Glossary Terms (Simple)

Bag Wall

Refractory wall in some fuel-burning kilns to deflect heat and flames from direct contact with the wares.  

Source: Clay: A Studio Handbook

For more information on loading and firing wood kilns, watch Simon Levin's informative video!

Source: Clay: A Studio Handbook

Back Pressure

In a fuel kiln, the internal pressure resulting from proper balance of combustion pressure and damper setting, resulting in more economical and efficient heatwork.  

Source: Clay: A Studio Handbook

For more information on gas kiln design and firing, download this freebie!

Avery Kaolin

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

Source: Clay: A Studio Handbook

Ash Slagging

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

Source: Clay: A Studio Handbook

Applique

Low-relief clay shapes added to scored, slurried leather-hard surface for decoration.  

Source: Clay: A Studio Handbook

Want more? Kari Radasch explains her process for decorating with applique in this Daily post!

Annealing

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

Source: Clay: A Studio Handbook

Anagama

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.  

Source: Clay: A Studio Handbook

Want more? Check out this great article on building an anagama for a high-school ceramics class!

Amorphous

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

Source: Clay: A Studio Handbook

Aluminum Silicate

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.  

Source: Clay: A Studio Handbook

Alumina Hydrate
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.  

Source: Clay: A Studio Handbook

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

Source: Clay: A Studio Handbook

Alkaline Earths
4 Simplified periodic table showing elements used in ceramics. The gaps in the table are elements not used in ceramics.

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

Source: Clay: A Studio Handbook

Dive deeper into this pottery term with this Ceramics Monthly Technofile article!

Alkaline
Basic, opposite of acidic—chemical nature of many fluxes.  

Source: Clay: A Studio Handbook

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

Source: Clay: A Studio Handbook

Agateware

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

Source: Clay: A Studio Handbook

Want to learn more about this ceramic term? Check out this post in the Daily!

Additive A

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.  

Source: Clay: A Studio Handbook

Acid

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

Source: Clay: A Studio Handbook