mitzi on mon 27 oct 03
I recently fired a kiln load of glazed pots. Some were made from
Standard 112 and some from Standard 266. I fired to cone 6 but it slightly
overfired as the witness cone 7 was a little bent. The #112 was fine but
the #266 was very distorted and bloated. It melted down onto the stilts
enough that the stilt can't be removed. The glaze was sort of orange
peeled.
I called the supplier and he recommended doing a longer bisque to
prevent the bloating and said that he had had several people call about that
particular clay.
Next glaze fire I only fired to cone 4 to prevent the melting, but the
#266 clay still slumped down over the stilts. #112 was ok, but not the
nice warm tan I get at cone 6 and the glazes were not quite matured.
I suppose I can use the dark brown for sculpture unglazed and fired to a
lower temp, but what will give me a nice dark brown and not slump? Has
anyone else had a problem with this clay and what did you do to correct it.
-- Mitzi
With my last firing done for the year. Moved back from my lake place where
the wheel and kiln are.
Chris Schafale on tue 28 oct 03
Mitzi,
Generally, mid-range and high-fire clays are not meant
to be fired on stilts. The 266 is well known for bloating
at cone 6, but it might be fine at cone 4 or 5 if you don't
use stilts.
Chris
On 27 Oct 2003 at 6:15, mitzi wrote:
I recently fired a kiln load of glazed pots. Some
were made from
Standard 112 and some from Standard 266. I fired to
cone 6 but it slightly
overfired as the witness cone 7 was a little bent. The
#112 was fine but
the #266 was very distorted and bloated. It melted
down onto the stilts
enough that the stilt can't be removed. The glaze was
sort of orange
peeled.
I called the supplier and he recommended doing a
longer bisque to
prevent the bloating and said that he had had several
people call about that
particular clay.
Next glaze fire I only fired to cone 4 to prevent the
melting, but the
#266 clay still slumped down over the stilts. #112 was
ok, but not the
nice warm tan I get at cone 6 and the glazes were not
quite matured.
I suppose I can use the dark brown for sculpture
unglazed and fired to a
lower temp, but what will give me a nice dark brown
and not slump? Has
anyone else had a problem with this clay and what did
you do to correct it.
-- Mitzi
With my last firing done for the year. Moved back from
my lake place where
the wheel and kiln are.
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Brian Haviland on tue 28 oct 03
At 06:15 AM 10/27/03 -0500, you wrote:
> I recently fired a kiln load of glazed pots. Some were made from
>Standard 112 and some from Standard 266. I fired to cone 6 but it slightly
>overfired as the witness cone 7 was a little bent. The #112 was fine but
>the #266 was very distorted and bloated. It melted down onto the stilts
>enough that the stilt can't be removed. The glaze was sort of orange
>peeled.
> SNIP
Hi Mitzi
I use the same clays but mostly #112 .When i used the #266 I only
had very fine pinholes where the glaze had pooled.
I found that if i fired my bisq. loads and put a hold on them for 30 min.
it really helped with that problem. I figured it was getting rid of more
gas and impurities during the longer fire. Have you used other glazes with
the 266 or just one. It could be a glaze/clay problem. I had problems with
using ocean green on the 266 it would pinhole every time no matter what i
fired bisq. to. Hope this sheds a little light on your problem..Good luck...
Brian Haviland
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
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Cheryl Litman on tue 28 oct 03
I found that the 266 could be fired to a cone 5 without any bloating problems or a fast cone 6 but the slower the firing or any cone over 6 and about a third of the ware bloated. The clay is rated cone 4-6 but even a long cone 6 firing is generally too much for it.
I never had slumping or melting. Just the bloating. Stopped firing above 5 and it was fine. I haven't used that clay for about 5 years but at the time I had boxes from numerous batches.
Cheryl Litman
-- mitzi wrote:
I recently fired a kiln load of glazed pots. Some were made from
Standard 112 and some from Standard 266. I fired to cone 6 but it slightly
overfired as the witness cone 7 was a little bent. The #112 was fine but
the #266 was very distorted and bloated. It melted down onto the stilts
enough that the stilt can't be removed. The glaze was sort of orange
peeled.
I called the supplier and he recommended doing a longer bisque to
prevent the bloating and said that he had had several people call about that
particular clay.
Next glaze fire I only fired to cone 4 to prevent the melting, but the
#266 clay still slumped down over the stilts. #112 was ok, but not the
nice warm tan I get at cone 6 and the glazes were not quite matured.
I suppose I can use the dark brown for sculpture unglazed and fired to a
lower temp, but what will give me a nice dark brown and not slump? Has
anyone else had a problem with this clay and what did you do to correct it.
-- Mitzi
With my last firing done for the year. Moved back from my lake place where
the wheel and kiln are.
