As is well known, a crucial step in ceramic pottery is firing the pieces in a kiln. In addition to knowing how to choose a kiln that suits your style and work, you must also understand the appropriate temperature for ceramic work, and of course, a crucial aid like a thermometer is essential.
Today, Pottery Clay invites everyone to learn about the "Pyrometric Cone" type of temperature measuring tool, another helpful device that ensures excellent pottery work.
'Pyrometric cones' are small pyramids, composed of three triangular sides, slightly slanted, about 1 ¾ -2 inches tall, with a base about ½ inch wide. They are made from a mixture of clay and glazing materials and are set in soft clay in a row. When the specified temperature is reached, the cone bends over as an indicator.
Cones are inventions that use a variety of materials mixed together and melted at specific heats, from cone 022 (675 degrees Celsius) to cone 42 (2,093 degrees Celsius). Each cone has a number marked on its base, and the average temperature difference between each cone is approximately 17.5 degrees Celsius.
For low-fire cones, numbering starts from 0 up to a number. The dividing point between cone 01 and cone 1 is at 1,093 degrees Celsius, which is the melting point of iron. Cone numbers and temperatures to remember are those commonly used for bisque and glaze firing, such as cone 08 at 955 degrees Celsius, cone 9 at 1,280 degrees Celsius, and so on.
Furthermore, pyrometric cones also measure refractories. When using a pyrometric cone, which is a tall, triangular ceramic object with a base wider than its top, it begins to bend over when fired to a certain temperature. There are two types of pyrometric cones in use: Seger Cone and Orton Cone. The Seger Cone was first made by a German scientist and then widely adopted in the ceramic industry due to its accuracy and ease of use. Later, it was named Seger Cone in honor of Prof. Dr. Seger Kegel, with the letters SK becoming the symbol or brand of the cone. The Orton Cone is the same type as the Seger Cone but is used in the United States.