Oct. 2, 2013
New vocabulary for Oct.
Hand Building Ceramics
Clay – Decomposed rock (fine grain) forming a malleable material. (Al2O3 -2SiO2 -2H2O)
Plasticity – The quality of clay that allows it to be manipulated and still maintain its shape without cracking or sagging.
Green ware – Clay that has not been fired.
Wet clay – Clay in a moist plastic state.
Leather hard clay – Clay in a stiff but sufficiently moist state to permit joining.
Bone dry clay – Clay in a completely dry state and ready to be bisque fired.
Firing – Heating a kiln to bake ceramics.
High fire – Ceramics baked in a kiln to a high enough temperature to create maturity.
Maturity – The temperature at which a clay body develops desirable characteristics of maximum non-porosity or hardness. It also occurs when the glaze ingredients enter into complete fusion and bonds firmly with the clay body.
Bisque – [Bisque ware] – Unglazed ware fired to a temperature sufficient to harden but not mature the clay body. [Bisque Firing] – The first firing of clay.
Hand building – One of several techniques to make clay objects using only the hands and simple tools. Some of these techniques are: coiling, pinching, and slab building.
Throwing – Creating pottery on the potter’s wheel.
Slip – Clay in liquid suspension or form. It is often the consistency of thick cream.
Score and Slip – A method of joining two pieces of clay together. Scoring is when scratches are made in the two pieces of clay that are intended to be joined. Slip is added to one side of the scored clay and then the two pieces are pressed together. The slip acts like glue. This method does not work on bone dry and fired clay.
Clay shrinkage - Clay (water based) contracts as the water evaporate. Contraction or shrinkage also occurs in the firing process as the clay fuses together.
Grog – Hard fired clay that has been ground into fine particles. It is added to clay to reduce clay shrinkage. It can add stability, but often makes the clay feel grainy.
Parts of a VASE (compare to the human body)
Mouth – The opening at the top of the vase. Lip – The top edge of the vase where the opening is located. Neck – The elongated upper part of a vase. Body – The main part of the vase. Foot rim – The bottom ¼ inch of the vase. Foot – The bottom or underneath part of a vase, which touches a table.