Zircon opacifier, no longer being manufactured. Toxic in inhalation.
Source:
Clay: A Studio Handbook
Zirconium Silicate
ZrSiO4—zircon opacifier—inert dispersoid in glaze melt—low-cost substitute for tin oxide—use double the recipe weight of tin. Includes Zircopax, Opax, Superpax, Ultrox. All are toxic in inhalation.
Source:
Clay: A Studio Handbook
Zirconium Oxide
Common opacifier, often used in place of the more expensive tin oxide. Sold as Opax, Superpax, Ultrox, etc., use 7% in a slip and 10 to 12% in a clear glaze to get pure opaque white. Zirconium particles are extremely refractory and remain as inert inclusions in the glaze-melt. They will not affect matteness or gloss, but will increase viscosity.
Source:
Clay: A Studio Handbook
Zinc Oxide
ZnO—High-temperature flux that promotes brilliant glossy surfaces. In some glazes can encourage opacity. With titanium in low-alumina glaze can encourage macrocrystalline growth (crystalline glazes). Volatizes in high-fire reduction. Toxic in inhalation.
Source:
Clay: A Studio Handbook
Yellow Iron Oxide (Yellow Ochre)
High-iron yellow clay mineral, used as colorant in glazes and slips, converts to red iron oxide in oxidation or black iron oxide in reduction and/or high-fire.
Source:
Clay: A Studio Handbook
XX Sagger
A plastic refractory stoneware clay, often used in sculpture and raku bodies.
Source:
Clay: A Studio Handbook
Wollastonite (Calcium Silicate)
CaSiO3—used in partial replacement of silica and whiting in high-temperature bodies, improves thermal shock resistance. In some cases, it is used in place of whiting to eliminate L.O.I. Toxic in inhalation.
Source:
Clay: A Studio Handbook
Whiteware
Low-temperature white clay body.
Source:
Clay: A Studio Handbook
Wheel Wedging
Working the clay up and down in a cone shape on the wheel to align the platelets in a spiral formation and thus increase control in centering and throwing.
Source:
Clay: A Studio Handbook
Wedging
Process of kneading the clay with the hands to remove air bubbles and ensure homogenous mass.
Source:
Clay: A Studio Handbook
Wax Resist
Melted wax or wax emulsion used to prevent slip or glaze from adhering to a clay surface, either in decorating, or in preparing work for glazing.
Source:
Clay: A Studio Handbook
Water Of Plasticity
Amount of water required to bring a dry clay to its state of ideal plasticity. Common clay test used to determine this amount. The more water needed, the finer the particle size, the more plastic the clay, and the greater the drying shrinkage.
Source:
Clay: A Studio Handbook
Waster
European term referring to a fired piece discarded due to damage in firing.
Source:
Clay: A Studio Handbook
Warping
Distortion of clay forms caused by uneven stresses within clay due to forming method, uneven drying, uneven support in firing, or uneven or excessive heat in firing.
Source:
Clay: A Studio Handbook
Vitreous Engobe
An engobe containing sufficient flux to form to a vitreous clay coating.
Source:
Clay: A Studio Handbook
Vermiculite
A porous expanded mica product used as filler in clay bodies and in insulating refractory layer on kiln exterior.
Source:
Clay: A Studio Handbook
Venturi Burner
Natural-draft gas burner featuring streamlined restriction in burner tube, which increases entrainment of primary air and the efficiency of gas-air mixing.
Source:
Clay: A Studio Handbook
Veegum T
Suspension agent/plasticizer similar to bentonite and macaloid. Up to 2% of dry materials weight as plasticizer in high-kaolin clay bodies, and up to 1/2 of 1% of dry-materials weight as suspension agent, brushing medium in glazes and slips. Mix with water before adding other ingredients. Product of H.T. Vanderbilt Company.
Source:
Clay: A Studio Handbook
Veegum Cer
Combination of Veegum T and carboxymethylcellulose gum, used as a suspension and adhesion agent in glazes. Product of H.T. Vanderbilt Company.
