Debbie Jestin on mon 31 dec 01
Hi, I'm curious as to why the majority of reduction people fire to cone 10
instead of cone 6?
Craig Martell on tue 1 jan 02
Hi:
It's not just reduction, some folks fire to cone 8-10 ox too. I used to do
hi fire oxidation but now I fire with gas and do reduction.
I'll just throw out one idea about my thinking on the subject.
Most of the fluxes that we use are high expansion materials. At cone 6 you
need to use more flux in glazes and some types of flux work against you
with regard to glaze fit. Potash and Soda feldspars are high expansion and
they are not as reactive at cone 6. You need to use more of the material
and also a mix of other fluxes to aid in fusion. My point is that you have
more choices of flux combinations at cone 8-10 because you have more heat
working on your behalf. There are fluxes that are lower expansion that are
very active at cone 6. Zinc oxide, Boron, and lithium. Magnesia is a good
low expander but it works a lot better at higher temps.
I'm not saying that I have a prejudice for cone 10 over 6. It's merely
what I prefer to do and what I'm concentrating on doing. You can make
glazes fit at cone 6 and you can make some very lovely work at that temp in
an electric or reduction kiln.
I have a friend who fires cone 6 reduction and does some excellent
work. His name is Pat Horsley and you can check him out on the web. He
has a link thru www.oregonpotters.org which is the website for the Oregon
Potter's Assoc. You can navigate to his website from the OPA homepage. He
has glaze and clay info on his site and pix of his cone 6R pots.
regards, Craig Martell in Oregon
chris clarke on tue 1 jan 02
I tried ^6 reduction at first when I got my gas kiln. Found that taking =
the same glazes up to ^10 just made them look better. So I changed to =
^10 after years in ^6 oxidation (and college years firing ^9 reduction). =
chris
temecula, california
chris@ccpots.com
www.ccpots.com
iandol on wed 2 jan 02
Dear Debbie Jestin,
You say <<fire to cone 10 instead of cone 6?...>>>
I wouldn't have a clue. But if true, it is an interesting proposition. =
One of the main reasons, and I take you know reduction glazes do not =
feature in some of the newer compendia of glaze recipes written =
especially for Cone six firers, may be that people have not been =
thinking along those lines.
If you can find a copy of Emmanuel Cooper's "Potters Book of Glaze =
Recipes", he has a section covering cone 5 to 8. His notes on many of =
these include comments about results from reduction firings. Janet De =
Boos in her glaze recipe books gives the results of firing in reduction =
for glazes maturing as low as cone 07. So the field has been explored in =
the last twenty five years.
Best regards,
Ivor Lewis. Redhill, South Australia.
Marcia Selsor on thu 3 jan 02
P>
> > fire to cone 10 instead of cone 6?
20 + years ago the ceramics program at MSUB was switched to a new building. With
it was the requirement to make the firing fit into 8 hours for the technical
assistant to fire the kilns without overtime. Of course the full time assistant
lasted 2 years. BUT we did reduce the temperature to be more conservation
oriented. The glazes looked like ^10. They were refined for many years and the
reliables have been submitted to mike baileys ^6 reduction glaze book.
The fuel savings between ^6 and ^10 is considerable. That is a key reason to
consider it.
I have my own gas kiln and continue to use ^6 in place of ^10 which I used for
the first 8 years in pottery. I feel that the making of pots is not really a
societal need as it was in the past. Therefore I feel that I shouldn't over
consume fuel for something that is peripheral. I am satisfied with the quality of
my glazes in ^6 reduction.
marcia Selsor in Montana
Paul Lewing on thu 3 jan 02
on 1/1/02 9:56 PM, iandol at iandol@TELL.NET.AU wrote:
> > fire to cone 10 instead of cone 6?
The majority of people who fire to cone 6 fire in oxidation because it's a
much bigger deal to build an electric kiln that will go to cone 10-
different element wire, more insulation.
Most people who fire in reduction fire to cone 10 or so because it generally
makes stronger pots. But the real reason is because back in the '50's and
'60's when the studio potter concept really took off, that's the temperature
all the hotshots fired to. Voulkos, Autio, Cushing, Rhodes, Ferguson,
Shaner, Wildenhain, Coper - all of what I once heard referred to as "The
Travelling Wilburys of Clay" - all fired to cone 10, and that's what all
their students learned.
Paul Lewing, Seattle
Martin Howard on fri 4 jan 02
Paul wrote:-
generally
makes stronger pots.>
Is there any proof of this?
