The fraction of any material that volatizes and outgases during firing includes carbonates, sulfates, nitrates, organic contamination, and chemically combined water.

2(PbCO₃)—Pb(OH)₂ former source of lead for glazes. Highly toxic in absorption, inhalation, and ingestion. Remove from studio and dispose of in a responsible fashion.

Pb₃O₄ Former source of lead for glazes. Highly toxic in absorption, inhalation, and ingestion. Remove from studio and dispose of in a responsible fashion.

3PbO—2SiO₂fritted lead compounds LT flux, but resulting glazes may be toxic and should not be used on functional wares. Most powerful of all fluxes, promotes smooth-flowing, self-healing glazes. Highly toxic in inhalation and ingestion.

Condition of clay where it has stiffened but is still damp. Point at which pieces are joined and most surface modification and trimming are done. Soft leather-hard ideal for forming, joining, thick slip-decorating. Medium leather-hard good for thin slip- decorating, joining, incising, carving, piercing. Hard leather-hard good for thin slip- decorating, carving, scraping.

Lithium feldspar HT alkaline flux used for thermal shock bodies and matching glazes. Contains fluorine, with associated problems. Toxic in inhalation.

CaCO₃ alkaline earth, contributing calcium oxide to glaze powerful AT flux major HT flux for glazes gives strong durable glass. Sometimes used in low-fire clay bodies to extend firing range and give greater fired strength.

A set of formulas giving ideal ranges of glaze oxides that can be present in glaze unity formulas at different firing temperatures. Used in conjunction with glaze calculation to predict or evaluate glaze performance. See unity formulas.

Method for testing glaze materials, where proportional amounts vary through a series of samples between two limits. May involve change in a glaze material, or addition of a colorant or modifier. See triaxial blend.

Li₂CO₃ powerful AT alkaline flux, especially with soda or potash feldspars. Promotes hardness and recrystallization in LT glazes. Forms low-temperature eutectic with silica. Toxic in inhalation.

High-iron (4%) orange-red stoneware clay substitute for Ocmulgee, which is no longer being mined.

The fraction of any material that volatizes and outgases during firing includes carbonates, sulfates, nitrates, organic contamination, and chemically combined water.

Firing range usually including cone 01 to cone 3, underused in studio ceramics, useful for functional earthenware, refractory sculpture bodies, and outdoor terracotta work.

Low-temperature firing range, usually below cone 02 (2048° F), used for most bisque-firing and for glaze-firing terracotta and white ware.

Metallic over glaze finish created either by painting prepared luster (metallic salt in organic binder) over previously fired glaze and firing to cone 018 or by spraying metallic salt dissolved in water into kiln and/or on to wares at low red heat, either during cooling cycle of a glaze-firing, or in a separate firing heated to that temperature.

English word for attaching clay forms with slurry.

Potassium hydroxide or sodium hydroxide. Caustic alkaline soluble that leaches out of wood ashes when they are soaked in water. Occasionally used as a flux additive in terra sigillata, as in the black slip on Classical Greek wares. Toxic in liquid state, and may cause burns.