Tom's E-mail on thu 2 jan 03
I would ask Howard but he's out of town. I'm interested in exploring an =
idea I have with thixotropic clay that fires in the cone 5-6 range. Is =
there an easy way to make one's clay thixotropic? If so how? If not does =
anyone know where such can be obtained. I previously sent a similar =
message but am uncertain if it got thru. Thanks in advance
Tom Sawyer
tsawyer@cfl.rr.com
Millie Carpenter on thu 2 jan 03
Tom
Ceramics by Nelson has a good recipe for thixotropic clay and a
corresponding recipe for glaze. thise are for ^5 and another body only
for ^9. If you don't have the book, I will type it in for you.
Millie in Md
millie@riva.net
Tom's E-mail wrote:
>I would ask Howard but he's out of town. I'm interested in exploring an idea I have with thixotropic clay that fires in the cone 5-6 range. Is there an easy way to make one's clay thixotropic? If so how? If not does anyone know where such can be obtained. I previously sent a similar message but am uncertain if it got thru. Thanks in advance
>Tom Sawyer
>tsawyer@cfl.rr.com
>
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Gail Dapogny on thu 2 jan 03
You should consult an expert, but I seem to remember that a little
bentonite promotes that phenomenon. It might be Vince who said that. Also
check Hamer.
----Gail
>I would ask Howard but he's out of town. I'm interested in exploring an
>idea I have with thixotropic clay that fires in the cone 5-6 range. Is
>there an easy way to make one's clay thixotropic? If so how? If not does
>anyone know where such can be obtained. I previously sent a similar
>message but am uncertain if it got thru. Thanks in advance
>Tom Sawyer
>tsawyer@cfl.rr.com
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
http://www.silverhawk.com/ex99/dapogny (single historical photo - no longer
registered with Silverhawk)
Dannon Rhudy on thu 2 jan 03
Tom asked:
........I would ask Howard but he's out of town. I'm interested in exploring
an idea I have with thixotropic clay that fires in the cone 5-6
range..........
Look on page 175 of the Nelson/Burkett book "Ceramics,
a Potter's Handbook". That's the re-issue of Glenn Nelson's
book. Also, there is a longer section in Nelson's own earlier book,
on thixotrophy. Whole chapter, I think. It is not greatly
difficult to make a thixotrophic body.
regards
Dannon Rhudy
Vince Pitelka on mon 6 jan 03
> I would ask Howard but he's out of town. I'm interested in exploring an
> idea I have with thixotropic clay that fires in the cone 5-6 range. Is
> there an easy way to make one's clay thixotropic? If so how? If not does
> anyone know where such can be obtained. I previously sent a similar
> message but am uncertain if it got thru. Thanks in advance
Tom -
A friend noted that no one responded to your request, so I'll have a shot at
it. I have always avoided thixotropic clays at all costs, because I can't
imagine what they are good for except making those "stretched taffy"
sculptural forms that were popular about 30 years ago. Ick.
In my experience, a deflocculated gritless claybody will be thixotropic.
There may be other conditions for ideal thixotropy, and you might go back a
few decades in CM for articles about thixotropic claybodies. If you want to
do some tests, mix up a gritless claybody with 1/2 of 1% (of the dry
materials weight) each of soda ash and sodium silicate (dissolved in hot
water that is then used in the claybody). Most of the thixotropic
claybodies used for those gooey "Attack of the Blob from Space" sculptures
were whiteware or porcelain bodies, but I cannot imagine why whiteware would
necessarily be more appropriate for thixotropy.
If you want to achieve thixotropy with an existing plastic clay, I would
weigh the clay, deduct 25% of the weight (water content), and figure the
soda ash and sodium silicate additions on this estimation of the dry
materials weight. Add the deflocculants to a small amount of boiling water
and stir to dissolve. Obviously the sodium silicate will dissolve
immediately, since it is already liquid. If the soda ash does not dissolve
completely, add a little more boiling water, and keep doing this until the
liquid is clear. Poke a lot of finger holes in your plastic clay, and pour
in the mixture. Leave it for a day or so until it absorbs into the clay,
and then wedge very thoroughly.
As you probably know, thixotropic clays characteristically get very stiff
when left undisturbed for a few days or so, but when you move the clay
around by wedging or slamming it, the clay will usually become stretchy and
gooey, often to a very messy degree. Sounds like fun, eh?
Experiment away, and let us know what you come up with, technically and
aesthetically.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://iweb.tntech.edu/wpitelka/
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