Each ceramic glaze should be fired to a specific temperature range. If fired at too low a temperature, the glaze will not mature. If the temperature goes too high, the glaze will become too melted and run off the surface of the pottery. For success, a potter must know the correct temperature range at which their glaze becomes mature.
When potters talk about ceramic firing ranges, they are usually referring to the three most common: low-fire, mid-range, and high-fire ranges. In regards to glazes, we need to add two other ranges: very low-fire and lower mid-range firing ranges.
1. Very Low-Fire Range
- from cone 022 (approx. 1112⁰F – 605⁰C)
- to cone 013 (approx. 1566⁰F – 850⁰C)
This range is usually used for luster glazes and very low-firing overglazes. Ware must be fired at least once at a higher temperature first, in order for the clay body to mature. The ware will often not only go through a bisque firing, but also a higher temperature glaze firing. Very low-fired overglazes and lusters are then applied to the already fired primary glaze. The ware is returned to the kiln for a very low temperature firing in order to fuse the overglazes.