Ceramics Vocabulary Review

A comprehensive set of vocabulary flashcards for key terms and concepts in ceramics courses.

Bone dry

a term used to describe greenware pottery that has dried as much as possible before it has gone through its first firing (bisque firing). When held, bone-dry greenware is ashy-looking and no longer cool to the touch. The clay is very fragile in the bone-dry state.

Clay

a fine-grained, malleable material made from decomposed igneous rocks (like granite) that has disintegrated by weathering and movement by natural forces: classified as primary or secondary based on the distance traversed from their source (usually by water like a river… erosion). The further clay has traveled, the finer its particle size will be, resulting in greater plasticity. Clays are plastic due to water content, which is trapped at the molecular level and becomes hard, brittle, and non–plastic upon drying or firing

Clay body

Any blend of clays and non-plastic ceramic materials that is workable and that has certain firing properties, with dependable, regular results. A clay body is composed of specific qualities (plasticity, color, temperature, shrinkage, density, local material, cost), and to achieve maturity at various firing temperatures.

Greenware

Clay objects that have not yet gone through the bisque firing; greenware may be reclaimed.

Green Strength

The strength or fragility of the clay body before it undergoes the first firing.

Grog

clay that has been fired and then ground up (fine to coarse) to be used in the making of another clay body. Added to a claybody to reduce shrinkage as they dry and fire.

Leatherhard

One of the working stages of clay. At this stage, the clay is rigid but slightly malleable and cool to the touch. This is the ideal stage for trimming, carving, refining, slipping, and transporting your project. There is still a lot of added water in the clay body at the leatherhard stage, and it is too early to be bisque-fired in the kiln.

Particles (clay)

The clay in your claybody is a hexagonal particle with an electrical charge. The electrical charge makes the clay plastic. If the clay particles are not aligned correctly in a tight overlapping matrix we will experience a number of faults in our projects.

Reclaim Bucket

The place in the studio where unworkable greenware or unfired clay is placed to be recycled into plastic clay. Fired clay is NEVER put in the reclaim bucket.

Shrinkage

As the added water to a claybody evaporates, the clay object begins to shrink. On average, clay shrinks 10-15% from wet clay to the finished, fired ceramic object

Slip

Unfired Clay (clay body) and water. It may be used for joining two pieces of clay. Or it may be mixed with other additions, like colorants, for decorative surfaces. Like a piece of clothing, a slip must go underneath a glaze after it has been fired in a bisque firing.

Timing

An important component of working with clay is your ability to control the different stages of the clay’s malleability. There are three things you need to learn to be successful at ceramics: Timing, Timing, and Timing!

Wedging

Any one of carious methods of kneading a mass of clay to expel the air, get rid of lumps, and prepare a homogeneous material. The three ways we wedge clay are: Wire wedging, the Bullshead/Ramshead method, and the Spiral or Chrysanthemum method.

Dart

A sewing technique applied to ceramics. A dart or diamond shape is cut out of the side of a piece, and when put back together, creates an altered form. Often used by potters to take cylinders and bowls out of the round.

Throwing

forming objects on a potter’s wheel using a clay body with plastic qualities.

Plasticity

the malleable workability of clay. Powdered clay and water (usually about 25%) are mixed to make a plastic Clay body. Once the clay has dried to a bone-dry stage it can no longer be made plastic with water and must be slake down and reclaimed.

Warping/Cracking

changes/faults in the form of the clay body that is caused by insufficient compression and intention to minimize these two faults (Projects that are visibly warped and cracked will not be accepted for a grade)

Ware

a general term applied to any ceramic- earthenware, stoneware, or porcelain, in the green, bisques, or fired state

Banding Wheel

a turntable that allows for easy in the round access to project. Banding wheels are traditionally used during the decorating stages, revolved with one hand to turn a piece of pottery or sculpture while decorating it with the other hand… often to create concentric bands of color on wares.

Bat

A flat disk usually made of wood, plaster or plastic that easily detaches form the wheel head; used to transport a pot without touching it.

Centering

The act of forcing a lump of clay by hand into a symmetrical form at the center of a spinning potter’s wheel in preparation for throwing pottery.

Coning

the up and down stage of throwing that aids in aligning the clay particles and centering the clay

Extruder

a mechanical aid for forming moist clay by pressing it through a die. This causes the clay to take the shape of the die quickly into many forms (think tubes, tiles, sewer pipes, etc…)

Finger Rings

The spiral rings that form on clay wall during the pulling process. The rings correlate to hand speed: infrequent lumpy ring mean you are moving your hand upward to fast.

Foot/Foot Ring

the bottom of a ceramic vessel, often create through the trimming process. The foot of all projects must be completely free of slip and glaze in order to be fired. Glaze should be wiped back a minimum of ¼ in on all projects and upwards of one inch on projects with runny glazes (see Roberta or an Instructor for approval).

Hump (Throwing/Trimming):

A large lump of clay used for speed by production potters. This technique allows you to throw multiple smaller pieces from one large piece of clay.

Hump/Slump Mold:

a mold of plaster or terra cotta, or a found object, over which a slab or clay can be laid to shape as is stiffens

Lip

The top edge of a ceramic vessel.

Mishima

A surface decoration that includes inlaying a line of clay slip or underglaze into an incised or carved line on the surface of greenware.

Motif

A shape or an image within a pattern or alone, as a decoration.

Pulling

the term we use to lift the clay wall after centering and opening.

Press mold

Any mold made from plaster, fired clay, or a found object into which the damp clay can be pressed to reproduce the shape of the mold.

Resist

a method of applying a covering material such as wax or paper to greenware, to mask that area when applying slip over top.

Score

scratching or abrading the surface of something to create an ideal joining surface. Must be done to attach two pieces of clay together.

Sgraffito

decoration of pottery made by scratching through a layer of colored slip to the differently colored clay body underneath.

Short

clay that is not plastic. Cracks will form on handling after brief manipulation

Slab roller

A mechanical device used for rolling our slabs to a set, consistent thickness.

Spout

The part of a vessel used for pouring- it may be open like a pitcher spout or closed like a teapot spout. They can be wheel thrown or hand built.

Sprig/Sprig Mold

A thin piece of clay applied to the surface of leather hard clay that creates a low relief or additive decorative element to potter. Probably named from the branch themed ornaments that historically decorated pots (especially German). The mold is made with soft clay that is pressed over sculpted oil clay and then fired to bisque temperature.

Undercut

A bevel cut into the base of a freshly thrown pot- it makes centering trimmed forms easier or creates a finished edge if form are thrown efficiently.

Slake

the breaking down of clay (bone dry) in water to produce reclaimable slurry. Note: once clay pieces have been fired they cannot be reclaimed or slaked down!