Ceramics Basic Vocabulary
5 Stages of Clay Wet /slip Leather-hard Bone dry/ Greenware Soft Leather-hard stage this is the time to make repairs clay is stiff enough to hold its shape, but can still be GENTLY bent Hard Leather-hard stage clay will crack if bent perfect for carving Bone dry/ Greenware Clay is very fragile in this stage Bisque (1st Fire) Clay undergoes chemical change & is now CERAMIC Glaze fired
Slip vs. Glaze Slip is watered-down clay Used as a “glue” when joining pieces Also used as a decorative element or surface treatment Apply slip BEFORE firing A more complex chemical combination When fired, becomes a thin layer of glass Apply AFTER bisque fire Pay attention to labels on glaze! Dinnerware safe? Correct cone?
Cone firing range
Differences in clay Types of clay we use: Shrinkage rates White earthenware Red earthenware Raku Stoneware Porcelain Shrinkage rates Firing temperatures yes, clay will melt if fired too high!
Wedging Clay Kneading the clay Removes air bubbles Thoroughly mixes clay
“Scratch & Slurry” Scratch both parts to be joined Apply slip (slurry) or water to scratched areas and press together Smooth a coil into the joint for extra strength
Drape Mold Select item to be used for mold Be sure to cover w/cloth or paper! Roll out slab & drape over or into mold Be mindful of the shape of the mold Undercuts will make it difficult or impossible to remove the mold without damage Will the clay crack as it shrinks in/on the mold?
Things to do to avoid confusion, the ruin of your work, and the annoyance of the teacher ALWAYS sign your work When your work is ready to fire, put it in the appropriate area Clean up after yourself, including the sink area, bats, boards, tools, table, etc.