VOCABULARY:

Here are some terms and reference words you will need to know before beginning with clay.

Clay body = the earthy mixture of sediment, water, and other natural elements that are wedged together to form a physical body that becomes permanent when fired and heated to a high temperature, depending on the type of clay. Clay comes in many forms: Earthenware (Low Fire White Clay or Red Clay), Stoneware (Mid to High Fire), and Porcelain.  In our classes, we use the Earthenware and the Stoneware, not Porcelain.

Cone = the cone is a ceramic term provided to the temperature equivalent a clay body needs to fire at in order to become permanent. Cones vary from Low Fire 022 (1124 F) to High Fire 13 (2455 F). Some kilns heat to Cone 23, but we will never cross that in school. Clays fire at a variety of temperatures due to the earthy chemical make-up of the clay body and the glaze.

Stages of Clay = clay comes in a variety of stages depending on its moisture level and workability. 

• Slip = this is the wettest clay in liquid mud form, simply mixed with water that can be used as a clay adhesive when attaching pieces of clay together or when applying a slip cast to a mold.

• Plastic = the form of workable and moldable clay, right from the block. This is the easiest clay to bend and manipulate.

• Leatherhard = clay that has been hardened but still moldable to a certain consistency, whether somewhat hard or very hard. This is easiest when attempting to build with slab walls or carve due to its sturdiness. It will not fall over.

• Bone Dry = clay that has been left out to dry, room temperature to the touch, and is ready to be fired. No moisture is left in the clay body, which allows for an ease in firing (moisture in clay = water in clay = air in clay = explosions in the kiln). If the clay is still cool or cold to the touch, it is not bone dry.

• Greenware = clay that has been loaded into the kiln and is ready to be fired. This clay can technically be set in water and reconstituted to be used again. Not yet permanent.

• Bisqueware = clay that has been fired once and is now permanent. 

• Glazeware = clay that has been glazed and has been fired a second time.

Wedging = the act of rolling and kneading the clay on itself to remove air bubbles. Removing the air bubbles from within the clay body eliminates the risk of the clay exploding in the kiln with the heated air (science lesson: when air heats up, it expands!) With air dry clay, the air bubbles are not important for the survival of the clay; however, kneading and wedging makes the clay more dense and will avoid any unexpected holes as you are building. You don't want to start over because you cut through the clay and found a gaping hole, do you?

Coil = the process of rolling the clay in to thin 1/4" - 1/2" noodles. The noodles stack up upon each other to build the structures. When attaching two pieces of clay you need to score with a scratching tool and then add slip... even with air dry clay. It makes it more secure...

Drape = the method of taking a thin sheet of clay, usually thinner than a slab would be, and laying it over top of an object to take its shape. With the drape method, you can use a plaster mold (the best use, as the plaster helps to suck out the moisture from the clay, allowing it be easily lifted off) or another object. If you use an object that has a coating that would stick to the clay, a barrier needs to be put down first (vaseline, paper towel, etc.) so the clay can easily be lifted off the mold.

Slab = using a rolling pin to create a thin wall or sheet of clay to use as a building structure, typically with boxes or flat cylinders. Guide sticks (like paint stirrers) are used on either side as you are rolling with the pin to avoid the clay getting too thin and to keep it even. When you're building with a slab construction, it is best to let the clay get to the leatherhard stage before constructing.

Pinch = using your fingers to manipulate and pinch the clay in to the form you want. Another term for Hand Building because you are simply using your hands rather than an actual technique.

Wheel Thrown = the process of using a pottery wheel to form and mold clay into a cylindrical appearance. The wheel can be used for a variety of purposes: lids, bowls, plates, mugs, cups, vases, or other abstract forms that can start off as a basic form and then distorted on or off the wheel. 

Glaze = an enamel-like and vitreous (glass like in appearance) coating on clay that applies like paint and needs to be fired to the appropriate Cone. Glazes come in all cones, colors, textures, and decorative embellishments and finishes such as crystal, color burst, shimmer, matte, gloss, etc.

• Matte/Shino glaze = rough and buffed texture finish 

• Crackle = applies evenly as a top coat on top of another glaze, but after fired at the proper Cone crackles to reveal the underglaze. 

• Gloss = shiny, glass like glaze

• Color burst, Crystal, Shimmer = specks of crystals in the glaze that burst in explosions of color when heated to the proper Cone

• Underglaze = glaze applied underneath a gloss or a clear coat that is best for decorative elements. Come in liquid and pencil form. When fired, is not glossy or vitreous.

• Clear Gloss = a glaze that applies over top of a finished glaze coat that when fired turns clear. Helps turn underglaze glossy.

Kiln = the oven designed to fire clay to any temperature necessary depending on the clay body or glaze. Kilns come in a variety of forms (electric, gas, brick, raku, salt oven) and purposes (high fire business professional, rustic brick for small business ceramic artists, school grade multi-purpose kilns, etc.)

The tools you will use when creating your slab containers with lids are:

• Needle point tool for detailing and poking vent holes in anything hollow

• Slip

• Scoring tools (forks work just as well)

• Scraping and carving tools

• Rib tools to smooth out sides

• Canvas sheets to work on

• Texture tools (you can literally use anything around the room to add texture... even your own shoe!)

• Tray and Plastic bag for storage

Sometimes a very unorthodox object can be used for a clay tool... think outside the box sometimes!