2. What is clay?
A fine-grained, firm
earthy material that is
plastic (malleable)
when wet and hardens
when heated.
It is used to make
ceramic art.
3. Brief History of Ceramics
The earliest piece of pottery,
Venus of Dolni Vestonice, dates
between 29,000 and 25,000 BC.
Found in an area of what is now
the Czech Republic.
Chinese pottery dates back to
10,000 BC.
Between 6000 and 4000 BC the
potter's wheel was invented in
Mesopotamia.
4. Types of Clay
Earthenware - the most commonly found clay
in nature and is the raw material usually used
to make most of the pottery in the world.
Stoneware - clays are named this because
when fired they have the characteristics of
stone, which is a hard, dense surface
sometimes with a variegated grayish brown
color.
Porcelain - the product of different techniques
of many early Chinese pottery workers. Its
main ingredient is kaolin, also know as china
clay.
5. Boxwood tools -
Tools
provide enough
texture and sharpness
to shape clay properly
Wire Clay Cutter - useful in cutting large lumps of clay. without causing deep
gouges or other
problems with the
clay.
Needle - one of the
most versatile tools in
pottery - just a few of
their uses are for
scoring slabs and coils
when hand building.
Brushes - used to carry
water and slip to
specific areas when you
are working the clay, as
Loop, Ribbon, and Wire Tools - handy for trimming well as used to paint
greenware. and design with slips,
underglazes, and
Ribs - can help shape and smooth pots.
overglazes.
6. Techniques - Wedging
Kneading clay to
distributing the
moisture evenly,
eliminate hard
spots in the clay,
and force out air
bubbles.
Properly wedged
clay is very
smooth, with an
even texture.
7. Techniques - Score and Slip
To score clay, you hatch small
groves/lines into the edges of the
piece.
A slip is a suspension in water of
clay and/or other materials used in
the production of ceramic ware.
In order to attach two wet pieces
of clay, you have to score both
sides with a needle tool and then
apply slip and mush them together.
8. Heating Finished Pieces
Kiln - A special oven used for firing clay.
Fire - Means to heat the clay in the kiln.
There are two rounds of firing:
Bisque Firing - the initial round of
firing that hardens the clay (16-18
hours).
Glaze Firing - the firing that is done
after coating the hardened clay
with clear or colored glazes.
9. States of Drying
Plastic - Clay in its moist state.
Leather-Hard - Clay that is rigid, but not yet dry.
Greenware - Unfired clay.
Bone Dry - Clay objects which have completely
dried after firing.
Bisque-ware - pottery that has been fired but not
yet glazed.
10. Decorating Your Work
Glaze is a glassy coating
on pottery, the primary
purposes of which are
decoration and
protection.
One important use of
glaze is to render porous
pottery vessels
impermeable to water
and other liquids.
