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Lesson Plans

recycle clay (longish)

[ Thread ][ Subject ][ Author ][ Date ]
Marvin P Bartel (marvinpb)
Thu, 6 May 1999 21:32:33 -0500

I applaud those of you have found efficient ways to reprocess dry clay. I
agree that unless you can get the students to do the labor it may not really
be worth the teacher's time. Here are a few thoughts on the matter from a
ceramics teacher who has now has a clay mixing machine, but there was a time
when we did it all by hand in university ceramics classes I taught.

1. It teaches values. Students learn the joy of being thrifty, useful,
productive, and helpful.
2. For some, it offers a chance to earn the teacher's approval and friendship.

3. Physical work builds muscles and conditions the body.

4. Physical labor is a stress reliever.

5. Waste not, want not.

1. Totally dry clay, not matter how thick, will turn to mush overnight in
clear water. Any water proof container works. Set the clay in and add clear
water. Or, place dry clay pieces in clear water. Do not stir it before it is
all mush, because slip clogs the pours of the dry clay. No need to stir it
at all unless you need pour it through a screen it to clean trash out of it.
Screening the slip through common fly screen is needed for most clay that
you dig yourself, but not needed for rework clay.

2. Leatherhard clay chunks do not soak readily because it is not porous. Let
leatherhard clay dry out before soaking it. No need to break it up if you
can wait for it to dry.

3. Once the clay is mush with clear water on top, remove the water to
another container or discard if it is free of clay. The remaining thicker
mush in the bottom of the container can simply be left, but it takes a long
time to dry enough to use.

4. To speed the drying, it needs to be on absorbent material. While plaster
is often used for this, I don't like it much because the chips of plaster
will pop out of the clay projects after firing. To safeguard against plaster
contamination, use a layer of cloth or canvas. Cloth lined wood slat
containers setting on blocks on window sills, radiators, or elsewhere allow
air to dry out the clay from all directions at once. It helps to set up a
fan on it overnight. No plaster is needed.

5. When it gets almost dry enough, wedge it just a bit and seal it in
plastic bags or cans for future use. I double bag it if I plan to keep it
moist more than a few months.

1. Some teachers have students add dry clay dust and wedge it in order to
thicken the mush. If this makes any dust in the air, it is not a safe
practice unless everybody in the area wears good quality approved
respirators. Clay is not a poison, but the dust does reduce lung function
over time. Clay workers have died from silicosis which disables the lungs
capacity to oxygenate the blood. For the same reason, I do not allow
students to sand their clay projects. All smoothing should be done as wet
processes. Persons who sanded artclay pieces in factories to remove mold
marks are the ones who died - sometimes after two years on the job.

2. Bacteria in clay is good for plasticity. Dead bacteria lubricates the
particles. It is in all moist clay. It often includes harmful bacteria.
There are animal and bird droppings in and around clay mines. I have never
known of anybody getting ill from it, but I advise students to keep it out
of their mouth and to wash their hands well before eating.

3. Molds are everywhere, and I don't mean those omnipresent hobby shop
plaster molds. I mean the fungi mold in the air and especially in aging
clay. People vary a great deal in their sensitivity and allergic responses
to molds. If you are a teacher who is highly sensitive, you may have to
forgo all of this. It helps to keep it in closed containers so the artroom
air doesn't get contaminated. It helps to dry it and store it away from the
classroom where you spend your time. In some climates or in warm seasons,
dry it outside under the protection of a porch or make shelves with a little
tin roof in a non conspicuous place behind the school.

Several years ago at the National Council on Education in Ceramic Arts
(NCECA) meeting a California high school teacher told about having his class
out foot mixing all the clay for the year on a warm day in September in the
school parking lot. Plastic wading pools were used for students to rinse
their feet before and after getting into the mix. Put out dry clay, add
rework mush, add water if needed, stomp till done, bag it up.

Best regards,
Marvin Bartel

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