Richard Mahaffey on sat 5 mar 05
Mel said------------------------
so often the system of shape, clay, glaze, how fired make
the deal happen.
I say ----------------------
"Always!" The thing I learned in Japan was that many of the potters
consider the whole system there. I have a friend that will change
clays, glazes and kilns while altering the firing temperature by 10 *C
to get the pots he wants. consider the "Whole Magilla" as a package.
I have started to use this approach by using different clays to get the
glaze effects that I want that are apart from color changes. Still
working on it when I get the chance (Teaching now comes with an
avalanche of paper _ good because our snow pack is quite low these
days.).
Here most potters seem to be locked into a kiln and a specific cone.
It is easier to alter the firing temp that to alter the glaze to fit a
temperature.
By the way, Mel, I think that saggars might be a reason that some
Celadons that are right at the edge of going green stay blue. The pots
tend to be much harder to re-oxidize if they are in a tight saggar.
The wadding is green so it lets the reduction in while it is in the
bisque faze until the wadding gets vitreous (if it ever does). No
yellow layer on the outside of the Celadon no green from the light
going through the yellow to blue to clay bouncing back through blue and
then the thin yellow layer producing green reflected light which hits
your eye. The green tends to be more prevalent in Celadons with iron
content closer to .5 % and above.
By the way, I saw tons and tons of saggars in China near the Kiln that
is still producing porcelain in the traditional method just outside
Jing de Zhen (pronounced Jing doh Juhn).
Best,
Rick Mahaffey
Tacoma, WA
Edwards on sun 6 mar 05
Rick, Mel,
Thanks for the posts. It confirms some of the things that I've noticed.
If I may add a bit along the same line. When I was at the Celadon
Research Institute in Gan- jin they have a section on 12th century kiln
furniture. Lots of saggers, the saggers was not much bigger on the
inside than the bowls that were put into them. To my surprise were kiln
posts that were used. The posts were a mushroom shaped affair, about 12"
high, they were used to raise pots up of the floor of the kiln, so in
effect you could have two layers of pots. Pots were set on quartz chips.
The people at the institute were very helpful-- I think that they were a
little surprised that someone would be interested in old saggers!
In Mokpo and Gwangju they have some great celadon pots from the Wandu
boat treasure. The Wando boat was in route to Japan from China, when it
sunk in the 12 or 13 hundreds. Thousands of pots were recovered in
pistine condition. The pots were out of the kiln and packaged -- to be
finished (spurs ground off etc) at their destination. Many of the
rice/tea bowls were still stacked 10 high one inside the other,
separated by quartz chips. Very dense pack.
I think that you are right about saggers helping celadons and the "Whole
Magilla" idea. Perhaps we could take it a step further and include the
location of the kiln. The kilns at Gan Jin are at sea level, next to a
bay, dug into the ground. I would think that would help keep the glazes
from re-oxidizing! Furutani Michio talks somewhat about location of
kilns and the effects on reduction/ oxidation.
Rick--thanks for some of your insight on coloration of celadons. I have
been working on particle size distribution also to explain why some of
the old celadons do what they do. I think that a consistant fine
particle size might produce some good celadons, but I think that some
great celadons can be had with some coarser particles in the mix. This
gets down to what you like. Lots to think about.
Cheers
~Craig
Richard Mahaffey wrote:
> Mel said------------------------
>
> so often the system of shape, clay, glaze, how fired make
> the deal happen.
>
> I say ----------------------
>
> "Always!" The thing I learned in Japan was that many of the potters
> consider the whole system there. I have a friend that will change
> clays, glazes and kilns while altering the firing temperature by 10 *C
> to get the pots he wants. consider the "Whole Magilla" as a package.
> I have started to use this approach by using different clays to get the
> glaze effects that I want that are apart from color changes. Still
> working on it when I get the chance (Teaching now comes with an
> avalanche of paper _ good because our snow pack is quite low these
> days.).
>
> By the way, Mel, I think that saggars might be a reason that some
> Celadons that are right at the edge of going green stay blue. The pots
> tend to be much harder to re-oxidize if they are in a tight saggar.
> The wadding is green so it lets the reduction in while it is in the
> bisque faze until the wadding gets vitreous (if it ever does). No
> yellow layer on the outside of the Celadon no green from the light
> going through the yellow to blue to clay bouncing back through blue and
> then the thin yellow layer producing green reflected light which hits
> your eye. The green tends to be more prevalent in Celadons with iron
> content closer to .5 % and above.
>
> By the way, I saw tons and tons of saggars in China near the Kiln that
> is still producing porcelain in the traditional method just outside
> Jing de Zhen (pronounced Jing doh Juhn).
>
>
Richard Mahaffey on sun 6 mar 05
Craig,
I think the uniform particle size of our materials are great for making
toilets (and for faster firing in an industrial setting, the almighty
$, you know(Ok, well not so almighty these days)), but a varied
particle size in the glaze materials will give a more complex melt and
much more complex appearance.
It does require a longer, slower firing to get the larger size
particles to melt, but that too is part of the whole package.
All things being equal except location of kilns might account for the
ease with which some people achieve certain results that are a struggle
for others.
I have seen those post with their four sided shape wider at the foot
and top, narrower where the rim of the four bowls below are. Saw one
with a blue and white pot on it that was found just off the coast of
Shikoku. The potter that had it said that it was made in Otani - home
of huge 300 gallon 600 pound stoneware jars made on kick wheels (see
Potters of Japan - Peeler's video). Said that they made blue and white
there before the stoneware that they make now.
I also saw the contents of a ship wreck with pots in Fukuoka at the
history museum there. Some remaining ship boards are in the display.
