How do I throw a really
large piece?
It doesnt take that much more effort to throw a large piece.
Get greater leverage by sitting higher on the chair. Avoid
slumping by using clay is slightly dryer than what you use for a
small piece. Come to my workshop on how to throw a 25 pound pot
the easy way.
My glaze has pinholes
after firing. What did I do wrong?
If you havent trimmed carefully, pits can develop in those
areas. Also, reduce the temperature slowly at the end of firing
to allow the glaze to settle smoothly.
What do I do if my
pots always crack?
A: You might be firing your kiln too fast. On the bisque firing,
take the heat up slowly. Also, make sure the pieces have been
carefully dried and that they are bone dry. Uneven clay will
crack. Cover with plastic or partially cover to regulate drying
time. Pay attention to weather. A dry day can dry the pot too
fast and cause it to crack. White clay is especially sensitive
to cracking.
What is bisque ware?
Pots fired to a low temperature (between 950-1050 C, 1750-1950
F, cone 08 to cone 04) and have not been glazed. Bisque pots are
strong but porous. Expected shrinkage has taken place. Glaze is
applied to bisque ware and re-fired for added beauty and
strength.
What is an engobes?
Engobes is a colored slip, or a slip that has been chemically
altered to melt. It is somewhere between a slip and a glaze.
Engobes can be applied under a glaze coat to produce an
underglaze decoration. Engobes are generally applied to
greenware, but formulas developed for less shrinkage may be
applied to bisque ware.
What is greenware?
Pots that have not been fired are called greenware, particularly
when dry enough to load into a kiln. This is the most fragile
stage. The piece has lost all moisture and therefore all
plasticity, but has not gained the strength of a ceramic.
What does
leather-hard mean?
Leather-hard is the stage in drying a pot where the pot will
hold its shape but has not lost all its water. During this stage
you can apply handles or do a variety of other application or
trimming tasks.
What does bone-dry
mean?
This is the final stage of greenware prior to bisque firing. A
bone-dry piece is completely dry.
What is a slip?
A slip is a clay slurry used to decorate pots or stick pieces
together like clay glue. An example of a simple slip is a clay
body mixed in water. Slips are generally applied to greenware,
but formulas developed for less shrinkage may be applied to
bisque ware.
What temperature
should I fire to?
Firing temperature is affected by many factors. Consult the
manufacturer or clay source for detailed information on the
specific clay you are using. The following are some firing
basics:
- Fire earthenware between cone 06 to 02. (Bisque fire to
cone 04, glaze fire to cone 06). [low fire]
- Fire stoneware between cone 5 to 10. [high fire]
- Fire porcelain between cone 10 to 13. [high fire]
- Some stoneware claybodies are fired between cone 6 and
7. [mid fire]
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