Description
Orton manufactures four different types of cones (Small cones, Bar cones, Large cones and Self- supporting cones).
The Large and Self-supporting cones are used to measure temperature uniformity and/or if there was sufficient heatwork done to mature the ware. Cones indicate whether the ware received an adequate amount of heatwork to properly mature the clay or glaze. A properly fired cone will bend over with the tip of the cone almost touching the shelf. After firing a kiln, a simple glance at the cone can tell if the firing was successful.
The small and bar cones are mainly used in the kiln shut-off device called the Kilnsitter. This ia mechanical device that shuts off the kiln when the temperature inside is sufficient to cause the cone to deform under the weight of the Kilnsitter rod.
The only true measurement of heatwork is from a Large or Self- supporting cone placed on the shelf next to the ware.
Frequently Asked Questions about cones can be found on Orton website.
Resources may also be found on the Orton website
Small Cones
Small Cones are commonly used in the Kiln-Sitter®. The tapered shape allows some flexibility to adjust shut-off by placing the thinner or thicker portion of the cone under the sensing rod.
Small Cones can also be used on the kiln shelf as miniature witness cones when space is limited. They require mounting in cone holders or plaques at an 8° angle and a width of 15/16 of the cone exposed above the cone holder. Small Cones used on the kiln shelf deform at about 9°F after Large or Self-Supporting Cones of the same number.
Cone numbers 12 and higher are also available as PCE cones.
In 2016, Orton began packaging Small cones in pairs like Large and Self-Supporting cones. We made the change to reduce the number of cones broken during shipping.