The pots are stacked as they were found in the hull with a see though
ship holding them so you can see how they were packed.
On the celadon color (blue and saggars) I was discussing it with Dr.
Ken Stevens (PhD chemistry, MFA clay) at an NCECA and a famous cone 4
to 6 oxidation firing author said that it was an impossibility and that
the Chinese did not fire in saggars. His entourage thought he was so
wonderful.
I think he had better stick to electric kilns. Even then I
wonder............................
I have not been to Korea yet, but I expect to get there in '08 when our
conference is hosted there. I will have a chance to go to China in
'06 and will keep my eyes open and my hearing aids turned up!
Thanks,
Rick
On Sunday, March 6, 2005, at 06:52 AM, Edwards wrote:
> Rick, Mel,
> Thanks for the posts. It confirms some of the things that I've
> noticed. If I may add a bit along the same line. When I was at the
> Celadon Research Institute in Gan- jin they have a section on 12th
> century kiln furniture. Lots of saggers, the saggers was not much
> bigger on the inside than the bowls that were put into them. To my
> surprise were kiln posts that were used. The posts were a mushroom
> shaped affair, about 12" high, they were used to raise pots up of the
> floor of the kiln, so in effect you could have two layers of pots.
> Pots were set on quartz chips. The people at the institute were very
> helpful-- I think that they were a little surprised that someone would
> be interested in old saggers!
> In Mokpo and Gwangju they have some great celadon pots from the Wandu
> boat treasure. The Wando boat was in route to Japan from China, when
> it sunk in the 12 or 13 hundreds. Thousands of pots were recovered in
> pistine condition. The pots were out of the kiln and packaged -- to be
> finished (spurs ground off etc) at their destination. Many of the
> rice/tea bowls were still stacked 10 high one inside the other,
> separated by quartz chips. Very dense pack.
>
> I think that you are right about saggers helping celadons and the
> "Whole Magilla" idea. Perhaps we could take it a step further and
> include the location of the kiln. The kilns at Gan Jin are at sea
> level, next to a bay, dug into the ground. I would think that would
> help keep the glazes from re-oxidizing! Furutani Michio talks somewhat
> about location of kilns and the effects on reduction/ oxidation.
> Rick--thanks for some of your insight on coloration of celadons. I
> have been working on particle size distribution also to explain why
> some of the old celadons do what they do. I think that a consistant
> fine particle size might produce some good celadons, but I think that
> some great celadons can be had with some coarser particles in the mix.
> This gets down to what you like. Lots to think about.
> Cheers
> ~Craig
>
> Richard Mahaffey wrote:
>
>> Mel said------------------------
>>
>> so often the system of shape, clay, glaze, how fired make
>> the deal happen.
>>
>> I say ----------------------
>>
>> "Always!" The thing I learned in Japan was that many of the potters
>> consider the whole system there. I have a friend that will change
>> clays, glazes and kilns while altering the firing temperature by 10 *C
>> to get the pots he wants. consider the "Whole Magilla" as a package.
>> I have started to use this approach by using different clays to get
>> the
>> glaze effects that I want that are apart from color changes. Still
>> working on it when I get the chance (Teaching now comes with an
>> avalanche of paper _ good because our snow pack is quite low these
>> days.).
>>
>> By the way, Mel, I think that saggars might be a reason that some
>> Celadons that are right at the edge of going green stay blue. The
>> pots
>> tend to be much harder to re-oxidize if they are in a tight saggar.
>> The wadding is green so it lets the reduction in while it is in the
>> bisque faze until the wadding gets vitreous (if it ever does). No
>> yellow layer on the outside of the Celadon no green from the light
>> going through the yellow to blue to clay bouncing back through blue
>> and
>> then the thin yellow layer producing green reflected light which hits
>> your eye. The green tends to be more prevalent in Celadons with iron
>> content closer to .5 % and above.
>>
>> By the way, I saw tons and tons of saggars in China near the Kiln that
>> is still producing porcelain in the traditional method just outside
>> Jing de Zhen (pronounced Jing doh Juhn).
>>
>>
>
Edwards on sun 6 mar 05
Richard Mahaffey wrote:
> Craig,
> I think the uniform particle size of our materials are great for making
> toilets , but a varied
> particle size in the glaze materials will give a more complex melt and
> much more complex appearance.
> It does require a longer, slower firing to get the larger size
> particles to melt, but that too is part of the whole package.
Well, I think that we know what you think about particle size The nub
of the matter is that in the US there are few options to get anything
other than uniform highly refined ,white bread, bland, monocultured,
corporate pablum for glaze materials. Lately for woodfiring I've been
gathering my own materials and crushing them myself. I'll have some
celadon samples in the spring woodfire. It's a little over the top-- but
what the hell, if I'm gonna stand in front of the firebox for five
days..... I'd better have a good reason to.
>
> I have seen those post with their four sided shape wider at the foot
> and top, narrower where the rim of the four bowls below are. Saw one
> with a blue and white pot on it that was found just off the coast of
> Shikoku.
> I also saw the contents of a ship wreck with pots in Fukuoka at the
> history museum there. Some remaining ship boards are in the display.
> The pots are stacked as they were found in the hull with a see though
> ship holding them so you can see how they were packed.
Sounds like we went to different schools together.
>
> I have not been to Korea yet, but I expect to get there in '08 when our
> conference is hosted there. I will have a chance to go to China in
> '06 and will keep my eyes open and my hearing aids turned up!
Just got my tickets for Korea last week. Leaving June 1, the day after
school is out. Unfortunately no Japan this summer, to many things to do
in Korea, I'll really miss not seeing Lee and Jean this time. Maybe in
the fall.
Cheers,
Craig
>
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