Source:
Clay: A Studio Handbook
Vapor Glazing
Any glaze process where the glaze results from vapor deposited within the kiln—includes salt glazing, soda glazing, fuming and wood firing (where fly ash is deposited on the ware and melted into a glaze).
Zircon opacifier, no longer being manufactured. Toxic in inhalation.
Source: Clay: A Studio Handbook
ZrSiO4—zircon opacifier—inert dispersoid in glaze melt—low-cost substitute for tin oxide—use double the recipe weight of tin. Includes Zircopax, Opax, Superpax, Ultrox. All are toxic in inhalation.
Source: Clay: A Studio Handbook
Common opacifier, often used in place of the more expensive tin oxide. Sold as Opax, Superpax, Ultrox, etc., use 7% in a slip and 10 to 12% in a clear glaze to get pure opaque white. Zirconium particles are extremely refractory and remain as inert inclusions in the glaze-melt. They will not affect matteness or gloss, but will increase viscosity.
Source: Clay: A Studio Handbook
ZnO—High-temperature flux that promotes brilliant glossy surfaces. In some glazes can encourage opacity. With titanium in low-alumina glaze can encourage macrocrystalline growth (crystalline glazes). Volatizes in high-fire reduction. Toxic in inhalation.
Source: Clay: A Studio Handbook
High-iron yellow clay mineral, used as colorant in glazes and slips, converts to red iron oxide in oxidation or black iron oxide in reduction and/or high-fire.
Source: Clay: A Studio Handbook
Source: Clay: A Studio Handbook
CaSiO3—used in partial replacement of silica and whiting in high-temperature bodies, improves thermal shock resistance. In some cases, it is used in place of whiting to eliminate L.O.I. Toxic in inhalation.
Source: Clay: A Studio Handbook
Low-temperature white clay body.
Source: Clay: A Studio Handbook
Working the clay up and down in a cone shape on the wheel to align the platelets in a spiral formation and thus increase control in centering and throwing.
Source: Clay: A Studio Handbook
Process of kneading the clay with the hands to remove air bubbles and ensure homogenous mass.
Source: Clay: A Studio Handbook
Melted wax or wax emulsion used to prevent slip or glaze from adhering to a clay surface, either in decorating, or in preparing work for glazing.
Source: Clay: A Studio Handbook
Amount of water required to bring a dry clay to its state of ideal plasticity. Common clay test used to determine this amount. The more water needed, the finer the particle size, the more plastic the clay, and the greater the drying shrinkage.
Source: Clay: A Studio Handbook
European term referring to a fired piece discarded due to damage in firing.
Source: Clay: A Studio Handbook
Distortion of clay forms caused by uneven stresses within clay due to forming method, uneven drying, uneven support in firing, or uneven or excessive heat in firing.
Source: Clay: A Studio Handbook
An engobe containing sufficient flux to form to a vitreous clay coating.
Source: Clay: A Studio Handbook
A porous expanded mica product used as filler in clay bodies and in insulating refractory layer on kiln exterior.
Source: Clay: A Studio Handbook
Natural-draft gas burner featuring streamlined restriction in burner tube, which increases entrainment of primary air and the efficiency of gas-air mixing.
Source: Clay: A Studio Handbook
Suspension agent/plasticizer similar to bentonite and macaloid. Up to 2% of dry materials weight as plasticizer in high-kaolin clay bodies, and up to 1/2 of 1% of dry-materials weight as suspension agent, brushing medium in glazes and slips. Mix with water before adding other ingredients. Product of H.T. Vanderbilt Company.
Source: Clay: A Studio Handbook
Combination of Veegum T and carboxymethylcellulose gum, used as a suspension and adhesion agent in glazes. Product of H.T. Vanderbilt Company.
Source: Clay: A Studio Handbook
Any glaze process where the glaze results from vapor deposited within the kiln—includes salt glazing, soda glazing, fuming and wood firing (where fly ash is deposited on the ware and melted into a glaze).
Source: Clay: A Studio Handbook