ART 105 Ceramics I Midterm Vocabulary Review

Vocabulary flashcards covering hand-building techniques, clay stages, firing methods, glaze defects, and firing atmospheres for ART 105 Ceramics I.

Pinching

Forming a pot by the compressing action of fingers and thumb, growing the pot from a ball of clay by pushing a hole in it, progressively thinning the walls, and slowly rotating it in one hand while pinching with the other.

Coiling

Hand-building a pot using long rolls of clay, where each roll is integrated with the previous one so that its separate identity as a roll is lost.

Slab

A sheet of clay that can be cut into shapes and used to form a ceramic structure, usable in either a soft or stiff state to construct the projected piece.

Leather hard

The condition of a clay body when much moisture has evaporated but the clay is not totally dry; the state where clay is strongest and when carving, burnishing, or joining slabs is often done.

Bone dry

The state when nearly all moisture has evaporated and clay is ready to be fired; the structure is very weak and brittle at this point.

Green ware

Unfired clay; the stage of a ceramic piece right before being bisque fired.

Bisque firing

The process of firing unglazed ceramic ware at a low temperature ($1830\text{ degrees Fahrenheit}$), resulting in ware that is quite porous, not as strong as when fired to final temperature, and ready to be glazed.

Slip

Liquid clays that can be painted, stenciled, or sprayed onto a clay surface to change the surface color or texture.

Glaze

A layer of glass fused onto a ceramic piece of bisque ware that is decorative, provides color, shine, and textural contrast with the clay, and increases the strength of the ware.

Glaze Firing

Typically the second firing of ceramic ware which has been coated with glass forming materials.

Mishima

A method of creating an inlaid effect by applying contrasting slip into a design carved into leather-hard clay, followed by scraping off the excess slip once it stiffens.

Sgraffito

A form of decoration made by scratching through a slipped surface to reveal a lower layer of clay of a contrasting color.

Pyrometric Cones

Specially formulated material used to gauge the temperature during the kiln firing process by melting at certain temperatures.

Cone 06

A pyrometric cone that melts at $1830\text{ degrees Fahrenheit}$, used for Bisque firing.

Cone 04

A pyrometric cone that melts at $1940\text{ degrees Fahrenheit}$, used for Low fire glaze.

Cone 6

A pyrometric cone that melts at $2200\text{ degrees Fahrenheit}$, used for Mid range glaze.

Cone 10

A pyrometric cone that melts at $2300\text{ degrees Fahrenheit}$, used for High fire glaze.

Oxidation

A kiln atmosphere where oxygen is present; good for producing consistent, predictable glazes.

Wedging

Kneading clay by hand to produce a homogeneous mixture that is neither too wet nor too dry, aligning the hexagonal platelets of clay as water evaporates.

Pin Holing

A series of small pits in the fired glaze surface caused by dust, underfired bisqueware, glaze applied too thickly, or escaping gases; remedied by applying more glaze in the area and refiring.

Slip Trailing

A surface technique using a squeeze bottle or rubber bulb filled with colored slip to create decorations or energetic, expressive marks.

Crawling

A defect where glaze pools into droplets and exposes the clay body underneath, often caused by excessive handling of the bisque, dust, grease, lotion, or applying the glaze too thick.

Quartz Inversion

An irreversible chemical reaction that occurs at $1063\text{ degrees Fahrenheit}$ where applying heat converts brittle clay into hard ceramic, and silica undergoes a change in volume as water evaporates, causing forms to shrink.

Crazing

A network of fine cracks in a glaze occurring when there is greater contraction in the clay body than in the glaze; can be unintentional or intentional (known as a crackle effect on pottery exteriors or sculptures).

Scoring

Scratching clay surfaces to provide extra surface area for a sturdy join.

Reduction

A kiln atmosphere starved of oxygen, resulting in free carbons (carbon monoxide and carbon dioxide) pulling oxygen from metal oxides in ceramic materials; great for high firing red glazes.

Pouring

A highly accessible glaze application method performed on a clean, dust-free piece.