Ray Aldridge on thu 10 feb 00
I was looking through CM from a couple years back, and came across an
article about Phil and Terri Mayhew. I used to run into him at shows
occasionally, back in the Dark Ages, and his work has continued in the same
vein-- faceted porcelain functional forms. But what I found most
interesting about the article was the fact that Phil now fires at Cone 16.
His reason was that glazes formed at that heat have qualities that cannot
be reproduced at lower temps-- and his glazes are much more beautiful, in
my opinion, than they were 20 years ago, when he was firing porcelain at a
more conventional heat.
So what's your feeling? Is this overkill? Many woodfire potters fire at
11 and 12, and when I was a young potter with a propane-fired kiln in the
woods, my firing temps gradually crept up until I was consistently firing
at 11-12, and my reason was the same as Phil's-- I could get glaze effects
at that temp that I found impossible to achieve at 10.
Another data point is the German potters whose work depends heavily on
magnificent glazes also seem to fire at very high temps.
So what's the deal here? Are those of us who fire at lower temps just
kidding ourselves that our glaze palette is as rich as that of potters
working at extreme temps? (Here let me make clear that I'm talking about
stoneware and porcelain, and not earthenware, which has a whole other range
of effects that can't be duplicated at high temps.)
Opinions?
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Stephen Grimmer on fri 11 feb 00
Ray,
When I finished grad school and built my kiln, I decided to fire at cone
9 to save on gas and wear and tear on the kiln. Gradually, the temperature I
fire to has been rising and now I like a hot 11. There seems to be a larger
interfacial zone between the glaze and porcelain at the higher temps, and
the glazes move a bit and flow together. I like that. On the other hand, I
have discovered that many of the most beautiful Longquan Celadons are fired
to cone 8 very slowly. Is there a more beautiful glaze anywhere?
On a personal note, I found the Mayhew glazes a bit gaudy for my tastes.
steve
--
Steve Grimmer
Bowling Green State University
Bowling Green, OH
----------
>From: Ray Aldridge
>To: CLAYART@LSV.UKY.EDU
>Subject: The Virtues of Heat
>Date: Thu, Feb 10, 2000, 1:52 PM
>
> ----------------------------Original message----------------------------
> I was looking through CM from a couple years back, and came across an
> article about Phil and Terri Mayhew. I used to run into him at shows
> occasionally, back in the Dark Ages, and his work has continued in the same
> vein-- faceted porcelain functional forms. But what I found most
> interesting about the article was the fact that Phil now fires at Cone 16.
>
> His reason was that glazes formed at that heat have qualities that cannot
> be reproduced at lower temps-- and his glazes are much more beautiful, in
> my opinion, than they were 20 years ago, when he was firing porcelain at a
> more conventional heat.
>
> So what's your feeling? Is this overkill? Many woodfire potters fire at
> 11 and 12, and when I was a young potter with a propane-fired kiln in the
> woods, my firing temps gradually crept up until I was consistently firing
> at 11-12, and my reason was the same as Phil's-- I could get glaze effects
> at that temp that I found impossible to achieve at 10.
>
> Another data point is the German potters whose work depends heavily on
> magnificent glazes also seem to fire at very high temps.
>
> So what's the deal here? Are those of us who fire at lower temps just
> kidding ourselves that our glaze palette is as rich as that of potters
> working at extreme temps? (Here let me make clear that I'm talking about
> stoneware and porcelain, and not earthenware, which has a whole other range
> of effects that can't be duplicated at high temps.)
>
> Opinions?
>
> Ray
>
>
> Aldridge Porcelain and Stoneware
> http://www.goodpots.com
Paul Lewing on fri 11 feb 00
Ray,
You may be right about glazes becoming much richer in texture at higher
temperatures, but I'm not so sure about color. Since most people do
high-fire reduction and mid-range oxidation, they assume that when they
fire higher, they lose colors. I think it's much more the switch in
atmosphere that destroys the colors. I've never known anybody who's
done oxidation above cone 10, but I do know that virtually all the
colors you can get at cone 6 oxidation you can also get at cone 10
oxidation.
