surfaces may be sanded or smoothed with a stone. Notice is taken of how well the ash has interacted with different clays, how various shapes have withstood the firing, and whether the patterns of ash and flame have indeed enhanced the forms, or as sometimes happens, simply created an ugly mess. There are many unpredictables in wood-firing including the weather, the age and dampness or dryness of the wood, the type of wood, the size and shape of the wood, the amount of time allowed between stokes, the amount of draft and oxygen in the kiln during the firing, the density of the stacking of ware within the kiln and more.