Michael McDowell on tue 13 mar 07
Arthur Lee writes:
"I just saw a color photograph of a platter by Shoji Hamada with a Persimmon
/ Kaki glaze - it totally blew my socks off! It's an amazing glaze. Turns
out that it's common in Mashiko, Japan, where - according to Hamada - it's
made from a local stone (called Mashiko Stone) and wood ash. Period..."
Arthur,
It would help if you could post a link to a photo of this Kaki glaze that
you like so much. Do you have any idea if this effect is produced in Mashiko
at the cone and atmosphere that you are looking to duplicate it at? I doubt
that using the same materials would be of much help to you in this quest if
you are not going to reproduce the firing conditions as well. Better to show
us somehow the finished glaze effect that you are after and the firing
conditions that you want to produce this effect from. The Kaki/persimmon
effect is produced by an iron saturate glaze, but so is Temmoku. My
experience of these glazes is that they can be produced in a wide variety of
firing conditions, but each firing regimen needs its own recipe/formula.
You also write:
"There is one version which was analyzed for the MC6G book and looked like a
prime candidate for both crazing and
shivering!!"
I'm wondering what you could be talking about here. Of course any glaze
could be considered a candidate for either crazing or shivering if a clay
body of inappropriatly greater or lesser thermal expansion is used with it.
In general though the glaze base for an iron saturate glaze will need to be
especially low expansion because the addition of significant iron oxide will
radically increase thermal expansion.
So perhaps you could ask your question again in a way that would give us all
more to go on...
Michael McDowell
Whatcom County, WA, USA
michael@mcdowellpottery.com
http://www.McDowellPottery.com
Arthur Lee on tue 13 mar 07
I just saw a color photograph of a platter by Shoji Hamada with a Persimmon
/ Kaki glaze - it totally blew my socks off! It's an amazing glaze. Turns
out that it's common in Mashiko, Japan, where - according to Hamada - it's
made from a local stone (called Mashiko Stone) and wood ash. Period.
I've looked through the archives for a cone 6 look-alike of Persimmon /
Kaki, but without much success. There is one version which was analyzed for
the MC6G book and looked like a prime candidate for both crazing and
shivering!! Apart from that, I couldn't find much.
So, can anyone help me with a glaze that duplicates Hamada's Persimmon? I
really don't want to have to try importing bags of Mashiko Stone from Japan!
Many thanks,
Arthur Lee
Englewood, Florida
arlee3@ewol.com
Hank Murrow on thu 15 mar 07
On Mar 14, 2007, at 9:41 PM, arlee34224 wrote:
> The plate itself (size not
> given) looks to be white porcelain or a very light stoneware with the
> design painted with a resist. The glaze is a deep red-orange of
> varying degrees of darkness, suggesting that it was painted on rather
> than dipped. The edges (rim and the edges of the design) are edged in
> black and there are black flecks of varying size in the design areas.
> The black bits look to be a natural development of the glaze and not
> painted on. Part of the power of the piece is that the glaze gives a
> smooth, but interesting, background to a powerful design. There were
> no notes with the photo to indicate firing temperature or conditions.
Dear Arthur;
More likely the glaze was poured/dipped over the clear under glaze with
resist on the underglaze. The variations in color come mainly from two
things. First, the complexity of the parent rock (this is true for most
minimally processed rocks), and second, the variability of thickness of
application. The glaze is black near the edges of the khaki because the
iron is dissolved in the clear glaze and turns the khaki into a tenmoku
on a local basis. The power of many place-based pots is such
variability exploited in a careful way by the potters who mined and
loved their materials. The industrial revolution has pretty much
destroyed that integrity except for the very persistent potters who
mine and process their own local rocks.
The greatest pots of the Song Dynasty, were made only from Petuntse(a
weathered volcanic rock) and covered with the gorgeous celadon
glaze(which was limestone 20% and petuntse 80%). So the greatest pots
from Jingdezhen were made from just two local materials six centuries
ago, before cones, Brent wheels, and gas kilns. reminds me of a
favorite contemporary harpsichord builder who declared he was "making
progress....... right back to the seventeenth century".
Just a thought.......
Cheers, Hank
www.murrow.biz/hank
arlee34224 on thu 15 mar 07
--- In clayart@yahoogroups.com, Michael McDowell wrote:
>
> Arthur,
>
> It would help if you could post a link to a photo of this Kaki
glaze that
> you like so much. Do you have any idea if this effect is produced
in Mashiko
> at the cone and atmosphere that you are looking to duplicate it at?
I doubt
> that using the same materials would be of much help to you in this
quest if
> you are not going to reproduce the firing conditions as well.
Better to show
> us somehow the finished glaze effect that you are after and the
firing
> conditions that you want to produce this effect from. The
Kaki/persimmon
> effect is produced by an iron saturate glaze, but so is Temmoku. My
> experience of these glazes is that they can be produced in a wide
variety of
> firing conditions, but each firing regimen needs its own
recipe/formula.
