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Re: Turning hard clay into usable clay


From: Marvin P Bartel (marvinpb_at_TeacherArtExchange)
Date: Mon Mar 04 2002 - 07:41:21 PST

At 05:37 AM 3/4/02 -0800, you wrote:
>I have a large amount of hard clay leftover from the previous art teacher.
> What is the best way to rejuvinate it to make it usable?

Here is my SIX STEP PROCESS to rework the old clay.

1. Clay must be totally dry. There is no need to break up dry clay.
Be sure it has no plaster chips in it - plaster causes pop-outs when bisque
fired. Leather hard clay or moist clay does not slake well because it is
not porous like dry clay is. Instruct students to handle the dry clay
without making dust. A lot of airborne dust is not healthy to breath (see
web page below).

2. Flood clay with clear water (or drop it into water) in something like
garbage cans. Use enough water so clay is totally under water.

3. Never stir it. Stirring stops up the porosity and prevents good
slaking (soaking to mush).

4. In a few days, even huge chunks of dry clay will slake to mush.

5. When it has turned to mush, remove extra water from top. Dip water off
or siphon it off.

6. You can stiffen the mush by allowing it to set for many months with the
lid off.
To dry it faster, spread the mush a few inches thick on clean dry porous
surfaces. I use, dry plaster, clean concrete, canvas, denim, etc. Smooth
the top to avoid getting small dry pieces on the surface. The breeze from
a fan at night helps and/or place it where air from a heat register hits it
(do not block the air flow). When it is nearly dry enough, I make coils as
thick as my arm and set them around like big arches (a foot tall) and they
are ready to wedge and use in 24 hours or less. This clay can be stored
forever in an airtight plastic. In ancient China, potters stored moist
clay in caves for the next generation to improve the plasticity of the
clay. If it is to be stored long-term, double wrap it. Double wrapping in
plastic bags from the supermarket works. Students can bring in hundreds of

For me, teaching art includes teaching students to how to rework clay.

This is a web page about safely working with clay.

This is a web page about safely cleaning up in a clay studio or classroom.

Marvin Bartel