a part of the earth
made workable with water
dried by the air
made durable with fire
Clay is the most important
single material used in ceramics. Potteries
first developed alongside river banks where the action of the stream exposed
clay beds. Although we will be
using clay to make pieces of artwork, clay is also used industrially in the
United States to create such items as bricks, building and drainage tiles,
plumbing fixtures (toilets and sinks), electrical insulators, and linings for
steel and glass furnaces.
Seldom can one successfully
use clay just as it is dug from the ground.
Depending upon its origin, clay usually contains large impurities such as
vegetation matter or rocky debris. Although
our clay will come ready-to-use in a plastic bag, it is important to know the
process by which it arrived in this form:
Dig up a lump of clay and let it dry completely.
Pound with a mallet into a coarse powder.
Sift through a ˝ inch mesh screen to remove large pebbles, roots and
Pour the powdered clay into a bucket of water.
Let set until clay has soaked up the water.
Stir occasionally until all lumps disappear.
This may take several days.
Strain the clay through a 14 to 16 mesh sieve.
The clay should be in slip (soupy, watery form) form for this process.
Allow the clay to settle, siphon the water off the top.
Place the clay on plaster bats to absorb excess water.
The process of making
something out of clay can be extremely simple as well as very complicated.
Even thought the clay can take any shape given to it, because of stress,
improper balance of weight, incorrect methods of joining, or improperly
constructed walls, it may not always hold.
Even if you do get a piece
to hold and dry in the desired form, you have to make sure you haven’t sealed
any air inside. All hollow spaces
must have a hole to the outside so air can flow in and out during the firing
process and explosions can be prevented. It
is also extremely important that you don’t make any portion of your work
thicker than ˝”. That dense of a
piece of clay will not be able to withstand the extreme temperature in the kiln
and will explode. All large objects
must be made hollow, with walls no thicker than ˝” and a small hole allowing
passage of air in and out of the hollow space.
There are three common
methods to creating basic constructions: pinch,
coil and slab. To make a pinch
pot, make a small ball of clay the size of a tennis ball or less, and stick
your thumb in the center, making a hole. Then
apply pressure with your fingers on the outside and thumb on the inside,
creating a rounded bowl shape. You
can easily join two of these shapes together to create a spherical form that
could be the body or head of an animal figurine, bird house, etc.
Creating a coil
pot or coil structure is repetitious, slow and tedious, but the results can
be extremely pleasing and original. To
make one, create a coil by carefully rolling a lump of clay with all 8 fingers
so that it is a nice and even thickness. Coil
it upon itself to create the bottom of the pot.
Make another coil of the same thickness and attach it to the end of the
first coil, carefully smoothing them together.
Finish the bottom of the pot if necessary, then allow the coils to go on
top of one another. The closer in
you go, the more the pot will taper in. Putting
the coils more towards the outside will make the pot expand outwards.
You can create some interesting effects by making the coils go in and out
in this manner. If you desire a
smooth look, you can smooth the coils as you go.
You could choose to smooth just the inside and leave the coil appearance
on the outside.
The slab method allows for the most variation of creations.
One can make just about anything out of a slab.
A slab is made by rolling the clay with a rolling pin to an even
thickness. It works best to have
guides of the same thickness that the clay is to be. The
rolling pin rolls over the guides with the clay in between and keeps all the
clay the same thickness, preventing you from pushing too hard with the rolling
If the clay is sticking to
the rolling pin, it is too moist. Work
it into a piece of canvas to get some of the moisture out.
Also make sure that no clay has accumulated on the rolling pin before you
begin. Your clay slab will stick to
When constructing slabs, it
is best to have them slightly dry because moist slabs will not hold up and will
wobble and droop. It is also best
to join clay that is the same consistency to prevent warping and cracking as
they dry at different rates.
When joining slabs, it is
advisable to score the surfaces of the pieces to be joined.
This means to make some scratches in them to roughen them up, making the
surfaces stick together more readily.
Once the main body of the
slab structure is assembled, it can be paddled, shaped, cut into, twisted, or
otherwise formed into the final concept. Other
appendages, handles, spouts, decorative clay forms, wads of clay, coils,
decorations and textures can then be added if desired.
Certain textures are best
applied when the clay is in the soft, plastic state. For example, you can pinch or “flute” the edges of a
piece. You could also pinch small
parts outward over a large area to create a scaly appearance.
Impressed designs can be
made by pressing textured objects into the clay. Objects such as pencil erasers, forks, shells, bottle caps,
fabrics, etc. can be used to create interesting textures and patterns.
The texture should be applied when the clay is soft enough to take an
imprint, yet not so soft as to stick to the texturing device.
Other interesting textures
can be created by carving into leather-hard clay. It is important that the clay has dried partially and is no
longer pliable. This way, you can
make deep cuts and even holes in the surface that won’t affect the stability
of the piece. You can use a
paperclip loop to scoop out clay and make unique textures.
The clay must dry for
several days before firing in the kiln. If
it is too moist, it will explode. The
kiln heats the clay pieces to a temperature of about 1870 degrees Fahrenheit for
about 3 ˝ hours. This makes the
clay durable and fuses small appendages to the main construction more
permanently. Because the molecules
of clay will become more compacted, your final project will be about 90% of the
size it was before it went in. You
will now be able to touch small pieces and use handles without worry of damage.
If you want your clay piece
to be protected from water, you will want to apply a glaze.
This is a mixture that contains small pieces of glass that when heated,
the glass crystals to melt and fuse together, forming a glassy coating.
Any depressions in the clay from the textures you created will have a
deeper color because the molten glass will settle in these areas.
You will paint 2-3 coats of
it on your piece and then it will be fired again. The color of the glaze is rarely the color it will be once it
is fired. Make sure not to paint
any glaze on the bottom of your piece or you risk having it stick to the kiln
shelf. The only way of removal is
destroying the piece.
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