clennell on fri 27 jun 03
Sour Cherry Pottery
> My two kids are both geologists. One is a grad student, the other an
> undergrad. They were both previously art majors, the grad student having
> seriously contemplated ceramics as a major. They both gave up art because
> it wasn't quantitative enough.
>
> Anyway, they heard about someone making glaze from the local granite and
> were thrilled by the concept, so out came out the rock tumbler and we
> scooped up a hubcap full of "grus" or the crumbled stuff at the base of an
> outcrop. The stuff has been running along with a bunch of Mexican marbles
> for nearly a month now. There were two types of marbles, some chinese
> checker style solid color marbles and some regular catseye marbles. The
> chinese checker marbles are really reduced in size after a month (the
> diameter maybe as much as half of what they were). The catseye marbles
> don't seem to have changed much in size. My daughter the geology/ceramics
> student says this is good because we are adding silica to to the glaze.
I think you could have saved yourself a lot of tumbling had you calcined the
granite. I put the granite rocks in an old bisque bowl and put it in a
bisque firing. It then breaks up to a grog like material size with a few
taps of the hammer. The granite sprinkled on WET shino is a very lovely
temmoku type surface. Lately I have been wedging the granite into my clay
for a shigaraki look. The pinker the granite the more feldspar. The pink
granite has boiled out of the clay like a puss from a sore. Very
attractive! Hey, it's an acquired taste like single malts.
The darker granite have boiled out as a brown almost chocolate glaze.
In the viein of Davids Everything Matters approach I encourage everyone to
use a bit of this and that from your trips and walks. It makes your pots
yours. Hell, you can even share your formula and no one will be able to do
it.
here's my variation of the basic 221 ash glaze formula for 9-10
Pink granite 2
Ash 2
Ball clay 1
In the place of my pink granite try substituting your own local stone dusts
(the driveway) or feldspar with a pinch of iron as a coluourant.
Keep on rockin!
Tony
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King Street
Beamsville, Ontario
CANADA L0R 1B1
http://www.sourcherrypottery.com
clennell@vaxxine.com
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