Paul Lewing, Seattle
Rick Mahaffey on fri 11 feb 00
Ray,
I found just the opposite in Japan where most firings that I took part
in only went to 1250 Centigrade about Orton cone 7.5. IMHO I found
their glazes the most beautiful that I had ever seen. The glazes had a
depth and complexity that the glazes that I am used to in the US do not.
Perhaps for you a glaze that is very shiny is the ticket, but I found
the complex melts of glazes in use by some potters there simply amazing.
If isn't the heat, but what you do with it.
just my observation and my opinion.
Rick Mahaffey
Tacoma, Washington, USA
Ray Aldridge wrote:
>
> Another data point is the German potters whose work depends heavily on
> magnificent glazes also seem to fire at very high temps.
>
> So what's the deal here? Are those of us who fire at lower temps just
> kidding ourselves that our glaze palette is as rich as that of potters
> working at extreme temps? (Here let me make clear that I'm talking about
> stoneware and porcelain, and not earthenware, which has a whole other range
> of effects that can't be duplicated at high temps.)
>
Ray Aldridge on sat 12 feb 00
At 02:06 PM 2/11/00 EST, you wrote:
>----------------------------Original message----------------------------
>Ray,
> When I finished grad school and built my kiln, I decided to fire at cone
>9 to save on gas and wear and tear on the kiln. Gradually, the temperature I
>fire to has been rising and now I like a hot 11. There seems to be a larger
>interfacial zone between the glaze and porcelain at the higher temps, and
>the glazes move a bit and flow together. I like that. On the other hand, I
>have discovered that many of the most beautiful Longquan Celadons are fired
>to cone 8 very slowly. Is there a more beautiful glaze anywhere?
> On a personal note, I found the Mayhew glazes a bit gaudy for my tastes.
>
I know what you mean, Steve. But I see it as a matter of range-- I can
produce all the quiet glazes I want, so I've got *that* end of the glaze
bell curve covered. I'd like to be able to hit a few of the data points at
the other end of the curve, if I feel the need.
Another aspect of heat that I didn't mention in my first post is that
although most of the glazes I'm using at C8 contain boron, I find that
glazes fired high enough that boron isn't necessary for a fluid melt appeal
to me much more strongly. The surfaces are just more beautiful, to my
eye-- gloss boron glazes have an unpleasant glassy quality sometimes. I
diversify my fluxes with strontium, but I won't put up with the problems
associated with zinc, so to get really fluid melts at 8, I have to use
boron-- or so my experience has been.
It's funny you should mention celadons in that context, because I found
that the faux celadon-colored glaze I use at 8 looks better at 7. The
surface is less glossy, "fatter," if you know what I mean, but still
sufficiently transparent to effectively show oxide stained sgraffito on the
surface of the porcelain. I imagine that slightly-underfired effect would
be possible at any temp, with a properly formulated glaze.
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Ray Aldridge on sat 12 feb 00
At 02:06 PM 2/11/00 EST, you wrote:
>----------------------------Original message----------------------------
>Ray,
>You may be right about glazes becoming much richer in texture at higher
>temperatures, but I'm not so sure about color. Since most people do
>high-fire reduction and mid-range oxidation, they assume that when they
>fire higher, they lose colors. I think it's much more the switch in
>atmosphere that destroys the colors. I've never known anybody who's
>done oxidation above cone 10, but I do know that virtually all the
>colors you can get at cone 6 oxidation you can also get at cone 10
>oxidation.
Paul, I'm sure you're right about the influence of atmosphere on the normal
range of colors available from stains and many oxides-- certainly for
saturation and range of color, you'd want to go to oxidation earthenware.
But the glazes I'm thinking of are typified in a picture in Lanes _Studio
Ceramics_ of a bottle by Margarete Schott. It's a bottle fired in reduction
to 1360 C. It's about as gaudy as I could stand-- the colors range from
dark red through orange, yellow, green, and blue-green, and according to
the inscription are all derived from iron.
Karl Scheid and Ursula Schied also have examples in that book, fired to
1360 C. Some pictures are not in color but even in black and white the
quality of the glaze seems remarkable. The pots by the Wiegels (also fired
to 1360 C.) also show superior surface qualities, though they're more
conventional.
