Vince Pitelka on sun 26 may 96
Emily -
Experiments in Khazueland aside, native peoples from around the world have used
crushed seashells for tempering material in claybodies used in bonfiring. At
the relatively low temperatures of the bonfire the crushed seashell just acts
primarily as an inert grog, opening the clay and giving high thermal shock
resistance. I don't ever bonfire with the wares in direct contact with the
flames, but there are certainly many cultures historical and contemporary that
do, and having sufficient tempering material (often up to 50%) is essential for
the needed thermal shock resistance. Regarding what the Khazue would do in
this situation, I haven't made up that part yet.
- Vince
Vince Pitelka - wkp0067@tntech.edu
Appalachian Center for Crafts - Tennessee Technological University
Smithville, TN
Louis Howard Katz on sun 26 may 96
Missed the first part of the thread. Oyster shells are great below 1500
deg. F. as temper. Above that temp they may cause lime blows. Some
sources say 1600 deg. . Recently a book suggested that the shells might
be helpfull making more alkaline clays workable.
When I was teaching in Columbia MO some grad Anthro/ Archaeology grads
were doing a project on why the local Native Americans switched from sand
temper to crushed sea shells. They first came by to find out why their
molds didn't release well frome the clay, they were greasing them up well.
We had a big discussion about soluble salts, lime blows, the effects of
aging time, methods of working. It was a lot of fun. If I stayed there I
would have hoped to teach a course on Ceramics techniques for
Archaeologists.
Louis
***************************************************
*Louis Katz lkatz@falcon.tamucc.edu *
*Texas A&M University Corpus Christi *
*6300 Ocean Drive, Art Department *
*Corpus Christi, Tx 78412 *
*Phone (512) 994-5987 *
**************************************************
christie lucero on sat 6 dec 03
I raise fancy chickens (banty frizzles, blue mottled cochins) for show. =
nobody ever eats them except the occasional coyote, I have the only =
chickens that die of old age. You can buy crushed oyster shell at pretty =
much any feed store.
By the by, has anyone tried or does anyone have an idea what is in =
Axner's new Dragon Skin glazes?
Christie Lucero
Snowlion Fine Arts
Coyote Creek, NM
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