Ceramics

Underglaze fires matte and is not sealed unless a clear glaze is applied and fired on top of it. Additionally, underglaze can be similar to a paint in that the fired color is similar to the color when fired. Glazes will melt and seal the piece without the use of a clear glaze and often fire to a very different color than when applied.

Bisque is the initial firing of ceramic pieces to burn off any excess organic matter prior to glaze firing. It also helps strengthen the ware to be handled more often for glazing. We recommend bisque firing to Cone 05/04 when using our underglazes or glazes to ensure best results.

Cones are made of specific materials designed to melt at certain temperatures to indicate heatwork, which is the combined effect of time and temperature. By measuring firing temperature in cones, it ensures a consistent result across variables like kiln or clay type, as well as Fahrenheit or Celsisus.

Cones with a 0 in front of them are a cooler temperature than those without a 0. A great way to visualize Cone temperatures is like a number line, with the 0 acting as a negative symbol. This helps show that Cone 05 is much cooler than Cone 5, as -5 is much less than 5.

Both are certifications recieved from the Art and Creative Materials Institute as a result of extensive toxicological testing. AP is for products that contain no materials in sufficient quantities to be toxic or injurious to humans, including children, or to cause acute or chronic health problems. CL is for products that are labeled in accordance with the chronic hazard labeling standard and are certified to be not hazardous if used in accordance with directions on packaging.