Glossary Terms (Simple)

Stoneware

High-fired vitreous ware, literally as hard and durable as stone. Matures from 2200-2400° F. (cone 5–11).

Source: Clay: A Studio Handbook

Sprung Arch

Kiln arch representing less than 180 degrees of curvature, and requiring buttressing to support outward thrust of the arch. 

Source: Clay: A Studio Handbook

Sprigging Ceramics

Surface decorating technique in which small coils or balls of clay are affixed to the damp or leather-hard surface, usually with a layer of slip.  

Source: Clay: A Studio Handbook

Spraying

Application of liquid slip, engobe, glaze, or stain, using mechanized spray equipment. Gives smooth glaze coating, but with less glaze pooling in recesses. 

Source: Clay: A Studio Handbook

Spray Booth

Open-front enclosure with an exhaust fan at the rear, designed to draw off all overspray and other toxic dust or fumes. 

Source: Clay: A Studio Handbook

Spodumene

Li2O×Al2O3×4SiO2—lithium feldspar—powerful high-temperature alkaline flux. Promotes copper blues—good for thermal-shock bodies and matching glaze. Toxic in inhalation. 

Source: Clay: A Studio Handbook

Split

A specialized hardbrick, half the thickness of a standard brick. 

Source: Clay: A Studio Handbook

Specific Gravity

The weight or density of a liquid measured in proportion to that of water. A glaze with a specific gravity of 1.2 is 1.2 times as dense as water per unit of measure.

Source: Clay: A Studio Handbook

Solvent

An agent that acts to accelerate the dissolution of a more resistant material. In glaze maturation, the flux-glass-former combination acts as a solvent on alumina. 

Source: Clay: A Studio Handbook

Solution

A liquid mix where the components are fully dissolved (as in a water/soda ash solution for vapor-glazing), where materials will not settle out via gravity. 

Source: Clay: A Studio Handbook

Softbrick

Insulating firebrick. 

Source: Clay: A Studio Handbook

Soda Feldspar

Na2O×Al2O3×6SiO2—feldspars contributing sodium (and potassium), primarily as a high-temperature flux.

Source: Clay: A Studio Handbook

Soap

A specialized hard brick shape, half the width of a standard brick. Often used for posts in salt and wood firings. 

Source: Clay: A Studio Handbook

Soaking

During firing or cooling ramp, the act of holding kiln at steady temperature for a period of time to allow proper formation or maturation of certain clay and glaze effects. 

Source: Clay: A Studio Handbook

Slumping

Process of creating ceramic wares with a slump-mold. Firing defect where glassy-phase begins to dissolve sintered structure in clay, causing it to sag and deform. 

Source: Clay: A Studio Handbook

Slump Mold

A typically shallow frame or mold into which a slab of clay is allowed to fall or settle in order to form a vessel. These can be frames with no bottom. 

Source: Clay: A Studio Handbook

Slip Trailing

Application of decoration to wet or leather-hard clay by flowing on lines of slip with a fine pointed dispenser, such as a rubber syringe. 

Source: Clay: A Studio Handbook

Slip Resist

Decorating technique where resist materials are applied to prevent slip from adhering to some areas. 

Source: Clay: A Studio Handbook

Slip Glaze

A glaze with slip-clay or earthenware clay contributing the primary flux. 

Source: Clay: A Studio Handbook

Slip Clay

A naturally occurring clay that contains a high enough component of flux to form a glaze at high-fire temperatures. 

Source: Clay: A Studio Handbook