Introduction to Pottery

What Is Clay? ● Informal definition: Essentially dirt and water. But mostly dirt.

What Is Clay? ● Formal definition: a special form of earth made from the decomposition of rock through the action of weathering. – For clay formation, moving water is usually the weather-er. ● Decomposed rock = silt – Silt is like very fine sand – Often found in river beds and beaches

● Silt and other bits of decomposed rock is carried in moving water (e.g. a river) and deposited wherever the water movement slows down. ● Treated/processed – Larger bits of rock removed, sand added (often) – Some of the water is drained out

● Clay can be found almost anywhere (even in the layers beneath dry desert sand—just needs water) ● What makes it good clay for art? → Plasticity – Plasticity refers to the capacity of a material to be molded or altered – Good plasticity = high capacity for alteration (w/out cracks or breakage)

Four Methods of Clay-Working ● Pinch ● Slab ● Coil ● Wheel

Processes and Terms ● Wedging – A particular way of pushing and pulling clay to remove air bubbles ● Kiln – A kiln used specifically for firing clay. They can reach temperatures in excess of 2500 degrees Fahrenheit

Processes and Terms ● Earthenware – General term for pottery that is not porcelain or another specific type of clay ● Slip – “liquid” clay, or clay with a lot of water added to it. Used as an adhesive to bind clay to other pieces of clay and for mold- pouring.

More Processes Terms ● Leather-hard – The state of clay after drying for several hours. It is no longer moldable, but too wet to be fired. ● Greenware – Dried, unfired clay that is ready to go in the kiln ● Bisque – The state of clay after it has gone through a low- fire kiln cycle (about 1800 degrees Fahrenheit). Can be painted, glazed, or left as is.

Last One ● Glaze – Used to decorate clay that will hold liquid and/or food. It is made of tiny glass particles that have been mixed with pigment and other minerals, suspended in liquid. – Melts at high temperatures and forms a glass surface that seals out moisture. – Bisque clay is usually painted with glaze and goes through a high-fire kiln cycle

● NEVER pour clay down the sink. Ever. ● There will be a designated bucket of water in which you will rinse your hands.

● Wash your hands with soap and water AFTER rinsing the clay off in the bucket. – Make sure you do this.... clay + 30 pairs of hands + standing, room-temperature water = an exciting mini-ecosystem