'60's when the studio potter concept really took off, that's the temperature
all the hotshots fired to.>
That was when we did not seem to care about fuel costs or CO2 emissions.
Time for a change, friends?
Down to cones 1-3?
Martin Howard
Webbs Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
01371 850 423
martin@webbscottage.co.uk
http://www.webbscottage.co.uk
Updated 26/12/01
Jeff Lawrence on fri 4 jan 02
Debbie was wondering about cone 6 v cone 10
Hi Debbie,
Some reasons for cone 6:
- a few cone 10 firings can give unworthy shelves the bends pretty
bad. We're talking potato chips.
- it takes a couple of hours less than cone 10 (and if the shop is
40 minutes from home, as mine was, that matters!)
- costs a hair less, so you can stand a hair taller in your green-
ness ('how can you expend that fuel needlessly, you unholy profligates?')
Some reasons for cone 10 and up:
- you don't have to be as careful putting the glaze on -- drips and
blebs often become interesting instead of ugly (like the geek's looks
when you find they're a millionaire)
- there seems to be more available literature on cone 10, so you can
avoid grappling with technical issues altogether by following recipes
with blind devotion
- there are cone 10 fluxes (fluces?) that are refractory at cone 6,
so higher temperatures give you theoretically more glaze possibilities;
in other words, more random mixtures will melt to some degree.
- you can impress people with how high you fire ('need at least cone
12 for that stuff, man. Gotta soak it for four days.')
- the extra time and heat makes the resultant glazes look to many
more finished and the forms integrated holistically with their glaze;
e.g. my "Puddle-ware" sculpture series where the clay and glaze
harmonized completely into their namesake shapes on the kiln shelves.
Jeff Lawrence
jml@cybermesa.com
Michelle McCurdy on fri 4 jan 02
Hi,
Does it really make stronger pots at Cone 10 or does it depend on the
vitrification temp of the clay?? If you had clay that vitrified at ^6
wouldn't they be just as strong??
Michelle
Earl Brunner on fri 4 jan 02
Up to cone 11 and 12, and reduce the heck out of it.
Martin Howard wrote:
> Paul wrote:-
> > generally
> makes stronger pots.>
> Is there any proof of this?
>
> > '60's when the studio potter concept really took off, that's the temperature
> all the hotshots fired to.>
>
> That was when we did not seem to care about fuel costs or CO2 emissions.
> Time for a change, friends?
> Down to cones 1-3?
>
> Martin Howard
> Webbs Cottage Pottery
> Woolpits Road, Great Saling
> BRAINTREE, Essex CM7 5DZ
> 01371 850 423
> martin@webbscottage.co.uk
> http://www.webbscottage.co.uk
> Updated 26/12/01
>
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>
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>
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--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Terry Hunt on wed 5 jun 02
----- Original Message -----
From: "Craig Martell"
To:
Sent: Tuesday, January 01, 2002 1:27 PM
Subject: Re: Why not Cone 6 Reduction ?
> Hi:
>
> It's not just reduction, some folks fire to cone 8-10 ox too. I used to
do
> hi fire oxidation but now I fire with gas and do reduction.
>
> I'll just throw out one idea about my thinking on the subject.
>
> Most of the fluxes that we use are high expansion materials. At cone 6
you
> need to use more flux in glazes and some types of flux work against you
> with regard to glaze fit. Potash and Soda feldspars are high expansion
and
> they are not as reactive at cone 6. You need to use more of the material
> and also a mix of other fluxes to aid in fusion. My point is that you
have
> more choices of flux combinations at cone 8-10 because you have more heat
> working on your behalf. There are fluxes that are lower expansion that
are
> very active at cone 6. Zinc oxide, Boron, and lithium. Magnesia is a
good
> low expander but it works a lot better at higher temps.
>
> I'm not saying that I have a prejudice for cone 10 over 6. It's merely
> what I prefer to do and what I'm concentrating on doing. You can make
> glazes fit at cone 6 and you can make some very lovely work at that temp
in
> an electric or reduction kiln.
>
> I have a friend who fires cone 6 reduction and does some excellent
> work. His name is Pat Horsley and you can check him out on the web. He
> has a link thru www.oregonpotters.org which is the website for the Oregon
> Potter's Assoc. You can navigate to his website from the OPA homepage.
He
> has glaze and clay info on his site and pix of his cone 6R pots.
>
> regards, Craig Martell in Oregon
>
>
____________________________________________________________________________
__
> 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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