search  current discussion  categories  techniques - misc 

clay additives/recycled clay

updated thu 5 feb 04

 

David Beumee on fri 30 jan 04


> These bloats happened to me several years ago when I was using
> Laguna B mix (c 10) redux.

The bloats are happening to me when I make recycled trimmings into usable
clay, but not when I use the original batch mixture from the manufacturer. The
only thing I know is to make up a batch, fire it and send a sample off to be
analysed. Maybe a bloat can be popped to see what's in it. Dave Finkelnburg
thinks it may be air pulled into the clay as it was mixed as a slurry, but the
recycled clay was run twice through a deairing pugmill. I don't know. This one
stumped even Pete Pinnell. There has to be some way to come up with an answer.

David Beumee
Earth Alchemy Pottery
Lafayette, CO
> These bloats happened to me several years ago when I was using
> Laguna B mix (c 10) redux. Never seemed to happen at c 10 in e kiln.
> This clay was straight from the box,,,wedged as I normally wedged.
> I whined to my supplier who had no explanation,,,I whined to Laguna,
> they didn't have an explanations either.
>
> I switched and am using Tucker's 1080 now ...never really did get an answer
> cept the typical blame the technique/potter stuff,,,
> If I sound ticked its because I got stuck with 20 boxes of it...
> bad batch ???
>
> Kathy Mc
> In manitoba where it's -41C this morning...
>
>
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Vince
> Pitelka
> Sent: Thursday, January 29, 2004 6:44 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: clay additives
>
>
> > Can you give any insight as to tiny bloats that appear in porcelain that
> has
> > been slaked down from trimmings using the wet method you describe?
>
> David -
> Hey, you're the clay whiz around here! But I can't see the logic behind Dr.
> Carty's opinion. How would inadequate blunging cause tiny bloats? But I
> suppose that is irrelevant, since you say blunged thoroughly.
>
> Has this happened in repeated firings? Is there any chance it is because of
> an anomaly in one firing? Porcelains are usually fired so close to the
> upper limit of their firing range. Any chance they were slightly overfired?
> Any warpage?
>
> Do you add throwing slop to this recycle, or is it just trimmings? The
> following is pretty far fetched, but I was trying to image a scenario where
> the throwing slop is primarily clay, while more feldspar is left behind on
> the surface of the wares. When the pieces are fired, this just becomes part
> of the interface and the glaze. But if you trim very far up the edges of
> pots, and then blunge those trimings, is it possible that it actually
> increases the flux content in the resulting recycle enough to cause this
> problem?
>
> Yea, yea, too far fetched.
>
> I wonder if there is any possible truth to what Dr. Carty says. Are you
> really soaking your trimmings - immersing them completely in water well
> above the level of the trimmings for a few days? I have always done it this
> way, decanting off all the excess water before mixing with the drill mixer.
> When I do it this way, I am able to get a very smooth slurry that is thick
> enough to mound up in rows to stiffen. That really isn't proper blunging,
> but I used to recycle a lot of porcelain this way, and I never experienced
> any micro bloating. That was many years ago, using Westwood (now Laguna)
> Kai and Sasuga porcelain bodies - thousands of pounds of trimmings recycled
> over the years.
>
> Doesn't seem like any of the above is going to help you much, and I wish I
> could offer more. Good luck, and let us know when you figure it out -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Office - wpitelka@tntech.edu
> 615/597-6801 x111, FAX 615/597-6803
> http://iweb.tntech.edu/wpitelka/
> http://www.tntech.edu/craftcenter/
>
> ____________________________________________________________________________
> __
> 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.
>
>
> ---
> Incoming mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.567 / Virus Database: 358 - Release Date: 1/24/2004
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.567 / Virus Database: 358 - Release Date: 1/24/2004
>
> ______________________________________________________________________________
> 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.

