A Basic How To and History

The technique of salt glazing was discovered sometime in the 14th century in Germany. The process was originally used with low-fire ceramics, but quickly became a favorite technique with stoneware. Western Europeans used the salt glaze process in salt kilns quite extensively during the 16th and 17th centuries.

Americans have produced salt ware since early 1700s in Pennsylvania, Virginia and American Stoneware became the predominant American houseware during the 19th century. Today, North and South Carolina are well known for continuing salt fire production.

Salt firing is one ceramic process that was created outside of Japan and carried to their culture in the early 1900s. This method is one that is continuing to be used for experimentation and creativity in the field of ceramics and pottery. Modern potters and ceramists continue to explore many of the old techniques. One should keep in mind that this method is hard on contemporary electric kilns in that the fumes are corrosive and destructive to the kiln interiors. Most craftsmen opt to use gas kilns, specialty or home made kilns when using various salt methods.

The process is quite simple. Salt fumes have a profound effect on clay when subjected to heat. When temperatures in the kiln reach the melting point of salt at about 1660 degrees F, salt is introduced by using the peepholes or quickly lifting the lid and tossing in some common rock salt. When the temperatures reach as high as 2350 degrees F, salt becomes a vapor in the kiln interior giving off a by-product of hydrochloric acid. This produces a semi-vitreous state with a random surface coloration over the ware.

CAUTION: Salt/fumes can cause corrosion and damage to interior of electric kilns, most specifically the elements.

Salt firing can be done in a one or two firing process. In other words, it can be done with greenware or with bisque ware.

Artists and craftsmen have tried various other methods to create unusual salt ware and pottery. These methods include soaking the bisque ware in a salt brine before firing it or taking ropes or other materials that have been soaked in brine and wrapping the bisque ware with them then firing. Salt, in liquid form, can also be added to colored clay slip or sprinkled on bisque ware in pottery containers called saggars.