Ann Testa on mon 14 jan 08
I just attended the Potter Council workshop in Berkeley
this weekend (it was fabulous) & Willie Hulce was one of
the presenters who said that she uses Cone 5 B-mix for
mugs & fires it to Cone 11 flat for the vitrification. We all
asked how that could that be possible? How could Cone 5
clay be fired to Cone 11 & not be a puddle on the shelf?
She assured us that she could do it. She even said at
one point she talked to a clay tech at Laguna who told
her she couldn't do it. She assumed he would know.
So I have to wonder if there isn't something else happening
with Margie's forms & that it's the clay that is not a good mix
with her forms.
Ann Testa
_www.clayartgallery.com_ (http://www.clayartgallery.com)
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
Marcia Selsor on tue 15 jan 08
On Jan 14, 2008, at 10:35 PM, Ann Testa wrote:
> I think Ann's comments that Willie Hulce uses ^5 B mix to ^11 makes
> a good point as well as Bill Shran advise for higher bisque and low
> glaze if you are using stilts..
I think the problem is not the clay, but the stilts. The clay is
shrinking during the glaze and the stilts are not. This stresses the
clay.
Marcia Selsor
http://marciaselsor.com
William & Susan Schran User on tue 15 jan 08
On 1/14/08 11:35 PM, "Ann Testa" wrote:
> I just attended the Potter Council workshop in Berkeley
> this weekend (it was fabulous) & Willie Hulce was one of
> the presenters who said that she uses Cone 5 B-mix for
> mugs & fires it to Cone 11 flat for the vitrification. We all
> asked how that could that be possible? How could Cone 5
> clay be fired to Cone 11 & not be a puddle on the shelf?
> She assured us that she could do it. She even said at
> one point she talked to a clay tech at Laguna who told
> her she couldn't do it.
Well, unless Laguna would provide the exact mix of their ^5 & ^10 B Mix,
it's probably impossible to know. I would suppose they're both based on the
same mix, but the ^5 having proportionally a higher percentage of melting
agents.
Many clays can be fired higher than the cone suggested by the manufacturer,
but the type of form that will be fired plays a part in success or failure.
A cylindrical form, made on the wheel with a flat bottom supported by the
shelf would have a better chance to survive being fired at a hotter
temperature than a flat slab supported at a few points fired to a lower
temperature, but still at the pyroplastic state.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Dolita Dohrman on tue 15 jan 08
^5 B-mix is vitrified at ^5-^6. I don't know why someone would feel
they need to fire it to ^11 for vitrification. I can see getting
away with firing a clay to a couple of cones higher than indicated,
but much more and the clay becomes almost brittle.
Dolita
On Jan 14, 2008, at 11:35 PM, Ann Testa wrote:
> I just attended the Potter Council workshop in Berkeley
> this weekend (it was fabulous) & Willie Hulce was one of
> the presenters who said that she uses Cone 5 B-mix for
> mugs & fires it to Cone 11 flat for the vitrification. We all
> asked how that could that be possible? How could Cone 5
> clay be fired to Cone 11 & not be a puddle on the shelf?
> She assured us that she could do it. She even said at
> one point she talked to a clay tech at Laguna who told
> her she couldn't do it. She assumed he would know.
> So I have to wonder if there isn't something else happening
> with Margie's forms & that it's the clay that is not a good mix
> with her forms.
>
> Ann Testa
> _www.clayartgallery.com_ (http://www.clayartgallery.com)
>
>
>
> **************Start the year off right. Easy ways to stay in shape.
> http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
>
> ______________________________________________________________________
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> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, or change
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Josh Berkus on tue 15 jan 08
Ann,
> On 1/14/08 11:35 PM, "Ann Testa" wrote:
> > I just attended the Potter Council workshop in Berkeley
> > this weekend (it was fabulous) & Willie Hulce was one of
> > the presenters who said that she uses Cone 5 B-mix for
> > mugs & fires it to Cone 11 flat for the vitrification. We all
> > asked how that could that be possible? How could Cone 5
> > clay be fired to Cone 11 & not be a puddle on the shelf?
