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domed lids - throwing on plaster bats

updated wed 18 sep 02

 

vince pitelka on tue 17 sep 02


> While I throw domed lids the way Vince describes, as very shallow bowls,
and
> I also have thrown them off a hump which give me no trouble if I don't
> exceed about nine inch diameter, there WAS AN ARTICLE in CM sometime
> -some years? --ago showing how someone made a curved bat and threw
> domed lids on that bat. Might be an idea .....

Lili -
I used that technique in production in California, and it worked very well.
I took molds off kids balls and case lots of hemispherical bats, and for
larger lids I cast a slew of bats from several sizes of woks. That gave me
a good selection of different sizes and curvatures. I would center a domed
plaster bat on a clay pancake (no need to really stick it down for this
operation), and then center a small lump of clay at top center on the bat,
and then spread the lump across the surface of the bat, trimming the outer
edge to the desired diameter.

As soon as I trimmed the diameter I would score, slurry, and add another
small lump in the center and throw a knob. When I tried to throw the knob
from the center of the original lump I got S-cracks under the knob, from
lack of compression. It takes no more time to add a little lump afterwards
to throw the knob, and I never had S-cracks when I did it that way.

And surprisingly, after throwing these lids, I could place the plaster bats
on a rack high above my gas heater, and in less than an hour I could remove
the lids from the bats and throw another set.

I think these lids were a little sterile - all the lids from one bat had
exactly the same curvature, and there was little opportunity for variation.
But it was possible to add relief decoration with a roulette or bisque stamp
to the top surface, and it was possible to throw the lid with a thicker rim
at the outer edge. That helped.
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://www.craftcenter.tntech.edu/