Jeff Lawrence on sun 2 may 99
Bill wrote:
>> looking for good lowfire talcbody.
>> have never used lowfire whites.
>> any help is appreciated.
>> thanks,
>> bill
Hi Bill,
A 50:50 clay:talc body, the vaunted "hobby body" is amazing for low-fire
slipcasting. This basic recipe is used by ceramics shops everywhere,
usually without much need for technical awareness, because it is so
remarkably forgiving. You can unmold pieces in the early morning, pop them
in the gas kiln (electric firing causes explosions because I think of
inadequate ventilation) and fire them to temperature -- cone 06 to 04 -- in
6-8 hours. This clay is short, but using only very plastic clays might make
a throwing/jiggering body. Unless you are a throwing god, the clay might
not be quite as forgiving, because the pieces would be thicker.
An advantage of this body is flexibility. I changed the basic recipe to
correct glaze fit problems -- more clay cures shivering, less clay cures
crazing. I use 60% clay (a mix of ball clays and kaolins), 40% talc (texas
talc with about 9% calcium carbonate). This clay softens at ^6 in a
relatively fast (7-8 hour) oxidation firing, and looks to be even softer in
reduction (not tested, just observed). Other alterations I've heard of but
not tried are:
- add silica to cure shivering
- add feldspar or nepheline syenite to lower the vitrification point
- add colorants to taste
WARNING: it is hard to take yourself seriously when your clay is a hobby
body...you may find yourself drawn inexplicably to make Elvis statues and
sad-eyed ceramic clowns...
Have fun,
Jeff
Jeff Lawrence
jml@sundagger.com
Sun Dagger Design
Rt. 1 Box 394L
Espanola, NM 87532
vox/fax 505-753-5913
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