Basic Ceramic Terms

Clear Glaze

A clear glass coating to be used alone to achieve shiny clay color or with underglaze.

Potters Wheel

A device with either a manual (foot powered) or an electric rotating wheel head used to sit at and make pottery forms.

Bat

A flat disc made out of plaster, wood, or plastic which is affixed to the wheel head for turning a pot on the wheel.

Kiln

A furnace of refractory clay bricks for firing pottery and for fusing glass.

Wedging

A method of kneading clay to make it homogenous (evenly mixed), remove air bubbles, and to change the water content by cutting and rolling.

Clay

A natural material extracted from the earth's crust. Made of alumina + silica + water.

Coil

A piece of clay rolled like a rope, used in making pottery.

Mold

A plaster shape designed to pour slip cast into and let dry so the shape comes out as an exact replica of the mold.

Rib

A rubber, metal or wooden tool used to facilitate wheel throwing of pottery forms.

Glaze

A thin coating of glass. An impervious silicate coating, which is developed in clay ware by the fusion under heat of inorganic materials.

Firebrick

An insulation brick used to hold the heat in the kiln and withstand high temperatures.

Foot

Base of a ceramic form.

Extrusion

Clay forced through a die to form uniform shapes.

Slip

Clay mixed with water to a mayonnaise consistency. Used in casting and decoration. 50% Water

Bone Dry

Completely air dried. 2% Water

Slab

Creating a form utilizing flat pieces of clay.

Throwing

Creating ceramic shapes on the potter's wheel.

Ceramics

Creation of an object out of clay.

Earthenware

Fires at low temperature, is porous and chips easily. Glazed pottery is fired to a temperature of 1,830 ‐ 2,010 degrees Fahrenheit. Available in red or also white.

Bisque Fire

First firing, without glaze. Slips can be used in a bisque firing.

High Fire Glaze

Glaze which is non pourous, is safe for use on functional ware, is not brushed on and is fired at about 2300F.

Low Fire Glaze

Glaze which is pourous, best used on nonfunctional objects and is fired at about 1800F.

Stoneware

High Fire, holds water without glazing. Porcelain: Very high firing clay, white and translucent when fired. Difficult to work with.

Pinch

Manipulate clay with you r fingers and your palm to form a hollow shape.

Bisque

Pottery which has been fired once, without glaze, and can not be recycled. 0% Water

Kiln Furniture

Refractory posts and shelves used for stacking pottery in the kiln for firing.

Leatherhard

Stage of the clay between plastic and bone dry. Clay is still damp enough to join it to other pieces using slip. For example, this is the stage handles are applied to mugs. 10% Water

Centering

Technique to move the clay in to a symmetrical rotating axis in the middle of a wheel head so you can throw it.

Glaze Firing

The final firing, with glaze.

Vitrification

The firing of pottery to the point of glossification.

Firing Range

The range of temperature at which a clay becomes mature or a glaze melts.

Needle Tool

These long heavy needles set into wooden, metal, or plastic handles are one of the most versatile tools in pottery.

Fettling Knives

These tools are useful in cutting large lumps of clay, cleaning edges of cast pieces.

Fire

To heat a clay object in a kiln to a specific temperature.

Dry‐Foot

To keep the foot or bottom of a pot free from glaze by waxing or removing the glaze.

Score

To scratch lines in unfired clay before applying moisture or slip to attach tow pieces of clay.

Cut‐Off Wire

Tool used to cut chunks from a large piece of clay. Also used for cutting pots off the pottery wheel.

Greenware

Unfired pottery. Ready to be bisque fired.

Loop Tool

Used for carving out solid areas of clay or for trimming the bottom of wheel thrown pots.

Clay Rasp

Used for smoothing very uneven ares of leatherhard clay.

Scrappers

look a lot like ribs, but are lighter and used to smooth wet and soft leatherhard greenware and are steal, rubber, or wood.