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Lesson Plans

Re: Seaking expert ceramic advice

[ Thread ][ Subject ][ Author ][ Date ]
Numo Jaeger & Michael Miller (jaegmil)
Mon, 01 Feb 1999 18:37:52 +0000

Did you preheat the tiles in the kiln for at least 4 hours before you
turned the kiln on? Some of the digital setting on the kilns are to fast a
firing schedule.

Does your kiln have a ramping system? If so, set the ramping system so that
it stays below the boiling temperature of water for a few hours and then
time it so that it passes through the boiling temperature slowly.

One of the main reasons for failure in firing pieces in a kiln is that
there is water in the clay body. The pieces need to be bone dry before they
are fired.

For a the initial firing called the bisque or bisquit firing you shouldn't
raise the temperature any faster than 200 degrees F per hour.

Numo Jaeger
Ceramics Department
Studio One Art Center
Oakland CA

At 10:28 PM 2/1/99 +0200, Lisa Teske wrote:
>I am a real novice in ceramics, and a world away from understanding
>mamaging a kiln. I would really appreaciate some advice.
>I have started this year in Egypt with an old kiln that was made digital
>over the summer. I test fired glaze test tiles successfully at 1100
>degrees C.
>Then I fired my 8th grade ceramic tile mural at the same temperature, and
>only 1/3 of the tiles survived. The rest of the tiles broke into bits as
>small as sand to as big as a quarter. I am not sure what happend, but I
>am terrified to fire my high school pieces until I figure it out.
>Do you think that it is from impurities in the clay? It was bought on the
>local Egyptian market. It has little bits of plaster and some other type
>of rock in it that the students picked out carefully while wedging and
>incising their pieces.
>Or did I fire at the wrong temperature?
>Any suggestions would be terrific. I want to make sure it is the clay
>before I through the rest of the barrel out.
> Lisa Teske, art teacher
>Schutz American School * P.O. Box 1000 * Alexandria, Egypt 21111
>lisa *