Ceramic Terminology Flashcards

Comprehensive vocabulary flashcards covering basic ceramic terms, stages of clay, forming methods, surface decoration, studio tools, and firing defects.

Functional Ceramic Work

Work that is primarily used for the preparation, presentation and storage of food. Also referred to as Pottery.

Non-Functional Ceramic Work

Work that bears resemblance to functional work, but in all practical scenarios cannot be used. Sometimes referred to as decorative (e.g., a teapot that is 3 feet tall).

Sculptural Ceramic Work

Work that may or may not be representational, whose formal and/or conceptual properties adhere more to the tradition of Sculpture than the tradition of Ceramics.

Clay

Fine-grained sediment, with particle-size less than two-thousandths of a millimeter, and which becomes plastic when wet.

Body

The term used to describe clay and any inclusions present in it, particularly prior to firing, though it may also describe the finished product (the body of a pot).

Plasticity

The ability of clay to be molded and maintain its shape, resulting from water being present between clay particles allowing them to glide over one another.

Slip

A smooth mixture of clay and water applied to the surface of work to create color and texture, or used as an adhesive to attach two or more forms together.

Slurry

A non-homogenous mixture left in a bucket after throwing, which is added to dry clay for recycling or reuse.

Leather-Hard

The stage in clay drying when most physical water has evaporated. Surface treatments, joining, and additions are made at this stage, and it cannot be re-moistened back into working clay.

Greenware

Also known as Bone Dry; the stage when all physical water has evaporated, the clay has changed color, and is very fragile and ready to be bisque fired or recycled.

Bisque

Refers to both the firing process and the work itself. Removes chemical water present in the work to convert clay to ceramic. Bisque ware will never be clay again.

Glazeware

Ceramic work that has been covered with Glaze (silica, fluxes, and metallic oxides) and becomes vitrified or glasslike when fired to the desired temperature.

Shrinkage

The physical change to clay as physical water evaporates during drying, bringing particles into contact, and during firing at temperatures exceeding approx. $1650^\circ\text{F}$. Clay shrinks approx. $8\text{--}12\%$.

Firing

The process whereby clay is converted to ceramic. Requires temperatures in excess of $1000^\circ\text{F}$ to drive off chemically combined water.

Cone

Common term for a Pyrometric Cone manufactured by the Orton Cone Company. A triangular shaped piece of ceramic materials formulated to melt at a specific temperature to monitor kiln heat.

Kiln

A structure for firing ceramics made out of refractory (heat resistant) materials.

Reduction Firing

Atmosphere inside a kiln deprived of most oxygen (usually in fuel-burning kilns like natural gas or wood), causing desirable chemical reactions (e.g., Copper Oxide turning red).

Oxidation Firing

Oxygen-rich atmosphere inside a kiln (usually done in electric kilns), causing desirable chemical reactions (e.g., Copper Oxide turning green).

Wedging

Method of preparing clay for working by hand or wheel, where clay is cut, slammed, and kneaded to make it homogenous and force out trapped air.

Hand Building

Any method of forming clay that does not directly utilize the potter's wheel.

Scoring

Process of scratching the surfaces of two pieces of clay prior to applying slip for attachment.

Coiling

Vessel forming method using coils of clay stacked on top of one another.

Slab

Vessel forming technique where clay is rolled out into sheets and cut to desired shapes (can be stiff or soft).

Extrusion

Vessel forming method where clay is placed inside an Extruder machine and forced through an opening of a desired shape.

Pinching

Vessel forming method where the clay is compressed between the fingers.

Mold

Use of a stiff form to press or drape clay into or onto (Slump, Hump, or Press Molds), or plaster forms used to cast slip.

Modeling

Sculpture process allowing the maker to add, remove, and reform elements of work, commonly used in figurative ceramic sculpture.

Throwing

Any method of forming clay that utilizes the potter's wheel.

Centering

Act of condensing a ball of clay into the center of the wheel through centrifugal force and physical force exerted by the potter.

Opening

Second stage of wheel throwing where a tool or finger is placed into the center of the clay, displacing clay to create the vessel base.

Raising

Displacing clay upward to create walls by pressing from the outside with the dominant hand and supporting from the inside with the other.

Shaping

Using tools (usually ribs) to refine the vessel into the desired form on the wheel.

Trimming

Process of removing excess clay from the base of a leather-hard wheel-thrown pot placed upside down on the wheel, or removing wet clay at the base using a throwing knife.

Finishing

Final stages of forming including smoothing rough edges and surfaces and clearing away debris before firing.

Sgraffito

Surface decorating technique where colored slip is applied to leather-hard clay and then carved away after setting to reveal the underlying clay color.

Incising

Carving clay away from the surface at the leather-hard state using a variety of tools.

Mishima

A technique developed in Korea (also called Inlay) where a pattern is incised, filled with slip, allowed to set, and scraped smooth to reveal the underlying pattern.

Sprigging

An embossing technique where molded clay additions are pressed onto the surface of a leather-hard vessel.

Resist

Use of a stencil, tape, or wax to mask areas of a vessel's surface before applying slip or glaze.

Wire Tool

Tool used to cut desired amounts of clay as well as remove work from the wheel.

Rib

Tool made of wood, metal, rubber, or plastic used to compress, shape, or smooth clay on the wheel or during hand-building.

Needle Tool

Tool used for scoring, cutting, piercing clay, and gauging thickness.

Throwing Knife

Wooden tool primarily used to trim excess wet clay at the base of a vessel before removing it from the wheel.

Rasp

Tool used to trim away excess clay, refine forms, or add decorative texture at the leather-hard state.

Bat

Surface placed on the wheel for throwing, primarily used for large-scale work or pieces that are difficult to remove when wet.

Calipers

Tool used to gauge the width of an opening when making lidded forms.

Fettling Knife

Knife primarily used to cut soft slabs.

Utility Knife

Knife used to cut and trim leather-hard clay; must not be used directly on canvas surfaces.

Dunting

A type of crack occurring from stresses during firing and cooling, appearing as long, clean body cracks with sharp edges.

Bloating

Blistering of a pot wall during firing caused by the expansion of unreleased gases after fusion, usually resulting from over-firing.

Pinholing

Glaze defect appearing like tiny eruptions or bubbles, caused by unburned clay impurities from bisque firing or rapid glaze cooling.

Crawling

Glaze defect where glaze separates from the vessel surface, usually caused by surface oil, dirt, or overly thick glaze application.

Shivering

Glaze defect where the clay shrinks at a higher rate than the glaze, causing the glaze to flake or peel off after firing.

Crazing

Glaze defect characterized by a network of cracks, occurring when the glaze shrinks more than the clay during rapid cooling.

Blow-up / Blow-out

Flaw occurring in early firing around $200^\circ\text{F}$ when trapped physical water in non-bone-dry clay turns to steam and explodes.