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CHAPTER
4
LETS TALK ABOUT CLAY
WHERE
TO GET CLAY:
Of course you can go dig some up out of the ground! Not me! That’s a
lot of work and I don’t know enough about it. I guess I could if I had
the time and the knowledge about what to look for, and then the strong
back to dig it up, dry it out, sift it, and then mix it properly.
Clay comes either moist or dry. Dry, you have to mix and all kinds of
other thing. Professional potters, who use a lot of clay and have the
equipment to mix it properly sometimes use dry powdered clay. Me, I use
moist clay ready to use. It usually comes in 25 pound bags.
If you don’t already know someone who does clay, let your fingers do
the walking in the yellow pages of the phone book. Look under clay,
ceramics, pottery, craft store(supply) and ask for ideas! You are
looking for pottery clay. If you don’t have any luck, call the local
college art teacher (if pottery or sculpture is offered at the local
college then check the college book store), or art teachers at your
local elementary, middle, or high school, pottery is a course that is
offered at a lot of schools. If all else fails the check the 1-800
phone number directory and ask for numbers of pottery suppliers (you
can get clay delivered right to your door). If you are on-line you can
always find a pottery there.
DON’T BE SCARED!
The worst they can say
is they don’t know!
Keep asking.
WHAT
YOU NEED TO KNOW ABOUT CLAY:
OK now you have found a place to buy clay, I pay about $9.00 per bag
when I buy a single bag. One bag should get you started.
Before you purchase clay, there are going to be a lot of decisions you
need to make. YUCK, you
thought it was going to be easy form here on out, well here I go again.
I’m going to give you some simple explanations that no one gave me and
I had to figure out my self with a lot of questions.
First, clay comes in many colors from white to gray to
brown to red and many different firing temperatures. Lets start with
firing temperatures because it is the most important thing.
TEMPERATURE
OF
CLAY:
You will have to know the temperature you
are going to fire at because that’s one of the ways clay is sold. A
scale known as CONE is used to make it more complicated. All a CONE is,
is small long pyramid shaped piece of clay and glaze (mixed) that will
bend then melt at very precise temperatures. When firing your piece in
a kiln, a CONE is put in the kiln (high temperature oven) to tell when
the correct temperature is reached. Some kilns have a cone holder that
shuts the kiln off when it bends, some have computers, and some you put
the cones directly in (stuck in a piece of clay), place it in front of
a peep hole and manually shut off the kiln when the cone melts.
When you go to buy your clay, you will be asked what cone you want to
fire to. If you have already found a place to fire, ask the operator of
the kiln what cone temperature clay to buy. If you haven’t found a
place to fire, I would advise getting clay that would be cone 04 to 02.
Most places with kilns always go this high. Don’t worry we will go into
firing later.
COLOR/KIND OF CLAY:
Clay color is determined by different
kinds of minerals are used to make up the clay. Also the temperature
that the clay is fired to. Here are the basic kind of clay.
Natural clay - This is clay that has
been dug up form the earth, cleaned and then is ready to use.
Earthenware. This is a mixture of different kinds of clay,
minerals and organic matter such as iron and. This clay is porous and
may not hold water. Unglazed it is known as terra-cotta. It fires at a
moderate temperature and accepts glazes well. It’s colors after firing
range for cream to red to dark brown. This is a great clay for
beginners because it is very forgiving and easy to work with.
Stoneware. This is also a mixture of different kinds of clay
but this one is fired at much higher temperatures. It is not porous and
will hold water, because it has a much tighter chemical bonding. It is
very plastic and is easy to work with, also it is much harder than
earthenware. It will not chip and break as easily after firing. This
clay is what a lot of dishes and kitchen ware is made from. Stoneware
comes in a verity of colors form white to gray to buff.
Porcelain. The main ingredient of porcelain is china clay
(decomposed granite). A very fine clay that is hard to work with and is
not very plastic. Porcelain is translucent when made very thin. True
porcelain is only fired one time. The glaze is put on the bone dry clay
and the clay and glaze are fired at one time to create fusion between
the clay and the glaze. Fine china is made from porcelain. I don’t
advise a beginner to use it, but later on when you get some experience
under your belt it is fun to try a little.
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