> > She assured us that she could do it. She even said at
> > one point she talked to a clay tech at Laguna who told
> > her she couldn't do it.
This is kind of surprising to me. Southern Oregon Pottery Supply, who run an
electric-fire studio in Talent Oregon, advised me to switch from Cone 5 B Mix
to Cone 10 B Mix for Cone 6 firing because they were getting bowls slumping
at Cone *6* with the Cone 5 mix.
So, I'm thinking that Willie got an unusual batch or something.
--
Josh "the Fuzzy" Berkus
San Francisco
dbarnese on tue 15 jan 08
This is interesting. I use Cone 5 B-mix and several months ago, had a
load that got overfired in the bottom half of the kiln. I would guess
it went to between cone 8-9. The clay started to bubble, the pieces
were ruined, in my opinion. I use one of the mugs but I would not
consider any of the pieces from that firing to be sellable. I think
they would have melted if they had gone much longer.
--Dina Barnese
Zizziba Studio
Flagstaff, Arizona
http://www.zizziba.com
http://ZizzibaStudio.etsy.com
--- In clayart@yahoogroups.com, Ann Testa wrote:
>
> I just attended the Potter Council workshop in Berkeley
> this weekend (it was fabulous) & Willie Hulce was one of
> the presenters who said that she uses Cone 5 B-mix for
> mugs & fires it to Cone 11 flat for the vitrification. ...
gayle bair on tue 15 jan 08
I'm not so sure Marcia...
there are certain shapes that will slump for sure with B-Mix.
For instance, a bowl with a horizontal rim is sure to slump
whereas an angled rim fires perfectly.
Gayle Bair
Tucson AZ
Bainbridge Island WA
gayle@claybair.com
www.claybair.com
On Jan 15, 2008, at 5:58 AM, Marcia Selsor wrote:
> On Jan 14, 2008, at 10:35 PM, Ann Testa wrote:
>
>> I think Ann's comments that Willie Hulce uses ^5 B mix to ^11 makes
>> a good point as well as Bill Shran advise for higher bisque and low
>> glaze if you are using stilts..
> I think the problem is not the clay, but the stilts. The clay is
> shrinking during the glaze and the stilts are not. This stresses the
> clay.
>
>
> Marcia Selsor
> http://marciaselsor.com
>
> ______________________________________________________________________________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, or change
> your
> subscription settings here: http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.com
Dan Semler on thu 17 jan 08
Hi Ron, Ann,
I had a quick check on the Laguna website and Cone 5 Bmix WC-401 is
quoted as having 2.3% +/-1% absorption at about cone 5. So perhaps its
not as tight as we are assuming at cone 5, and thus 11 is not
impossible. It would be interesting to see what absorption is at cone
11 I guess.
Here's the link
Thx
D
Ron Roy on thu 17 jan 08
Something wrong here - if a clay is properly vitrified at cone 6 (water
proof) and you fire it to cone 11 it's going to be a mess. Certainly
bloated and sticking to shelves at the very least.
Some body is pulling your leg I think.
Maybe it was cone 10 B Mix.
RR
>I just attended the Potter Council workshop in Berkeley
>this weekend (it was fabulous) & Willie Hulce was one of
>the presenters who said that she uses Cone 5 B-mix for
>mugs & fires it to Cone 11 flat for the vitrification. We all
>asked how that could that be possible? How could Cone 5
>clay be fired to Cone 11 & not be a puddle on the shelf?
>She assured us that she could do it. She even said at
>one point she talked to a clay tech at Laguna who told
>her she couldn't do it. She assumed he would know.
>So I have to wonder if there isn't something else happening
>with Margie's forms & that it's the clay that is not a good mix
>with her forms.
