Ceramics Vocab

Clay

A compound of decomposed and altered feldspathic rock consisting of aluminum along with non-plastics, such as quartz, and organic matter.

Porcelain Clay

Pale body of primary clay with a distinctive ring

when struck.

Stoneware Clay

Secondary clays that are not as fine-grained as other clay bodies.

Absorption

The capacity of a material to soak up liquid.

Shrinkage

Contraction of the clay or glaze in either drying or firing.

Slip

A suspension of clay in water. (Glue, muddy clay)

Grog

Fired clay that has been crushed into granules which may be added to clay body to increase strength control drying and reduce shrinkage.

Plasticity

The quality of clay that allows it to be easily shaped and maintain its form

Leather-hard

The condition of raw clay when most of the moisture has evaporated leaving it still soft enough to be carved or joined to other pieces. (Hard enough to be carved)

Bone Dry

The condition of unfired clay that has no assorted moisture other than natural humidity. The form is ready to bisque fire.

Bisque Ware

Clay that has been fired once, unglazed.

Blowout

The explosion of clay in the kiln caused by the sudden

escape of steam, as a result of rapid heating of thick clay or the presence of impurities.

Blistering

Air bubbles which appear in a glaze after a fast firing

Wedge or Wedging

The process of kneading plastic clay with the fingers and heel of the hands in a spiral motion, which forces out trapped air pockets and develops a uniform texture or mixture of the clay body.

Pinch Technique

A hand-building method of construction where a ball of clay in the plastic state is repeadtedly pinched and turned between the thumb and four fingers to create a small pot or bowl.

Coil Technique

A hand-building method of construction, which utilizes rolls of clay or coil rope in the plastic state to build up walls that are then joined together either internally or externally. 

Slab Technique

A hand-building method of construction using clay in the leather-hard state that utilizes flat pieces of clay that must be joined together.  The technique is similar to creating a structure with wooden boards.

Throwing Technique

A hand-forming method of construction where a ball of clay is hollowed out on a revolving wheel head.  The change over from built forms to wheel pots seems to correspond with a change from women to men potters

Score

To scratch the surface of something to make it rough.  When done properly two pieces may be joined together to make one.

Hand Building

The forming of ceramics without a wheel, ( pinch, coil, slab).

Damp Box

A cabinet in which unfinished clay objects are stored to slow their drying.  *Plastic wrap is also used to keep clay damp

Kiln

A furnace for firing ceramic products.  Essentially a box of refractory bricks, into or around which heat is introduced either by combustion or by radiant heat. 

Pug Mill

A machine with paddle gear for grinding and mixing plastic clay.  The clay is mixed within the barrel and forced forward through the narrowing channel.

Bench Wheel

A small portable turntable used for rotating pottery in any state (except slip) in order to work on or decorate the pottery.  Also commonly referred to as a banding wheel because it is used to apply bands of color or texture. 

Slab Roller

A large piece of equipment that allows the artist to flatten out clay evenly throughout.  The slab roller replaces the old technique of using sticks or boards and a kitchen rolling pin.

Needle

Also known as a Pin Tool. A fine awl for cutting, piercing or scoring clay.

Rib

A wooden or metal tool for smoothing, or for assisting in throwing a pot on the wheel. There are also plastic/silicone ribs. The name was given to this tool because older potters used a bone for this purpose

Sponge stick

A natural or polyester sponge fastened to the end of a dowel or stick, and used for absorbing surplus water from pots during throwing.

Spatula tool

A tool with a flattened, curved and rounded end. This tool is used for designing and trimming excess fat off of a spinning form on the potter's wheel. A dull pencil is a good alternative.

Trimming tool

The only essential feature of a trimming tool is a short firm cutting edge that can be held at a right-angle to the rotating pot. These tools are also called “T-tools”- depending on the size one would use a small T-Tool (f) or large T-tool (g) to describe the tool needed for the job.

Wire Cutter

Two wooden handles connected with wire. Used to separate thrown pieces from the bat AND to cut the clay into smaller pieces.