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
dalecochoy on wed 29 oct 03
S266 is a beautiful clay, but I had so many time consuming larger pots
ruined with it's bloating ( cone 51/2-6) that I finally quit using it and in
fact threw out what I had remaining. Standard was very nice about it and
gave me some replacement clay. Suggested no firing above cone 5 ( even
though it says 6). I found it was ok for smaller THIN pots but , just quit
buying it.
I'd love it if they could solve the bloating problem.
Dale Cochoy
----- Original Message -----
From: "Chris Schafale"
To:
Sent: Tuesday, October 28, 2003 6:26 AM
Subject: Re: dark brown clay problem
> Mitzi,
> Generally, mid-range and high-fire clays are not meant
> to be fired on stilts. The 266 is well known for bloating
> at cone 6, but it might be fine at cone 4 or 5 if you don't
> use stilts.
> Chris
> On 27 Oct 2003 at 6:15, mitzi wrote:
> I recently fired a kiln load of glazed pots. Some
> were made from
> Standard 112 and some from Standard 266. I fired to
> cone 6 but it slightly
> overfired as the witness cone 7 was a little bent. The
> #112 was fine but
> the #266 was very distorted and bloated. It melted
> down onto the stilts
> enough that the stilt can't be removed. The glaze was
> sort of orange
> peeled.
> I called the supplier and he recommended doing a
> longer bisque to
> prevent the bloating and said that he had had several
> people call about that
> particular clay.
> Next glaze fire I only fired to cone 4 to prevent the
> melting, but the
> #266 clay still slumped down over the stilts. #112 was
> ok, but not the
> nice warm tan I get at cone 6 and the glazes were not
> quite matured.
> I suppose I can use the dark brown for sculpture
> unglazed and fired to a
> lower temp, but what will give me a nice dark brown
> and not slump? Has
> anyone else had a problem with this clay and what did
> you do to correct it.
> -- Mitzi
Ron Roy on fri 31 oct 03
Hi Dale - thanks for this - it is a clue.
OK for thin pots suggests this is a bisque firing problem - carbon takes
longer to burn out of thicker clay so I am pretty sure it is the reduced
iron in the clay that is leading to over firing.
RR
>S266 is a beautiful clay, but I had so many time consuming larger pots
>ruined with it's bloating ( cone 51/2-6) that I finally quit using it and in
>fact threw out what I had remaining. Standard was very nice about it and
>gave me some replacement clay. Suggested no firing above cone 5 ( even
>though it says 6). I found it was ok for smaller THIN pots but , just quit
>buying it.
>I'd love it if they could solve the bloating problem.
>Dale Cochoy
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
dalecochoy on fri 31 oct 03
Hi Ron,
I hate to disagree with you but that wasn't it, in fact, that was the first
thing that was brought to my attention. Standard ditto's the comment on all
the impurities to gain the color but the slow bisqueing wasn't the
clue.Since so much of my stuff is kinda large slab built stuff I bisque fire
slower than anyone on earth! I normally take 24 hours to bisque and almost
never have a problem now with anything. and, since I started reading your
posts /recommendations I now bisque to 04 instead of 05.
I'd have to say it's the clay ( not the bisqueing) , unless fairly small and
thin.
BTW, I heard that S266 was originated by a Pittsburg area bonsai potter
several years back, Don Gould, who was well known and sought after for
bonsai pots but now is more into fused glass art. Anyone know for sure? I've
not had his phone number for a few years.
Regards,
Dale Cochoy
----- Original Message -----
From: "Ron Roy"
Subject: Re: dark brown clay problem
> Hi Dale - thanks for this - it is a clue.
>
> OK for thin pots suggests this is a bisque firing problem - carbon takes
> longer to burn out of thicker clay so I am pretty sure it is the reduced
> iron in the clay that is leading to over firing.
> RR
> >S266 is a beautiful clay, but I had so many time consuming larger pots
> >ruined with it's bloating ( cone 51/2-6) that I finally quit using it and
in
> >fact threw out what I had remaining. Standard was very nice about it and
> >gave me some replacement clay. Suggested no firing above cone 5 ( even
> >though it says 6). I found it was ok for smaller THIN pots but , just
quit
> >buying it.
> >I'd love it if they could solve the bloating problem.
> >Dale Cochoy
>
> Ron Roy
Ron Roy on sun 2 nov 03
Hi Dale,
I'm still not sure - if it is how come the thin pieces are OK?
How is the oxygen relpaced in your kiln and how slow from red heat up to 04?
Any spys open? Vent running?
RR
>Hi Ron,
>I hate to disagree with you but that wasn't it, in fact, that was the first
>thing that was brought to my attention. Standard ditto's the comment on all
>the impurities to gain the color but the slow bisqueing wasn't the
>clue.Since so much of my stuff is kinda large slab built stuff I bisque fire
>slower than anyone on earth! I normally take 24 hours to bisque and almost
>never have a problem now with anything. and, since I started reading your
>posts /recommendations I now bisque to 04 instead of 05.
>I'd have to say it's the clay ( not the bisqueing) , unless fairly small and
>thin.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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