Clay Notes Where does clay come from Clay

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Clay Notes

Clay Notes

Where does clay come from? • Clay comes from the ground, usually near areas

Where does clay come from? • Clay comes from the ground, usually near areas where there is water. – Topsoil is top layer of ground, clay found below topsoil – Clay found near lakes, rivers, and reservoirs – Can also be found in dry areas in powdered form – Clay is mined in Wisconsin

How does clay get from the ground to PHS? • Clay is mined from

How does clay get from the ground to PHS? • Clay is mined from the ground • Raw materials are added to clay and mixed • Clay is filtered to remove unwanted material • Extra water is removed from clay • Air is removed from clay • Clay is formed into blocks and shipped to schools, businesses, and artists

Different types of clay • Clay gets its color from elements and materials in

Different types of clay • Clay gets its color from elements and materials in the ground. Traditionally red, grey, and white. • Earthenware – low fire clay, easy to work with, needs glaze to hold water • Stoneware – medium fire clay, very hard and durable, holds water without glaze • Porcelain – high fire clay, difficult to work with, very strong

Important Clay Terms • Wedge – process of blending clay to remove air bubbles

Important Clay Terms • Wedge – process of blending clay to remove air bubbles • Plasticity – how flexible the clay is, depends on the moisture of the clay • Porosity – how much water the clay can absorb • Shrinkage – how much clay shrinks as it dries, is fired, and is glazed

Important Clay Terms • Greenware – clay that has been shaped, but not fired

Important Clay Terms • Greenware – clay that has been shaped, but not fired in the kiln, very fragile • Leather hard – clay is dry, but not all the way • Bone dry – clay is all the way dry, nothing can be added at this point • Bisque – clay has been fired once and is hardened, but not glazed or painted

Greenware, before being fired in a kiln Bisque pottery

Greenware, before being fired in a kiln Bisque pottery

Clay Processes • Pinchpot – Pinching a ball of clay into a functional bowl

Clay Processes • Pinchpot – Pinching a ball of clay into a functional bowl • Coil building – Rolling and stacking coils on top of each other to create a cup, bowl, vase, etc.

Pinch pot Coil building

Pinch pot Coil building

Clay Processes • Slab building – Rolling slabs of clay to usually create boxes

Clay Processes • Slab building – Rolling slabs of clay to usually create boxes or vases • Throwing – Using a potters wheel to create perfectly circular cups, bowls, plates, etc.

Throwing on a wheel Slab building

Throwing on a wheel Slab building

Clay Processes • Scratch and slip – Used to attach clay to clay. Placing

Clay Processes • Scratch and slip – Used to attach clay to clay. Placing small scratches on the surface of the clay and using slip (clay glue) to hold clay together.

Scratching clay Clay slip

Scratching clay Clay slip

Clay Decorating • Glaze – Used to add color to finished clay pieces. Traditionally

Clay Decorating • Glaze – Used to add color to finished clay pieces. Traditionally painted over bisque fired clay, then fired again to reveal colors and patterns • Paint – Acrylic, latex, and watercolor can be added to the surface or bisque fired clay. (Room temperature glaze)

Glaze after kiln Glaze before kiln

Glaze after kiln Glaze before kiln

Glossy and matte glaze

Glossy and matte glaze

Clay Decorating • Kiln – Clay oven that operates at extremely hot temperatures –

Clay Decorating • Kiln – Clay oven that operates at extremely hot temperatures – Usually around 1400 – 2500 degrees F – Used to turn brittle, dry clay (greenware) into strong, durable clay – Used to alter dry, unattractive glaze into colorful, attractive glaze

Man made brick kiln Modern electric kiln

Man made brick kiln Modern electric kiln

Clay Tools • • • A A. Fettling knife B. Sponges C. Ribbon or

Clay Tools • • • A A. Fettling knife B. Sponges C. Ribbon or Loop tools D. Rib Tool: used to smooth out the surface of clay pots E. Banding wheels: used for hand building, coiling, and decorating C E D B