The ability of a fired clay to absorb water. Used as a gauge of vitrification.

In clay and glaze chemistry, the glass-formers, which combine with bases (fluxes) and neutrals (refractory's or stabilizers).

A wood-extract product used as a clay additive to give greater plasticity, increase dry strength, and improve workability. Especially effective in bodies with a high percentage of kaolins. Does not change color of clay.

Wares featuring swirling marbleized colors, resulting either from surface slip effects or marbleized colored clays.

Industrial method used in processing of raw clays, where powdered clay is floated in an airstream to settle out heavier particles.

Cast able refractory or mortar, which becomes hard and strong while still damp as a result chemical interaction with water.

Adjustable shutter on the rear opening of an atmospheric burner, or on the blower intake of a power burner, used to regulate entrainment of primary air.

Traditional dark brown slip clay used as liner-glaze in high-fired Early American wares. No longer being mined use Alberta slip.

Substitute for Albany slip. Highly fluxed with iron true slip clay will form glaze at HT.

Basic, opposite of acidic chemical nature of many fluxes.

A category of high-fire fluxes, which includes calcium, magnesium, barium, and strontium. Encourage hard, durable, but often matt glaze surfaces.

In low-fire, boron fluxes. In high-fire, the feldspars.

Al(OH)₃ alumina source, rarely used in clay bodies or glazes, because all needed alumina comes from clay and feldspar. Used primarily for shelf wash and wadding ”better adhesion and suspension than aluminum oxide (Al₂O₃). Small additions increase viscosity of glaze melt. Should not be used as matting agent in functional glazes produces immature glaze.

Broad category of materials composed primarily of alumina and silica. Includes raw materials such as clay and feldspar, as well as fired clay and glaze.

Materials such as glass, which have no regular repeating crystalline structure.

Translates "cellar kiln Traditional Japanese kiln evolving from the bank-kiln, and featuring a long, swelling inclined tubular ware chamber, with lower extreme serving as firebox. Characteristically produces heavy flame-flashing and residual-ash effects.

The process of cooling a heated object gradually to allow internal shrinkage stress to equalize without damage.

Sb₃O₃ colorant soluble, toxic, expensive, produces yellow with titanium. Highly toxic in absorption, ingestion, and inhalation.

Bricks with angled side faces, tapering across the width of the brick, which when laid together form a curved arch. Standard arch bricks give 4 1/2" thick arch.

Heavy deposition of fly-ash onto surface of wares, furniture, and kiln interior in a wood kiln.

A gas burner that utilizes the effect of gas escaping from the orifice to entrain primary air, without the need for a mechanical blower.

Constant motion in atoms and molecules, present in all materials. Heat accelerates atomic vibration, eventually breaking atomic bonds, causing transition from solid to liquid to gas.

A glaze featuring iridescent metallic flecks as a result of iron crystals just beneath the surface.

Well-known flashing slips for wood fire, but no longer being mined.