Ceramics: the process of forming objects out of earthy materials like clay (near bodies of water)
Types of Clay: White Clay, Terracotta, Indian Red Clay, Terracotta, Stoneware or Porcelain.
Wedging: working the clay into a smooth mass to rid it of air pockets
Rolling a slab: flattening clay to a 1/4” thickness (pancake like form)- Never make too thick!
Coiling: forming long, cylindrical pieces of clay by rolling with the fingertips
Score: joining two pieces of clay together by “roughing up” / making incisions on the surface
Slip: a thick clay and water mixture used to “glue” two pieces of clay together
Vent: poking holes into a hollow form (this creates openings for air to escape)
Kiln: a furnace for “baking” or firing clay
Firing: heating the clay to a specific temperature to completely eliminate all the moisture.
Plasticity: the flexibility of clay; how well you can work with the clay without it cracking or breaking (depends on the size of the clay particles and the amount of water in the clay)
STAGES OF CLAY
- Plastic ware–the First state clay when it is very easy to bend and manipulate.
- Leather-hard: The 2nd state of clay, when it has a low level of moisture (about 15%) and is not very pliable, though it can still bend to some extent. May get “stress cracks”.
- Bone Dry : The last state of clay when all moisture is gone and it is no longer possible to work with it. Very Brittle.
Greenware: clay that has not been fired.
Bisque fire: 1st firing of the clay after it is bone dry
Glaze: used to waterproof and add color to clay projects; made from glass, pigments, metals, ores, and other materials.
Glaze Fire: 2nd Firing of the clay so the glaze melts and seals the clay. If done correctly, vessels should be functional- able to drink and eat out of.
Important Clay/Glaze Facts:
1) Clay shrinks as it dries (about 10-15%) Make projects a little bigger than what you want.
2) Clay is recyclable if it hasn’t been fired- DO NOT throw it away!
3) Clay will dissolve and become softer as more water is added
4) Air pockets and moisture left in the clay can cause clay to explode in the kiln.
5) Keep projects moist and always cover them completely with bag so they do not dry out.
6) Clay can be finicky, and 25% students will start over / or change their original idea at some point…. Learning to work with the clay takes patience, so learn as you go ( with a smile).
1) Clay pieces are glazed to strengthen, waterproof and add color to the clay
2) DO NOT glaze the bottom of a clay project ( it will glue itself to the kiln shelf & ruin both!)
3) Shake glaze and stir with stick before applying each color of glaze
4) Apply three coats or layers of glaze to each area of a project. Allow glaze to dry between coats.
5) Dab the glaze onto a project (do not over -brush it)
6) Glaze colors look different in the jar than what they will after they are fired: EX: a glaze labeled as blue may look like pink before firing. It will change to blue & become shiny during the firing.
Overglaze (in large jars): color or pigment that is applied over a bisque fired clay project ( 3 coats)
Underglaze (in small jars): color or pigment that is applied for details ( 3 coats) underneath a CLEAR, shiny top coat glaze ( 3 more coats).
A on the outside of a glaze container = after firing, the piece may be used to eat or drink out of.
Potter’s Wheel/ or Throwing Wheel: a machine that uses a flat, rotating disk where clay is thrown on the surface, rotated and clay pieces are formed
Throwing: Process of creating a ceramic clay project on a Potter’s Wheel
Wire cutter: used to cut clay from a larger block
Fettling or clay knife: used to cut, score or add texture to clay
Loop, wire, ribbon tools: used to scoop clay to hollow a form, trim or add texture to clay
Wood modeling tools: used to join, scrape, shape and add texture to clay
Sponge/brush: used to smooth the clay, usually with water