Anyway, I guess what I'm wondering is if there are glaze qualities
available to the potter at C 14 that are just not possible at C 10.
Looking at these German potters would cause one to think so.
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Dwiggins, Sandra (NCI) on sat 12 feb 00
So, Rick---
What do these potters have that we may be missing at ^6-7? Is it the clay
that's different, or are their chemicals somewhat different from ours? Are
these reduction and oxidation firings? I thought--after reading so many posts
about the electric kilns in Japan---that alot of firing is oxidation.
Sandy
-----Original Message-----
From: Rick Mahaffey [SMTP:rickmahaffey@home.com]
Sent: Friday, February 11, 2000 2:11 PM
To: CLAYART@LSV.UKY.EDU
Subject: Re: The Virtues of Heat
----------------------------Original message----------------------------
Ray,
I found just the opposite in Japan where most firings that I took part
in only went to 1250 Centigrade about Orton cone 7.5. IMHO I found
their glazes the most beautiful that I had ever seen. The glazes had a
depth and complexity that the glazes that I am used to in the US do not.
Perhaps for you a glaze that is very shiny is the ticket, but I found
the complex melts of glazes in use by some potters there simply amazing.
If isn't the heat, but what you do with it.
just my observation and my opinion.
Rick Mahaffey
Tacoma, Washington, USA
Ray Aldridge wrote:
>
> Another data point is the German potters whose work depends heavily on
> magnificent glazes also seem to fire at very high temps.
>
> So what's the deal here? Are those of us who fire at lower temps just
> kidding ourselves that our glaze palette is as rich as that of potters
> working at extreme temps? (Here let me make clear that I'm talking about
> stoneware and porcelain, and not earthenware, which has a whole other range
> of effects that can't be duplicated at high temps.)
>
iandol on sat 12 feb 00
------------------
To answer Ray=92s questions about higher firing for porcelain.
Perhaps the answer is obvious. It is not overkill. My opinion is that heat =
is
needed to make porcelain function in the fire and develop physical =
properties,
to become fully dense. Until porcelains achieve almost total density they =
cannot
work their optical magic. Sub micron sized bubbles scatter the light, cause
dulling. Prolonged heating helps to eliminate them. Vitreous phase will have
better optical properties as well, because longer times at higher =
temperatures
promote better mixing. Added light means visually enhanced glazes. In =
addition,
there will be an improved meld between glaze and body which may produce =
better
optical effects.
Ivor Lewis.Inquisitive life long pyromaniac
Hank Murrow on sun 13 feb 00
>----------------------------Original message----------------------------
>Ray,
> When I finished grad school and built my kiln, I decided to fire at cone
>9 to save on gas and wear and tear on the kiln. Gradually, the temperature I
>fire to has been rising and now I like a hot 11. There seems to be a larger
>interfacial zone between the glaze and porcelain at the higher temps, and
>the glazes move a bit and flow together. I like that. On the other hand, I
>have discovered that many of the most beautiful Longquan Celadons are fired
>to cone 8 very slowly. Is there a more beautiful glaze anywhere? steve
Dear Steve; Have a look at Kingery&Vandiver's, 'Ceramic Masterpieces' and
also Nigel Wood's new book, 'Chinese Glazes' for a detailed look at these
glazes and the rocks they came from. As I previously posted, it is possible
to locate, mine, process, and make pots from similar materials which will
turn out translucent, vitreous, and gorgeous @ C/8 in reduction. Jeff
Lawrence and Jon Pettyjohn are out looking as we speak. Me too, but first
I'm going to have some tea in one (helps inspire the digging) made by David
Stannard whose territory in Alaska is too cold for digging at present.
Hank in Eugene
ps: I'm up around C/11 too; except for these porcelainstones which must be
fired lower.....By the way, did you know that Shino turned into Oribe when
they started firing in the 'new and improved' noborigamas? The potters had
to decorate more, because the lovely soft surface and firecolor of Shino
was lost in the hotter and faster firing.
Rick Mahaffey on sun 13 feb 00
Sandy and Marj.,
If you are going to NCECA go to the Exhibition of work by Wasaburo
Takahashi at Arapahoe community College in Littleton. He fires from
1220 C to 1285 C. Wasa will be at NCECA and you can ask questions about
the character of the materials that he uses.
