Introduction to Clay Mrs. Swapp Ceramics 1-2 Introduction to Clay Mrs. Swapp

Essential Question How is clay made? How will basic knowledge of clay conditions, tools, techniques, and processes provide a foundation for clay artworks?

What is Ceramics? Ceramic- clay that has been fired to a state of chemical conversion. This process gives the material strength and permanence Ware- means pottery Ceramicist- an artist that works with clay as their chosen medium.

Using Clay Clay Bodies Stages of Dryness Shrinkage Porosity and Vitrification Storage and Reclaim Clay Prep

Clay Bodies Earthenware the most prevalent and commonly used clay Firing temperature is low( around 1940 degrees F or 1060 degrees F Contains iron oxide (most common red clay) Stoneware Fired at a much higher temperature Peak temperature of 2200 degrees F Best for functional ware to hold food and drink Contains metals and minerals that alter color from light gray to dark brown Porcelain Refined stoneware White and translucent Delicate, smooth, and creamy consistency Picks up textural details

Stages of Dryness Small pieces can dry quickly but larger works need to dry at a slower pace. (crack, warp, or separate) Cover with plastic to control drying time Can cover pieces you know will dry faster Remove clay when work is completely dry (can only fire when completely dry)

Stages of Clay Slip Wet/Plastic Leather Hard Bone-dry Greenware Bisqueware Glazeware

Slip Stage of clay when there is a considerable amount of water Slip can be used as a glue to join to pieces of clay (score and slip Slip can also be used for surface decoration

Wet/Plastic Most malleable state Fresh out of the bag Ideal for constructing pinched or coiled forms because it is soft and pliable

Leather-hard Cracks when bent Best state to construct rigid forms with slabs (ex. Box) Still have enough moisture to be joined

Bone-dry All moisture has evaporated Feels cool to the touch if there is still moisture, if it is room temperature it is bone-dry Cannot bend, shape, or join pieces of bone-dry clay

Greenware Anything before firing

Remoistening Clay Cannot combine, cut or shape clay that is past the leather-hard stage. Only join clay when they are at the same stage (add moisture to harder form) Remoisten stiff or leather-hard stage spray with water and place under plastic Monitor the piece and add clay when needed, do NOT add too much water Overdoing it with water will cause a piece to fall apart or break in the kiln Don’t remoisten a bone-dry clay form because it will dissolve

Bisque Ware After the 1st Firing (bisque fire) Kiln- a device to fire ceramics Hardens the clay and clay becomes white (when using white earthenware) All moisture is removed Some glazes can be applied to greenware, but more commonly glaze after Bisque Fire Cone- an elongated pyramid of ceramic material that bends at a specific temperature in the kiln. CANNOT CHANGE THE SHAPE OR RECYLCE

Glaze Ware After 2nd Firing (glaze fire) GLAZE- a liquid mixture containing a glass former that is applied to the surface of a clay body. Melting Point: during firing when the glaze fuses to the ceramic surface, creating a permanent glass-like coating.

Shrinkage Clay is at its greatest volume when wet, as it dries it will shrink When fired clay will shrink even more Different clays shrink at different rates, earthenware shrinks about 7%

Porosity and Vitrification Porosity- the state of clay fired to a low temperature; pores remain open enough for water to seep through Vitrification- the process when a glaze or clay body is fired to a dense, nonabsorbent stage. (water cannot seep through at this stage)

Reclaiming Clay needs to be BONE DRY (break up clay into small pieces and let it dry) Add water until fully submerged. Wait. Should turn to mush. Pour out any excess water, then add dry clay Wedge Fun fact: Clay like cheese or wine improves with age. In Japan, clay is sometimes dug up, prepared, and then buried again for future generations to unearth and use!

Clay Prep Wedge: loosening up the clay and making sure it is well mixed. Removes any air bubbles that could make the form explode in the kiln. If the clay is sticky, add dry clay and wedge until the right consistency When cut in half, the clay should be flat and completely smooth

The End! (For now..)