Mary Hays on sat 28 sep 96
I have a few raku questions if anyone can answer i'd appreciate it.
can earthenware be raku'd, are there problems with cracking?
If you use terra cotta clay, buff, or stoneware, would the same glaze look
different on each one because of the clay bodies?
Thanks for your help.
Jim Connell or set clayart mail on sun 29 sep 96
WINTHROP UNIVERSITY Electronic Mail Message
Date: 28-Sep-1996 10:44am EDT
From: James Connell
CONNELLJ
Dept: Art and Design
Tel No: 323-2126
TO: SMTP%"CLAYART@lsv.uky.edu" ( _SMTP%"CLAYART@lsv.uky.edu" )
Subject: RE: Raku questions
Any clay can (in theory) be used in rakuing providing it has the necessary
amount of aggregate material in it to open the body (to preventing it from
cracking too much due to the thermal shock). Years ago I remember not believing
a porcelain body could be rakued. It made it through and although I think its a
waste of some expensive clay it proved to me anything goes. Obviously clay that
would mature way below the raku temps might have a problem, but you never know.
I have taken pots that where originally fired in cone 10 stoneware and then
rakued them and even they made it through the process. Experiment, you'll never
know until you try it.
Different colored clays will affect the end results of the glaze just as the
same glaze on a porcelain piece can look different on a stoneware piece. To
get a white raku crackle start with a white body and put on a white crackle
glaze (actually a white crakle raku glaze is nothing more than a clear glaze
like Soldner's old standby 80 Colemanite, 20 Neph. Sy). On a white clay body it
will be white. On a terra-cotta body it will be orange to brown. Even darker
copper saturate raku glazes like Copper Penny or Black Magic will change
apperance going from light to dark clay bodies. They are less noticeable but
nevertheless different.
So, the key word is experiment and have fun!
Jim
chull@startext.net on sun 29 sep 96
Mary,
I use a white stoneware claybody for raku and even then there is
occasional cracking but less than with low fire clay. Also, I don't
immerce the piece in water after smoking as it increases the rate of
cracking and isn't necessary. Any clay will smoke to black where it is
not glazed. As far as how certain glazes look on different clays, that
would depent on the opacity of the glaze and any concern with a chemical
reaction of the claybody and the glaze altering it's appearence would
probably just have to be tested with each combination. I have not
noticed any changes with the ones I have used.
Cynthia
TX
Mary Hays wrote:
>
> ----------------------------Original message----------------------------
> I have a few raku questions if anyone can answer i'd appreciate it.
> can earthenware be raku'd, are there problems with cracking?
> If you use terra cotta clay, buff, or stoneware, would the same glaze look
> different on each one because of the clay bodies?
> Thanks for your help.
Dannon Rhudy on sun 29 sep 96
>----------------------------Original message----------------------------
>I have a few raku questions
>can earthenware be raku'd, are there problems with cracking?
>If you use terra cotta clay, buff, or stoneware, would the same glaze look
>different on each one because of the clay bodies?
>Thanks for your help.
>
I have raku'd many clay bodies, including terracotta, porcelain, stoneware,
what-
ever. I've not had problems, even with large pieces, thrown or handbuilt.
I have found that some glazes differ sliightly with darker claybodies,
especially
the whites, which are sometimes beige. But those are things which must be
tested in each instance to know what will happen. My experience can only
be a very general guide; you need your own experience to know.
Throw or build some small forms and just try them; it won't take long, and
it will
tell you far more than pages of someone else's how-I-did-it.
Dannon Rhudy
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