In the production of ceramics, pyrometric cones are clever instruments used to measure heatwork—the combined effect of temperature and time—inside a kiln.

Rather than recording air temperature at a single point, cones respond to the total thermal energy absorbed, closely matching how ceramic bodies and glazes themselves react during firing. When sufficient heatwork is reached, a cone softens and bends, permanently recording the firing conditions.

Cones are manufactured so that each cone number corresponds to a specific heatwork range. For example, low-temperature cones such as #020 are commonly used in glaze testing, enameling, and ceramic materials research, while higher-numbered cones track progressively hotter firings. Their behavior is engineered through precise mixtures of alumina, silica, and fluxes, formulated so molecular rearrangement occurs at predictable energy thresholds.

The gauge on the reverse of this card provides a fixed reference angle for reading cone deformation.

Includes 2 cones (1 pair)
Self-Supporting Cone #020
Color: Orange