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naked raku (clay, that is) problem

updated sat 31 aug 96

 

Neupet@aol.com on fri 12 jul 96

We tried to make a clay slip to use as a resist in raku. It needs to craze
during raku firing and peel off after cooling. For my first attempt,
beginner's luck, I gathered up some slurry from the recycle bucket (Standard
Ceramics 119 and 245), added a few handfuls of 48 mesh grog, painted it on a
white clay which had been bisqued (Miller 55 or cone 6 porcelain, I'm not
sure). I used some tape on the pot first (a la Jane Perryman), then painted
on numerous layers of the gunk. When it was dry I applied a clear crackle
raku glaze, fired it to 1860x, then into the sawdust. Ten minutes later, out
came an easy to remove outside and a beautiful white pot with black lines
from the tape and other smoke markings from where the slurry had crazed. I
can't do it again. Every slurry application since has cracked nearly off the
pot as it dried.

Here's what I have tried:
1) repeating the first successful experience (no measures)
2) equal amounts of fireclay and EPK with 10% and 20% 48 mesh grog
3) David Roberts resist slip recipe from Perryman:
China Clay 3 parts, Flint 2 parts, by volume (according to
the Hessenberg book)

ALL TOTAL FAILURES!!!!!!

I hope one of you can help. I've been at a workshop this past week on Long
Beach Island, NJ at The Loveladies Foundation taught by Ted Camp from
Bradenton, FL. It's been wonderful and I return on Monday for the last week
with, I hope, your collective wisdom in printouts in my bag.

Thank you.

Lynne Berman

Marie-Claire Stil on mon 5 aug 96

Hi Lynne,

I'm catching up with Clayart after being away, I don't seem to see an
answer to your post on juli 12th.

I have also been experimenting whenever the opportunity arises, with
these result:
- with David Robert's resist slip as you mentioned and a glaze from
90% borax frit and 10% kaolin, the slip gets off beautifully, the
natural black crackled network is real nice, the lines near the neck
and at the bottom of a turned round pot are thicker (I love it) than
tthe ones on the belly;
- with the same slip and a glaze made of 65% Fritte 3110 and 35%
Gerstley Borate, the slip doesn't get off easily, so adieu pot;
- with a resist slip from 2 parts kaolin, 3 parts kwartz (more kwartz
would let the slip go mor easily) and the glaze above (Fritte 3110 and
G.B.), I got a beautiful result: lovely big black networks on a silky,
smooth white all over a turned cylinder narrowing towards the top.

The pots are made from a French white porcelain clay and well
burnished. Slip and glaze got through mesh 80.

You could try what you like best and adjust?

Good luck!

Greetings!

Marie-Claire
Vlaardingen in The Netherlands
Western Europe