Firing Cones

Orton Firing Cones

Pyrometric cones are used in ceramics to measure how much heat and time the clay or glaze has absorbed during firing. They’re made from special materials that melt or bend at specific temperatures. As the kiln heats up, the cone bends more, showing how much heat-work has occurred. This helps potters know if their kiln has reached the right temperature and held it long enough for proper firing. Different cones bend at different temperatures, so they are numbered to indicate this.