Ceramic cones play a vital role in monitoring kiln temperatures during firing. These slender pyrometric cones precisely deform at specific temperatures, providing a visual cue that firing milestones have been reached.
Understanding how to use cones ensures your clay and glazes fire as intended. Let's explore cones in depth:
Ceramic cones are tiny pyramids composed of precision-engineered clay and minerals calculated to melt at exact temperatures. Major cone variants include:
Available cone numbers range from 022 to 20, with lower cone numbers denoting lower melting temperatures. The cone number refers to the temperature at which the cone's tip will bend and touch the base.
As cones are heated in kilns, they act as mini clay vessels that distort and bend when their formulated melting point is reached. The tipping action provides a clear visual signal that the clay and glazes have reached the proper maturation temperature.
For example, a Cone 6 Orton cone will bend when the kiln temperature exceeds 2165°F, indicating the clay body and glazes have achieved proper vitrification at that heat level.
Strategically placing a series of staggered cones spanning the target temperature range within a kiln allows monitoring of the firing progress:
Cone packs are arranged with gaps between numbers so the bending sequence is easily read. Placing cones in multiple locations checks for even heating.
Reference cone charts to select appropriate cones for your clay type, glazes, and desired firing methods. Standard cones for common firings:
With practice reading cone behavior, you will master precise kiln firings every time. Let cones take the guesswork out of firing!