Fredrick Paget on fri 30 jan 04


> > These bloats happened to me several years ago when I was using........
...............
You mentioned doing Crystalline glazes and I wonder if you might have
contaminated the bricks in your kiln with something exotic .
Several years ago I fired some niobium in a crucible trying to make
oxide for crystal glazes and the stuff volatilized and contaminated
the bricks in the lower part of the kiln. Firings in that part of the
kiln had the kind of micro bloating you describe. It took several
firings to get rid of it.
Fred
--
From Fred Paget, Marin County, California, USA
fredrick@well.com

Ababi on sat 31 jan 04


In my experience the bloating happens when I mix two claybodies- might be both for
the same ^ I mix in the "slop" way so there are not any air bubble. I think it might be
the inter-relation between the unknown to us minerals in the mix that boil the mix and
lower its maturing point. Perhaps adding kaolin molochite or even grog up to 10%
would save the clay
Ababi Sharon
Glaze addict
Kibbutz Shoval Israel
ababisha@shoval.org.il
http://ababi.active.co.il
http://www.matrix2000.co.nz/Matrix%20Demo/Ababi.htm
Ceramics forum in Hebrew:

http://community.msn.co.il/comm_forum_topics.asp?ForumID=7894&PagePosition=1&ThreadPage=1&CommID=4804




---------- Original Message ----------

>> These bloats happened to me several years ago when I was using
>> Laguna B mix (c 10) redux.

> The bloats are happening to me when I make recycled trimmings into usable
>clay, but not when I use the original batch mixture from the manufacturer. The
>only thing I know is to make up a batch, fire it and send a sample off to be
>analysed. Maybe a bloat can be popped to see what's in it. Dave Finkelnburg
>thinks it may be air pulled into the clay as it was mixed as a slurry, but the
>recycled clay was run twice through a deairing pugmill. I don't know. This one
>stumped even Pete Pinnell. There has to be some way to come up with an
>answer.

> David Beumee
> Earth Alchemy Pottery
> Lafayette, CO
>> These bloats happened to me several years ago when I was using
>> Laguna B mix (c 10) redux. Never seemed to happen at c 10 in e kiln.
>> This clay was straight from the box,,,wedged as I normally wedged.
>> I whined to my supplier who had no explanation,,,I whined to Laguna,
>> they didn't have an explanations either.
>>
>> I switched and am using Tucker's 1080 now ...never really did get an answer
>> cept the typical blame the technique/potter stuff,,,
>> If I sound ticked its because I got stuck with 20 boxes of it...
>> bad batch ???
>>
>> Kathy Mc
>> In manitoba where it's -41C this morning...
>>
>>
>> -----Original Message-----
>> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Vince
>> Pitelka
>> Sent: Thursday, January 29, 2004 6:44 PM
>> To: CLAYART@LSV.CERAMICS.ORG
>> Subject: Re: clay additives
>>
>>
>> > Can you give any insight as to tiny bloats that appear in porcelain that
>> has
>> > been slaked down from trimmings using the wet method you describe?
>>
>> David -
>> Hey, you're the clay whiz around here! But I can't see the logic behind Dr.
>> Carty's opinion. How would inadequate blunging cause tiny bloats? But I
>> suppose that is irrelevant, since you say blunged thoroughly.
>>
>> Has this happened in repeated firings? Is there any chance it is because of
>> an anomaly in one firing? Porcelains are usually fired so close to the
>> upper limit of their firing range. Any chance they were slightly overfired?
>> Any warpage?
>>
>> Do you add throwing slop to this recycle, or is it just trimmings? The
>> following is pretty far fetched, but I was trying to image a scenario where
>> the throwing slop is primarily clay, while more feldspar is left behind on
>> the surface of the wares. When the pieces are fired, this just becomes part
>> of the interface and the glaze. But if you trim very far up the edges of
>> pots, and then blunge those trimings, is it possible that it actually
>> increases the flux content in the resulting recycle enough to cause this
>> problem?
>>
>> Yea, yea, too far fetched.
>>
>> I wonder if there is any possible truth to what Dr. Carty says. Are you
>> really soaking your trimmings - immersing them completely in water well
>> above the level of the trimmings for a few days? I have always done it this
>> way, decanting off all the excess water before mixing with the drill mixer.
>> When I do it this way, I am able to get a very smooth slurry that is thick
>> enough to mound up in rows to stiffen. That really isn't proper blunging,
>> but I used to recycle a lot of porcelain this way, and I never experienced
>> any micro bloating. That was many years ago, using Westwood (now Laguna)
>> Kai and Sasuga porcelain bodies - thousands of pounds of trimmings recycled
>> over the years.
>>
>> Doesn't seem like any of the above is going to help you much, and I wish I
>> could offer more. Good luck, and let us know when you figure it out -
>> - Vince
>>
>> Vince Pitelka
>> Appalachian Center for Craft
>> Tennessee Technological University
>> 1560 Craft Center Drive, Smithville TN 37166
>> Home - vpitelka@dtccom.net
>> 615/597-5376
>> Office - wpitelka@tntech.edu
>> 615/597-6801 x111, FAX 615/597-6803
>> http://iweb.tntech.edu/wpitelka/
>> http://www.tntech.edu/craftcenter/
>>
>>
>____________________________________________________________________________
>> __
>> 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.
>>
>>
>> ---
>> Incoming mail is certified Virus Free.
>> Checked by AVG anti-virus system (http://www.grisoft.com).
>> Version: 6.0.567 / Virus Database: 358 - Release Date: 1/24/2004
>>
>> ---
>> Outgoing mail is certified Virus Free.
>> Checked by AVG anti-virus system (http://www.grisoft.com).
>> Version: 6.0.567 / Virus Database: 358 - Release Date: 1/24/2004
>>
>>
>______________________________________________________________________________
>> 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.

