Ceramics
The word ceramic, derives its name from the
Greek keramos, meaning "pottery", which in
turn is derived from an older Sanskrit root,
meaning "to burn". The Greeks used the term
to mean "burnt stuff" or "burned earth".
What is Clay?
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Clay
particles of decomposed rock combined with water
to create a plastic, malleable body which is then
fired in a kiln to fuse the particles back into a stonelike state.
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Clay is made up of Silica,
Aluminum Oxides, and
water.
Generally Clay is formed
by the chemical
weathering of silicatebearing rocks by carbonic
acids.
Clay particles are
distinguished from other
particles in soil by their
small size, plasticity, and
affinity for water.
Cultures
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Archaeologists have uncovered
human-made ceramics that
date back to at least 24,000
BC. These ceramics were
found in what was formerly
Czechoslovakia and were in
the form of animal and human
figurines.
The first use of functional
pottery vessels is thought to
be in 9,000 BC. These vessels
were most likely used to hold
and store grain and other
foods
Uses
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Most people, when they hear the word
ceramics, think of art, dinnerware,
pottery, tiles, brick and toilets. The
above mentioned products are
commonly referred to as traditional or
silicate-based ceramics.
What most people aren't aware of
is how diverse ceramic materials
really are. They can be used for
almost anything. Ceramics are
currently used for computers,
tools, dental replacements,
engine parts and tiles on space
shuttles. Ceramics play an
important role in our everyday
lives, even the parts we can't see
and don't give much thought to.
Types of Clay
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Earthenware -A low-fire porous
body, usually red or orange-tan
in color due to the impurities and
presence of iron. It is the most
widely available type worldwide.
Types of clay
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Stoneware -A high temperature,
strong, vitreous body, usually graybrown in color. It is the most
popular clay for utilitarian wares.
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Types of Clay
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Porcelain- The highest
temperature as well
and most
temperamental clay
body. It is the purest
form of clay possible,
it is white and has
translucent
capabilities.
Greenware

Greenware is a
term used to
describe clay that
has not been fired
yet.
Stages of Clay
Clay mixed with water, until it is like mud
is called Slip
 When clay is soft and pliable it is called
Plastic.
 When the clay is still workable on the
surface it is called Leather Hard.
 Bone Dry is the stage at which the clay is
completely dry, fragile, and is ready to be
fired.
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Slip -A thick and creamy mixture of clay
and water used to join clay parts together
or to decorate the surface. It is applied
before firing, when the clay is still wet.
 Plastic-Clay that is soft, pliable and easy to
work with.
 Leatherhard-Clay that has been allowed to
dry slightly, making it stiffer and able to
support its weight, but can still be worked
on and have parts attached.
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Bone Dry-The state of clay when all
naturally occurring water has evaporated.
The clay is hard, dry, with a chalk like
consistency.
Kiln
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When the clay is Bone
Dry it is ready for its first
firing which subjects the
clay to high temperatures
and causes a chemical
reaction.
A fireplace or oven
specifically designed for
hardening clay is called a
Kiln.
Kilns come in all sizes and
shapes from wood fired
pits dug in the ground to
computerized containers
like the one on the left.
Bisque-The first firing for the clay,
removes all of the water, (both actual and
chemical) and carbon, The fusing of the
particles has begun, yet the clay is still
porous to allow for glaze absorption. It can
no longer be slaked down and recycled.
 Glazeware-The second firing of the clay
with a coating of glaze upon its surface, it
is fired to a higher temperature than
bisque and therefore fuses the particles
into a solid, non-porous state called
vitrtification.
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Until the clay has been fired it is possible
to RECYCLE the hardened clay so it can be
reused.
 All clay used in class should be recycled if
it is not going to be fired.
 DO NOT THROW CLAY INTO GARBAGE
CANS!
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Bisque
Bisque is the term
given to the first firing
of clay.
 Cones (left) are used
to determine what
temperature the clay
is fired at.
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Pyrometric cone
chart
06
1798°F
05-1/2
1839°F
05
1870°F
04
1915°F
03
1960°F
02
1972°F
01
1999°F
1
2028°F
2
2034°F
3
2039°F
4
2086°F
5
2118°F
5-1/2
2133°F
6
2165°F
7
2194°F
8
2212°F
9
2235°F
10
2284°F
Glaze
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Glaze is a powdery material
that is coated on Ceramics and
then fired to form a thin glass
like coating.
Glazing not only creates an
aesthetic smooth, surface but
also strengthens the piece and
allows it to hold liquid.
It is possible to enhance the
surface of the clay through the
use of glazes and under
glazes.
HAZARDS
Clay Dust can be hazardous if inhaled over
a long period of time.
 Although students are at minimal risk due
to the limited exposure, care should be
taken to minimize dust in the classroom.
 Clean all tables and tools with wet
sponges, and dispose of dried clay
properly. (recycle bucket)
 NEVER sand pots in the classroom.
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