Formulating iron rich clay bodies in a recycled electric kiln

Abstract

Clay bodies can be formulated using commonly available processed clays for a wide variety of specific functions. Some of the functions I am interested in include plasticity for throwing on the wheel, temperature range that a clay can be fired to and color for aesthetic purposes. Research into this area by ceramic artists is ongoing. Developments in pyrometers; measuring kiln temperatures, and oxygen probes; that measure the relative atmosphere in a kiln, has improved the knowledge and quality of this research. These tools have allowed artists to critically analyze the chemical processes that affect the iron in clay and replicate results achieved when clay is fired and turned into ceramic material. For consistent results and a fast turn around, I constructed a small gas, 2cu.ft, test kiln out of an old defunct electric kiln. My initial research involved using four different firing methods that cycled between reducing and oxidizing atmospheres on ten formulated high iron clay bodies. I looked for specific color variations in the fired test pieces that resulted from the relationships between the atmosphere and the relative temperature inside the kiln. The clays used in the research undergo vitrification in the firing process and therefore do not need to be glazed to eliminate porosity. This allows the marks made by my hands and tools to be clearly visible in the fired work, which when displayed, or used as a utilitarian object, allows the viewer access into the process of formation and a direct connection back to the maker of the object.