CERAMICS VOCABULARY (revised 4-9-12)
1)Clay: A decomposed granite-type rock. To be classified as clay, the decomposed rock must have fine particles so that it will be plastic. (free of vegetable matter) (alumina & silica & water)
2)Primary clay: Clay found at its original site where the parent rock disintegrated.
3)Secondary clay: Clay that has been transported by water, ice, and natural occurrences.
4)Earthenware: Low fire pottery, usually red or tan in color. (below cone 03)
(Lots of iron)
5)Stoneware: a high fire ware (above cone 6) with very little absorbency.
6)Composite: A mixture of clays combining heat resistant and shrinkage qualities of various clays
7)Grog: Hard fired clay that has been crushed or ground to various particle sizes; used to reduce shrinkage in such ceramics products as sculpture and architecture.
8)Plasticity: The quality of clay that allows it to be manipulated and still maintains its shape without cracking or sagging.
9)Short:Describes clay that lacks plasticity (not enough moisture).
10)Leatherhard: The condition of the raw ware when most of the moisture has left
the body but when it is still plastic enough to be carved or joined.
11)Bone Dry: Clay that is completely absent of moisture, and therefore ready to be fired.
12)Greenware: Pottery that has not been bisque-fired.
13)Bisqueware: Unglazed ware fired to a temperature sufficient to harden
but not mature the body.
14)Wedge: Kneading plastic clay with the fingers and heels of the hands in a rocking motion: Forces out trapped air pockets and develops a uniform texture.
15)Slip: A clay in liquid suspension.
16)Scoring: Scribing or roughing up the surface of the clay prior to joining two pieces.
17)Burnish: Using a smooth object to polish the surface of leather hard clay.
18)Sgraffito: Decoration achieved by scratching through colored slip or a glaze to show the contrasting body color beneath.
19)Incising: Engraving a decoration into unfired clay.
20)Paddling: Striking the seam between two joined pieces of clay using a flat piece of wood.
21)Luting: Attaching two pieces of leather hard clay with slip
22)Firing:Heating clay in a kiln to a specific temperature
23)Kiln:A furnace made of refractory clay materials for firing ceramic products.
24)Kiln furniture: Refractory shelves and posts upon which ceramic ware is
placed while being fired in the kiln.
25)Kiln wash: A protective coating of refractory materials applied to the surface of
shelves and kiln floor to prevent glazes from fusing the ware to the shelves.
26)Refractory: The quality of resisting the effects of high temperatures.
27)Pyrometric cone: Small triangular cones made of ceramic materials compounded to bend and melt at certain temperatures, thus allowing the potter to know the firing is complete.
28)Vitrification:The process of becoming glass-like. This is the last step in the firing cycle, and occurs at different temperatures with different clays.
29)Shrinkage:Contraction of the clay in either drying or firing.
30) 8%-12%: The amount of shrinkage from moist clay to fired clay.
31)Thermal shock: A heated ceramic piece is required to cool too quickly,
causing cracking and splitting.
32)Oxidation: The kiln chamber contains an ample supply of oxygen.
33)Oxide:When oxygen combines with another element. Metallic oxides are often used as coloring agents in the glaze.
34)Reduction Firing: Removing oxygen during the firing of certain glazes
35)Raku:Glazed, groggy earthenware; originated in Japan. Used for tea ceremony.
36)Coiled pottery:A hand method of forming pottery by building up the walls with rope-like rolls of clay and then smoothing over the joints.
37)Slab: A handbuilding method in which forms are created by joining flat pieces of clay.
38)Glaze:A liquid suspension of finely ground minerals that is applied by brushing, pouring or spraying. Glaze ingredients will melt together during firing to form a glassy surface coating.
39)Engobe: A combination of colored slip and glaze used in coloring greenware or bisqueware.
40)Throwing: Forming plastic clay on a potter’s wheel.
41)Sagging:The condition of clay when there is too much water.
42)Foot: The round base of a pottery piece.
43)Bat: A disk or slab of plaster of paris on which pottery is formed or dried. It is also used to remove excess moisture from plastic clay.
44)Embossing: A form of decorating in which slightly raised forms are added to the clay
45)Relief: A sculpural form that is raised on one side and flat on the other.
46)Impressing: Decorating a clay piece but pushing a textured object
into the surface of the clay while it is still fairly plastic
47)Flux: is an element or compound used in clay bodies or glazes which lowers the
melt temperature of that clay body or glaze.
48)Flange: a projecting rim or collar on a piece that serves to hold it in place or give it strength.
49)Lug:handles that are a kind of flattened knob attached to the side of pottery.