CERAMICS BASICSWhat you must know before you touch the clay.

Name That Clay Red and white

earthenware clay Earthenware – opaque,

porous, low-fire clay Fired to Cone 05 or 06 Will not be waterproof

unless glazed Red Earthenware also

known as “Terra Cotta”

Greenware

Name That Clay: A Timeline

Wet Clay Leather Hard Bone Dry Fire

BisquewareGlazeFireGlazeware

Step #1 ALWAYS Wedge Wedging – the process of throwing clay onto a

hard surface repeatedly at different angles in order to remove air bubbles and promote malleability (the flexibility/workability of the clay

Always wedge for at least two minutes For stubborn pieces or putting pieces back

together, use the “slice and slap” method (at least 20 cuts)

Works best on a plaster wedging board or other moisture loving surface

The idea…

Tools: Slip The “glue” used in ceramics while a piece is

still in its green state Essentially watered down clay or liquid clay Must be used whenever joining clay

together Also can be used to cast a mold or decorate

a piece Use same slip type as clay Tip: Best slip? Just add white

vinegar!

Tools: Premade and You-made

Tools: Throwing

Methods: Hand-Building Pinch Forming

Methods: Hand-Building Coil-Building

Methods: Hand-Building Slab-Building

Methods: Hand-Building Drape or Push

Molding

Methods: Wheel-Throwing

Rules to Avoid Disaster Always score and slip when adding pieces of clay

together Try to add a coil to your seam when appropriate to

strengthen that seam Always wedge thoroughly Always provide an opening for air to escape a hollow

piece (or a hollow area of a piece) Never exceed ½” in width (if you do, alert Mrs. Roberts) Never touch bone dry pieces except when loading them

into the kiln Always cover your piece in damp paper towels and plastic

bags before leaving for the day Never ever ever put plaster in the kiln No adhesives in the kiln

Rules to Avoid Class Ruin Always dump sludge buckets outside

(never in the sink!) Always wash tools, and always wash them

in the sludge bucket (not the sink, unless all clay has been removed)

Always rinse hands in sludge bucket before washing them in the sink

Never throw clay. Ever. Always wedge your leftover when you are

done

The Kiln “Oven” for clay Cone 05 = 1886 deg Electric Sitter Kiln

2 hours on low (lid propped)

2 hours on medium (lid propped)

Finish out on high until Cone 05 is reached (lid shut)

Pyrometric bar melts at Cone 05 and breaks the circuit

“Ramping” – act of turning up the heat in the kiln

Why me? WHY?!?!? Most kiln accidents are avoidable

The Root of Explosions: Moisture “States of Matter”: Gasses take up more

room than liquids Expansion of water becoming steam

causes destruction

Reducing your chance of incident? Allow your piece to dry uncovered at

least one week before being fired Keep it thin: It dries faster this way,

also the core actually dries Wedge like a maniac: No air bubbled =

no big steam pockets No grenades: Always poke holes into

hollow pieces as a steam outlet

Keeping It Holy Does not have to be large opening – a

pin prick will do(Cross sections)

“It don’ won’ stick!” Score and slip all attachments Scoring – The act of applying a

texture to the surface of clay for the purpose of adhering two clay bodies together

Kiln will successfully remove all attachments if not scored and slipped

Score both piece attaching and attachment point

Finishing: Glaze “Paint” of ceramics Cannot be mixed to create new colors Finish created by a series of chemical reactions

catalyzed by heat When raw, is powdery, matte, and usually not

end color DO NOT GLAZE THE BOTTOM OF YOUR PIECES! Clear glaze can be used to enhance the

intensity of intricate design work 2 to 3 coats; Mix well!

Finishing: Underglaze Matte finish Colors stay true Can be mixed to create new colors Great for detail painting Must be fired before clear glaze can

be applied