The materials are different. The clays are different. I ordered
Fukushima feldspar (a semi close approximation of Custer)
The grind was different. There were large chunks in it. The clays used
in glazes are different. The other materials are very different, except
for Kanada Choseki (Kanada = Canada, choseki = feldspar) Which I found
out was Nepheline Syenite.
Yes the glaze materials are mostly different. I think that the
materials are coarser and it is common practice to ball mill the glaze
after it is mixed.
The clays that I used were different also. The stoneware clay was less
sticky when compared to those we have on the West Coast. The stonewares
tended to be coarser that we use here in Washington State. My friend
Wasa Takahashi had a clay body that has a wonder sugary quality when
fired, It is a very white clay, I would love to find out how to make a
similar clay here in the US. (He told me that he got it for me to use
because it was the easiest clay in Japan to use.)
The porcelains were different, but I did not use much so I don't recall
the difference, other than the $78.00 bag that I bought (15 Kg.) was
cream colored and very difficult to throw, lots of cracking on just
thrown pieces. Tried handbulidng with better success.
"Dwiggins, Sandra (NCI)" wrote:
>
> ----------------------------Original message----------------------------
> So, Rick---
> What do these potters have that we may be missing at ^6-7? Is it the clay
> that's different, or are their chemicals somewhat different from ours? Are
> these reduction and oxidation firings? I thought--after reading so many post
> about the electric kilns in Japan---that alot of firing is oxidation.
>
> Sandy
>
>
Good evening Rick:
I was intriqued by your comments about glazes fired to 1250 and your
appreciation of them. Could you elaborate on their appeal.
What types of clay bodies were being used ? Marj.
John K Dellow on sun 13 feb 00
Perhaps its the time taken to fire . My understanding that in a
traditional Bizen firing the ambient temp may only get to 1200 C
( orton cone 5 )but after days of firing C 10 ( 1305 C )will have
dropped .
Rick Mahaffey wrote:
>
> ----------------------------Original message----------------------------
> Ray,
> I found just the opposite in Japan where most firings that I took part
> in only went to 1250 Centigrade about Orton cone 7.5. IMHO I found
> their glazes the most beautiful that I had ever seen. The glazes had a
> depth and complexity that the glazes that I am used to in the US do not.
> Perhaps for you a glaze that is very shiny is the ticket, but I found
> the complex melts of glazes in use by some potters there simply amazing.
>
> If isn't the heat, but what you do with it.
>
> just my observation and my opinion.
>
> Rick Mahaffey
> Tacoma, Washington, USA
>
> Ray Aldridge wrote:
>
> >
> > Another data point is the German potters whose work depends heavily on
> > magnificent glazes also seem to fire at very high temps.
> >
> > So what's the deal here? Are those of us who fire at lower temps just
> > kidding ourselves that our glaze palette is as rich as that of potters
> > working at extreme temps? (Here let me make clear that I'm talking about
> > stoneware and porcelain, and not earthenware, which has a whole other range
> > of effects that can't be duplicated at high temps.)
> >
--
John Dellow "the flower pot man"
Home Page http://www.welcome.to/jkdellow
http://digitalfire.com/education/people/dellow/
Stephen Mills on mon 14 feb 00
The kiln that I fire to cone 10 flat, 11 over, 12 starting, has not as
yet given me a pyrometer reading over 1220oC, a good demonstration of
accumulated heat-work!
The pyrometer is for me a useful stoking aid.
Steve
Bath
UK
In message , John K Dellow writes
>----------------------------Original message----------------------------
>Perhaps its the time taken to fire . My understanding that in a
>traditional Bizen firing the ambient temp may only get to 1200 C
>( orton cone 5 )but after days of firing C 10 ( 1305 C )will have
>dropped .
>
>Rick Mahaffey wrote:
>>
>> ----------------------------Original message----------------------------
>> Ray,
>> I found just the opposite in Japan where most firings that I took part
>> in only went to 1250 Centigrade about Orton cone 7.5. IMHO I found
>> their glazes the most beautiful that I had ever seen. The glazes had a
>> depth and complexity that the glazes that I am used to in the US do not.