>
>Ann Testa
>_www.clayartgallery.com_ (http://www.clayartgallery.com)
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Ron Roy on sat 19 jan 08
Hi Dan,
If it's 2.3 at 5 then probaly less than 2 at 6 - the trouble with melting
clays at lower themps is - you have to add sinificatly more melter to get
the job done. It's just not possible to have a clay not be overfired over a
range like that - if it's water proof at 5 or 6.
RR
>Hi Ron, Ann,
>
>I had a quick check on the Laguna website and Cone 5 Bmix WC-401 is
>quoted as having 2.3% +/-1% absorption at about cone 5. So perhaps its
>not as tight as we are assuming at cone 5, and thus 11 is not
>impossible. It would be interesting to see what absorption is at cone
>11 I guess.
>
>Here's the link
>
>Thx
>D
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Paul Herman on sat 19 jan 08
Hello All,
A few times we have had people slip in some cone 5 B mix at our wood
firings. When fired to cone 10 or 11, it makes a nice puddle of white
matt glass, and has gotten on the posts and other pots. It comes off
with a big hammer and chisel, and sometimes has taken a chunk of
silicon carbide shelf with it. Obviously I tend to discourage the use
of this clay in our kiln, or at cone 10 or above.
Anytime someone joins us in wood firing, I always lecture them about
the clay, but some gets through sometime. Not the last few firings,
thankfully.
best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
http://greatbasinpottery.com
On Jan 17, 2008, at 4:56 PM, Dan Semler wrote:
> Hi Ron, Ann,
>
> I had a quick check on the Laguna website and Cone 5 Bmix WC-401 is
> quoted as having 2.3% +/-1% absorption at about cone 5. So perhaps its
> not as tight as we are assuming at cone 5, and thus 11 is not
> impossible. It would be interesting to see what absorption is at cone
> 11 I guess.
>
> Here's the link
>
> Thx
> D
>
Lee on sun 20 jan 08
On Jan 18, 2008 9:56 AM, Dan Semler wrote:
> Hi Ron, Ann,
>
> I had a quick check on the Laguna website and Cone 5 Bmix WC-401 is
> quoted as having 2.3% +/-1% absorption at about cone 5. So perhaps its
> not as tight as we are assuming at cone 5, and thus 11 is not
> impossible. It would be interesting to see what absorption is at cone
> 11 I guess.
Certainly, we can easily be fooled if we only look at the
numbers. The glaze you use on the body (glaze fluxes clay) along
with the thickness of the clay are factors.
A friend of mine uses Continental Mid-ranged clay in his Anagama
firing up to cone 13. It colors nicely and catches ash. But, he
makes the work thicker for the anagama and does not glaze it.
--
Lee in Mashiko, Tochigi Japan
http://mashikopots.blogspot.com/
"Tea is nought but this: first you heat the water, then you make the
tea. Then you drink it properly. That is all you need to know."
--Sen No Rikyu
"Let the beauty we love be what we do." - Rumi
Ron Roy on mon 21 jan 08
Sometimes the numbers are just what you need - in this case - if the clay
is labeled good from cone 6 to cone 10 - and it works at cone 13 you can be
sure it will be very open at cone 6.
It is simply impossible to have a clay be waterproof at cone six and not be
melted at cone 13.
RR
>On Jan 18, 2008 9:56 AM, Dan Semler wrote:
>> Hi Ron, Ann,
>>
>> I had a quick check on the Laguna website and Cone 5 Bmix WC-401 is
>> quoted as having 2.3% +/-1% absorption at about cone 5. So perhaps its
>> not as tight as we are assuming at cone 5, and thus 11 is not
>> impossible. It would be interesting to see what absorption is at cone
>> 11 I guess.
>
> Certainly, we can easily be fooled if we only look at the
>numbers. The glaze you use on the body (glaze fluxes clay) along
>with the thickness of the clay are factors.
>
> A friend of mine uses Continental Mid-ranged clay in his Anagama
>firing up to cone 13. It colors nicely and catches ash. But, he
>makes the work thicker for the anagama and does not glaze it.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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