Download Clay is decomposed granite

Clay is decomposed granite
Primary clay
• Primary clay is relatively rare. It is clay that is
found at the same place the rock broke down.
• Very white in color
Secondary clay
• secondary clays have
been transported by
wind, water or both
from their places of
formation.
buff, brown, or red
color
Earthenware
• Low-fired ware,
usually still
porous after
firing—must be
sealed with
glaze to be
functional.
Stoneware
• literally as hard and
durable as stone.
• Used for plates and
mugs
Porcelain
• Porcelain can informally
be referred to as "china"
or "fine china” as
China was the birthplace
of porcelain makin. 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.
Paper clay
• Uses a claybody or
slip containing paper
pulp, which reduces
shrinkage in drying
stage, and is easy to
join pieces together.
• Very strong and easy
to work with.
STAGES OF CLAY
• Plasticity(noun):refer
s to how flexible a
clay or clay body is.
Any particular clay's
plasticity is greatly
influenced by the
clay's particle size,
water content, and
aging.
Leather hard
• Leather-hard
(adjective) At this
stage, the clay is still
visibly damp (usually a
darkish gray) but has
dried enough to be
able to be handled
without deformation.
The clay is able to be
carved without
breaking, but will not
receive impressions.
Greenware- period when the clay
is completely dry
Bisqueware
• 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.
• The clay has been painted with a glass-based
paint (called Glaze) and has been fired again...
this is what makes the glaze paint so shiny!.
HANDFORMING TECHNIQUES
• Pinch
• The process of
starting with a ball of
clay, inserting your
thumb and
"pinching" the clay
between your thumb
and fingers,
gradually expanding
and shaping the wall
into a bowl-like form.
coil
• Coil pots are made
when clay is rolled
into thin snake-like
ropes and then
layered on top of one
another. Often times
the outside and
inside of the pots are
smoothed so the
coils are not obvious
slab
• Using thin sheets of
clay to build a
structure, the sheets
can be either rolled
or stretched out.
Press pot
• A form is used for
support and shaping of
the clay. Soft slabs are
draped on top or
slumped inside and
allowed to get
leatherhard and then
built upon or cut and
shaped further. Clay can
be pressed into plaster
molds with a design
carved or cast into a
negative space and then
popped out and
attached.
Wheel throwing
• Putting
clay in the
center of
an
electric
wheel to
form the
pottery.
• Kiln –clay oven
• A furnace made of
refractory (nonmelting) materials
constructed to fire
clay. They are usually
fueled by electricity,
gas or wood, but may
also be fired using
coal, oil, manure or
even old tires.
• Cone
• A pyrometric cone is a
triangular shaped piece of
ceramic materials carefully
formulated to melt at a
specific temperature. They
are placed in the kiln to
monitor and determine
kiln temperature. However,
we use a computerized
cone. So, for us the cone is
the temperature at which
the clay is fired.
• Stamp
• Any device that can
be pressed or rolled
into clay to create an
imprinted design. It
can be made of clay,
plaster, wood or a
found object
• Sprigging
• The technique of
adding an
appendage or
decorative element
to the surface of the
work using coils,
stamps, molds or
free-form design
Glaze
• A mixture of powdered
ceramic materials
clay, glass, fluxes and
colorants in suspension
with water. It is applied to
bisqeware and then refired to a higher
temperature (usually).
Glaze is used to decorate,
protect and make the ware
food-safe. Do Not apply
glaze to the bottom surface
of the work or the any part
that may rest upon or touch
the kiln shelf.
• 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
• Slaking:
• Adding water
to dried up
clay to make
it plastic
again.
Grog- pieces of brick or sand
added to clay to make it strong
• Wedging-pounding
of the clay over and
over to get rid of air
bubbles
Air bubbles?
• If your clay has air
bubbles the clay
could explode.
• Water gets trapped
in the air bubbles.
The water begins to
steam and the steam
explodes the clay.
• CANDLING:
• When you preheat
the clay for 24 hours
to 180 degrees to
release water gently.
• Almost totally
reduces the threat of
blowing up the clay.
Phases of Firing
• Preheat (candling)180 degrees
• 428 degrees-initial
breakdown of plant
materials in clay.
(smelly time).
• 572- 1292 degreesrelease of chemical
water.
http://www.youtube.com/watch?v=mww6X
OYYhtA
• Chemical water has a
strong electrical
charge that binds it
to other molecules
that may be attached
to it.