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wedging/production // re: s- cracks off the hump

updated mon 12 oct 98

 

Bill Amsterlaw on sun 11 oct 98

Hi Clayart:

<< I watched someone at a craft show this weekend making little jars and
she started with a square of clay cut right from the bag. No wedging, no
rounding. >>

I would not be able to do this with the clay body I use - nor would I want
to.

If I don't wedge my clay, I get a lot of s-cracks. A pug mill puts "fault
lines" in the clay which will promote s-cracks. You can deal with this by
orienting the clay at 90 degrees from the pug axis, but wedging is a better
way because it does other good things for the clay.

If the clay has been sitting in the bag for some time since it was pugged,
it is likely that it is no longer homogeneous. The best time to pug clay
is just before you intend to use it.

Clay gets stiff just sitting around (thixotropy?). When you slam it and
mash it, the clay wakes up ... becomes more responsive. The best time to
wedge is just before you throw.

The easiest way to wedge is to use a fixed wire at the wedging table. It
is a pain to try to describe the technique. (A video or demo is worth a
thousand words.) I learned the technique by studying a commercial video on
Jerry Brown ("Unbroken Tradition"). Jerry Brown is a 9th generation folk
potter from Alabama. He uses raw clay which he digs by hand. His clay
mixer is powered by a mule. In the video, he wedges a 27-lb mass of clay in
about 60 seconds. Once you master this technique, it is a pleasurable
activity which quickly tells you a lot about the condition of your clay
while mixing and de-airing it as well as any de-airing pugmill can do it.

- Bill Amsterlaw (wamster@slic.com)
Plattsburgh, NY