Cindy Strnad on wed 29 nov 00
I don't have any personal experience with raw glazing, but have read a bit
about it. One book, I think it was called "The Self-Sufficient Potter", or
some variant of that theme, recommended raw-glazing at the stiff
leather-hard stage.
Most of the talk I hear on the list seems to indicate glazing at the bone
dry stage. This fellow would glaze the outside, then wait a half a day or
day, and then glaze the inside. (Or vice-versa, depending on what was most
convenient.) It might be something to try, if cracking has been a problem.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
Alisa and Claus Clausen on wed 29 nov 00
Hi Steve,
Now my interest is perked again.
I have tried a few single firings and no such good results.=20
First all the greenware cracked up, then the pieces that
survived the glazing, either went slumpy or bust under
the firing. Admitedly, I had not done too much homework
on the process.
>From your vast experience with single firing, do you think
that I could example omit my bisque by painting on the same
glazes I normally use with the addition of CMC instead of
reformulating glazes with more clay?
What about firing ramps? Do they not need to be much slower
than normally up to around 500c?
I asked about some of this about a year ago when I first signed on
the list. I never got to far with it. But, for some of my work, I =
could
certainly use single firing, especially the bigger pots.
I would at all cutting back on my enormous electrical bill every =
quarter.
What range do you fire in? If it is 6, do you have any basic glaze
receipes I could use for a base? This would be very exciting test
trials for me, to do on green tiles!
Thanks in advance,
Best regards,
Alisa in Denmark
June Perry on wed 29 nov 00
Dear Alisa:
I haven't done much single firing but ha read a bit on it. Steve Hill
recommends that pots be a bit thicker for raw glazing . I found out why when
I raw glazed some thin mugs for a salt firing. There was that immediate "Oh
NO!" sound of clay vertically cracking starting at the rim; and even the
ones I thought made it through the glazing, cracked at the rim during the
firing. Only the bone dry raw glaze mugs cracked! Lesson learned -- in the
future, I will not raw glaze unless I leave a bit more thickness to the
walls, or glaze leather hard rather than bone dry.
Some glaze recipes I've seen call for glazing when pots are leather hard;
some glazes said that they work on bone dry pots; some mentioned glazing only
interior or exterior first and maybe spraying some water on the unglazed
portion. I suspect that's to equalize the tension and/or moisture.
One person mentioned that any glaze could be a once fire glaze with the
addition of about 3or was it5% bentonite ?
Normally, you might look for high clay bearing glazes for once firing. There
are always exceptions to the rule. I have found this out when rushing to get
a glaze test in a kiln and I used a raw tile instead of a bisqued one and the
glazes have, at times, come thru just fine.
You might check out the clayart archives on the web (the one where the
messages are listed by subject). I do believe this has been discussed before
on the list.
I think you just have to follow a few simple rules and through trial and
error find out what works for your glazes and body and firing schedule. I
would make sure those pots are totally dry before firing and to be doubly
safe, fire as slowly as your would for a bisque, in the early stages of the
firing.
Regards,
June
Lee Love on thu 30 nov 00
----- Original Message -----
From: Alisa and Claus Clausen
> Now my interest is perked again.
> I have tried a few single firings and no such good results.
> First all the greenware cracked up
Try glazing leather hard. I've never had anything crack when they are
glazed leather hard (slump, yes, but not crack.)
--
Lee Love
Mashiko JAPAN Ikiru@kami.com
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Steve Mills on thu 30 nov 00
Hi Alisa,
When I first tried single fire, I used two approaches; with glazes that
I couldn't alter by adding more clay I would add about two per cent
Bentonite to the recipe, this usually sorted out getting the glaze to
stick without crawling. With these low clay Glazes, I usually applied
them to bone dry wares, glazing the inside first, and then dipping
straight into the outside Glaze. If the pot was not going to be glazed
on the outside, I dipped it in plain water to balance the stresses. High
clay Glazes were applied to leather hard wares, allowing them to dry a
bit before applying a second glaze coat to the outside. From this you
may gather that at that time I was using a pretty tolerant clay. The
clay I am currently using wouldn't allow that sort of cavalier
behaviour!
Nowadays as all my work is salt glazed, I have one liner Glaze which is
applied to the inside before any turning or handling is done.
Single firing is much slower at the beginning, as you are combining a
biscuit programme with a Glaze programme.
With all my work I fire to cone nine (1285 degrees centigrade), though
nowadays the "number" is much higher, the effect is the same due to the
effect of wood-ash and salt!
There are some very good books on single fire, particularly one by
Dennis Parks.
Steve
Bath
UK
In message , Alisa and Claus Clausen writes
>Hi Steve,
>Now my interest is perked again.
>I have tried a few single firings and no such good results.=3D20
>First all the greenware cracked up, then the pieces that
>survived the glazing, either went slumpy or bust under
>the firing. Admitedly, I had not done too much homework
>on the process.
>
>=46rom your vast experience with single firing, do you think
>that I could example omit my bisque by painting on the same
>glazes I normally use with the addition of CMC instead of
>reformulating glazes with more clay?
>
>What about firing ramps? Do they not need to be much slower
>than normally up to around 500c?
>
>I asked about some of this about a year ago when I first signed on
>the list. I never got to far with it. But, for some of my work, I =3D
>could
>certainly use single firing, especially the bigger pots.
>I would at all cutting back on my enormous electrical bill every =3D
>quarter.
>
>What range do you fire in? If it is 6, do you have any basic glaze
>receipes I could use for a base? This would be very exciting test
>trials for me, to do on green tiles!
>
>Thanks in advance,
>Best regards,
>Alisa in Denmark
--
Steve Mills
Bath
UK
Steve Mills on fri 1 dec 00
That book was written by late Andrew Holden, now alas, well out of
print, that was the book that got me started. Not to be confused with a
set of four books written by a German author with the same title.
Steve
Bath
UK
In message , Cindy Strnad writes
>I don't have any personal experience with raw glazing, but have read a bi=
>t
>about it. One book, I think it was called "The Self-Sufficient Potter", o=
>r
>some variant of that theme, recommended raw-glazing at the stiff
>leather-hard stage.
>
>Most of the talk I hear on the list seems to indicate glazing at the bone
>dry stage. This fellow would glaze the outside, then wait a half a day or
>day, and then glaze the inside. (Or vice-versa, depending on what was mos=
>t
>convenient.) It might be something to try, if cracking has been a problem=
>=2E
>
>Cindy Strnad
>Earthen Vessels Pottery
>RR 1, Box 51
>Custer, SD 57730
>USA
>earthenv@gwtc.net
>http://www.earthenvesselssd.com
--
Steve Mills
Bath
UK
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