Transcript CERAMICS - Pearl Quick

CERAMICS
CLAY SLAB
Container
Bug theme
Candy theme
Flower theme
Bait theme
Pyramid theme
CLAY
 Mud; moist, sticky dirt.
 In ceramics, clay is finegrained,firm earthy material that is
plastic when wet, brittle when dry,
and very hard when heated.
The most common types of
ceramic clays are:
 earthenware,
 stoneware, and
 porcelain.
Earthenware
 Earthenware is a low-fire clay that
is porous and not waterproof.
 It can be made waterproof by
glazing it.
 You will use earthenware clay to
roll out a slab and create a ceramic
container.
Clay Slab Plan
 First plan on newsprint.
 What will be your theme…Nature or
man-made?
 What shape expresses your theme?
 What decoration helps express the
theme?
 Does the container need additions…
“feet”, handles, top, lid, pictures?
Clay Slab Plan
 Roll out a slab of clay
 Cut the sides, then bottom & top
Clay Slab
 REMEMBER when measuring,
clay has thickness.
Decide how the sides will overlap and how
thick the slabs will be before figuring the
size of the bottom of the slab piece.
For example:
or
When the slabs are rolled out, and
they are cut to size, they should be
allowed to dry to the leather-hard
stage before assembling .
Leather-hard
This is the first stage of drying. There
is still moisture in the clay, but it is
just dry enough to hold its shape
and not “slump” This stage of
drying is called leather-hard.
When the slabs are leather hard,
they can be assembled by
scoring (scratching) and
slipping the edges to be joined.
 What is scoring and slipping????
Score the clay that is to be joined
Make
scratches in
the pieces of
clay to be
joined
together.
Roughen the
surface.
Add clay slip to the scored pieces
to join them together.
 Clay slip is a fine,
liquid form of clay
used to cement
together parts that
have been formed
separately. Mixing
finely ground clay
with water makes
clay slip.
The scratched and
slipped edges should
be pressed firmly
together and the joints
blended with a finger
tip or a small tool.
Square corners should be given
additional support on the
inside. Make a coil the size of
an earthworm, lay it carefully
in the inside corner and
smooth it into each side of the
corner.
Bone Dry
 When finished, your greenware
container needs to be thoroughly
dry before it can be fired.
 This stage of drying is called
bone dry.
Greenware Unfired clay is
called
Green ware
Bisque
 Fired clay is
called
Bisque ware
Firing
 Clay is hardened by heating it to a
high temperature, thus fusing the
clay particles. Temperature in kilns
can reach 2500 degrees.
Glaze
 The bisque clay container is now
ready to be glazed.
 Glaze is a coating of material
applied to ceramics that forms a
glass-like surface when fired a
second time.