>> Perhaps for you a glaze that is very shiny is the ticket, but I found
>> the complex melts of glazes in use by some potters there simply amazing.
>>
>> If isn't the heat, but what you do with it.
>>
>> just my observation and my opinion.
>>
>> Rick Mahaffey
>> Tacoma, Washington, USA
>>
>> Ray Aldridge wrote:
>>
>> >
>> > Another data point is the German potters whose work depends heavily on
>> > magnificent glazes also seem to fire at very high temps.
>> >
>> > So what's the deal here? Are those of us who fire at lower temps just
>> > kidding ourselves that our glaze palette is as rich as that of potters
>> > working at extreme temps? (Here let me make clear that I'm talking about
>> > stoneware and porcelain, and not earthenware, which has a whole other range
>> > of effects that can't be duplicated at high temps.)
>> >
>
>--
>
> John Dellow "the flower pot man"
>Home Page http://www.welcome.to/jkdellow
>http://digitalfire.com/education/people/dellow/
>
--
Steve Mills
Bath
UK
home e-mail: stevemills@mudslinger.demon.co.uk
work e-mail: stevemills@bathpotters.demon.co.uk
own website: http://www.mudslinger.demon.co.uk
BPS website: http://www.bathpotters.demon.co.uk
Tel: **44 (0)1225 311699
Fax: **44 (0)870 0526466
Dwiggins, Sandra (NCI) on mon 14 feb 00
Rick---Unfortunately, I won't be going to NCECA this year. But I would love to
see some of these glazes. I remember a book, from about 30 years ago, when I
first started making pots, about Australian potters. It was apparent that the
clay they were using was completely different from what I was working with. It
was coarser, had different minerals in it....and I WANTED SOME so badly, because
I was really into Bizen and rough textures then.
Maybe you can put some pics of these neat pots on a website somewhere.
Sandy
-----Original Message-----
From: Rick Mahaffey [SMTP:rickmahaffey@home.com]
Sent: Sunday, February 13, 2000 3:20 PM
To: CLAYART@LSV.UKY.EDU
Subject: Re: The Virtues of Heat
----------------------------Original message----------------------------
Sandy and Marj.,
If you are going to NCECA go to the Exhibition of work by Wasaburo
Takahashi at Arapahoe community College in Littleton. He fires from
1220 C to 1285 C. Wasa will be at NCECA and you can ask questions about
the character of the materials that he uses.
The materials are different. The clays are different. I ordered
Fukushima feldspar (a semi close approximation of Custer)
The grind was different. There were large chunks in it. The clays used
in glazes are different. The other materials are very different, except
for Kanada Choseki (Kanada = Canada, choseki = feldspar) Which I found
out was Nepheline Syenite.
Yes the glaze materials are mostly different. I think that the
materials are coarser and it is common practice to ball mill the glaze
after it is mixed.
The clays that I used were different also. The stoneware clay was less
sticky when compared to those we have on the West Coast. The stonewares
tended to be coarser that we use here in Washington State. My friend
Wasa Takahashi had a clay body that has a wonder sugary quality when
fired, It is a very white clay, I would love to find out how to make a
similar clay here in the US. (He told me that he got it for me to use
because it was the easiest clay in Japan to use.)
The porcelains were different, but I did not use much so I don't recall
the difference, other than the $78.00 bag that I bought (15 Kg.) was
cream colored and very difficult to throw, lots of cracking on just
thrown pieces. Tried handbulidng with better success.
"Dwiggins, Sandra (NCI)" wrote:
>
> ----------------------------Original message----------------------------
> So, Rick---
> What do these potters have that we may be missing at ^6-7? Is it the clay
> that's different, or are their chemicals somewhat different from ours? Are
> these reduction and oxidation firings? I thought--after reading so many post
> about the electric kilns in Japan---that alot of firing is oxidation.
>
> Sandy
>
>
Good evening Rick:
I was intriqued by your comments about glazes fired to 1250 and your
appreciation of them. Could you elaborate on their appeal.
What types of clay bodies were being used ? Marj.
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