>______________________________________________________________________________
>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.

Ivor and Olive Lewis on sat 31 jan 04


Dear David Beumee,
Bloats have a gas in them. So get the gas analysed. This will prompt
you to the nature of the chemical which is decomposing to create the
problem.
Best regards,
Ivor Lewis. Redhill, South Australia.

Connie Christensen on mon 2 feb 04


> The bloats are happening to me when I make recycled trimmings into
usable
> clay

I've been using clay that is part recycled and part new porcelain and have
had a few bloating problems - but only when I use shino. Is there a reason
why the claybody would bloat with shinos and not other glazes?

Connie
Denver
www.conniechristensen.com

Paul Herman on wed 4 feb 04


Hello Connie,

Does the offending shino have soda ash in it? If so, perhaps that could
be the cause, soda ash penetrating the body.

best wishes,

Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/

----------
>From: Connie Christensen
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: clay additives/recycled clay
>Date: Mon, Feb 2, 2004, 9:38 PM
>

>> The bloats are happening to me when I make recycled trimmings into
> usable
>> clay
>
> I've been using clay that is part recycled and part new porcelain and have
> had a few bloating problems - but only when I use shino. Is there a reason
> why the claybody would bloat with shinos and not other glazes?
>
> Connie
> Denver
> www.conniechristensen.com

Connie Christensen on wed 4 feb 04


Yes, the shino recipe has soda ash in it. Is there a way to prevent the
bloating from the soda ash if this is the problem? I also have another minor
problem with the shino in a specific part of the kiln but I want to get one
more firing in before describing it.

----- Original Message -----

> Hello Connie,
>
> Does the offending shino have soda ash in it? If so, perhaps that could
> be the cause, soda ash penetrating the body.
>
> best wishes,
>
> Paul Herman
> Great Basin Pottery
> Doyle, California US
> http://www.greatbasinpottery.com/
>
> ----------
> >From: Connie Christensen
> >To: CLAYART@LSV.CERAMICS.ORG
> >Subject: Re: clay additives/recycled clay
> >Date: Mon, Feb 2, 2004, 9:38 PM
> >
>
> >> The bloats are happening to me when I make recycled trimmings into
> > usable
> >> clay
> >
> > I've been using clay that is part recycled and part new porcelain and
have
> > had a few bloating problems - but only when I use shino. Is there a
reason
> > why the claybody would bloat with shinos and not other glazes?
> >
> > Connie
> > Denver
> > www.conniechristensen.com
>
>
____________________________________________________________________________
__
> 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.
>