>
Michael,
Your points are well taken. I'd like to be able to show you the
photo, but it's printed in a book (International Arts and Crafts;
Flame Tree Publishing; 2005; p. 369) and I don't see any way to do it
without breaking a couple of copyrights. The plate itself (size not
given) looks to be white porcelain or a very light stoneware with the
design painted with a resist. The glaze is a deep red-orange of
varying degrees of darkness, suggesting that it was painted on rather
than dipped. The edges (rim and the edges of the design) are edged in
black and there are black flecks of varying size in the design areas.
The black bits look to be a natural development of the glaze and not
painted on. Part of the power of the piece is that the glaze gives a
smooth, but interesting, background to a powerful design. There were
no notes with the photo to indicate firing temperature or conditions.
I am told that the Mashiko Stone glaze is oxidation fired and has a
pretty wide firing range. I would want to use it - or a substitute -
at cone 6 oxidation. I have also been told that fluxing Mashiko stone
with wood ash will produce a Temmoku.
> You also write:
> "There is one version which was analyzed for the MC6G book and
looked like a
> prime candidate for both crazing and
> shivering!!"
>
> I'm wondering what you could be talking about here. Of course any
glaze
> could be considered a candidate for either crazing or shivering if
a clay
> body of inappropriatly greater or lesser thermal expansion is used
with it.
> In general though the glaze base for an iron saturate glaze will
need to be
> especially low expansion because the addition of significant iron
oxide will
> radically increase thermal expansion.
>
The analysis of a persimmon glaze that might both shiver and craze,
is found for Gibby's Wild Rose/Kaki at:
http://www.frogpondpottery.com/glazestability/glaze0008.html
I was startled to see that one glaze might have a tendency to both
shiver and craze, but then I am still quite new at this.
> So perhaps you could ask your question again in a way that would
give us all
> more to go on...
>
I'll see if I can find a link to a omparable piece that I can post
without violating copyright.
Many thanks for your help and interest.
Arthur
> Michael McDowell
> Whatcom County, WA, USA
> michael@...
> http://www.McDowellPottery.com
>
>
______________________________________________________________________
________
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Michael McDowell on sat 17 mar 07
Arthur,
While I still don't have reference to a particular outcome for the Kaki
effect you are seeking to duplicate, I believe I do have a sense of what you
are after from your textual description. I believe Hank Murrow is, as usual,
right on with his suggestion of how the glaze would be applied for the
effect you are after. And John Britt has offered formulas for kaki glazes at
cone 10. It remains to get this reworked into a formula that will suit your
firing. I have the impression that you want to achieve this effect at cone 6
in an electric kiln. I have every expectation that you should be able to do
that. I am a little surprised that there hasn't been a good cone 6 recipe
offered here on the list. I would attribute that to the fact that your first
post wasn't all that clear about just what you want to do, and to the fact
that many members are distracted with NCECA right now.
So you are going to have to do some work on this yourself. There are a few
hints that you can take from what has been offered that should help guide
your experimentation.
1. Start with an iron bearing clay or stone. Here's where you can bring in
local or otherwise significant materials to personalize your efforts. The
Kaki effect that I am currently using
(http://www.mcdowellpottery.com/urn%2323.htm) has about 40% Mount Saint
Helens Ash. It matures at cone 10/11 in reduction, so the formula will be of
little use to you. Alberta Slip, Albany Slip, Red Art clay are all possible
starting points.
2. You will need to add iron. This is an iron saturate effect, the final
recipe will have somewhere between 6% and 10% iron, and not all of that will
come from your iron bearing clay or stone.
3. Be sure to get some Phosphorous included (P2O5). This often comes from
bone ash or tri-calcium phosphate. Although it may be a component of the
local stone. Phosphorous is referred to in the literature as an "alternate
glass former". It would seem that the bright iron red color is only micron
thick layer over a black substrate, Phosphorous seems to promote formation
of this colorful "skin".
4. Choose your fluxes to minimize thermal expansion. All fluxes have
suggested minimum and/or maximum "limits" suggested for a given cone range.
I am not speaking with any authority when it comes to cone 6, these are just
hints from what I've found working with the effect at higher cones.
Magnesium does not seem to inhibit this effect so that would be a good one
to maximize. Lithium is also quite compatible with the effect you seek, and
good for reducing thermal expansion. Just be sure to get your lithium from
spodumene, not lithium carbonate. That was the problem with the formula you
mentioned earlier. Lithium carbonate is soluble so the flux will migrate
through the piece as the water is evaporating from application. You will get
high concentrations of lithium flux at the edges of the piece where water
vapor leaves, leaving the dissolved flux behind. This can lead to shivering
at the edges due to the low thermal expansion. On the other hand soluble
lithium flux will be scarce say in the glaze pooled in the bottom of a bowl,
and that area may develop crazing. Lithium in Spodumene is not a soluble, so
it is a safe ingredient to a point. Ron Roy has cautioned me in the past to
limit my use of Lithium, whatever the source, to 1/4 the total amount of
K/NaO flux used in the glaze. Of course rules are made to be broken...
The reason you will want to keep thermal expansion as low as possible is
that all that iron oxide is going to be very expansive. Knowing that will be
part of this glaze makes it imperative to keep expansion down in other
areas.
Well, that's all I can think of that will help you on this quest. Good
Luck...
Michael McDowell
Whatcom County, WA, USA
michael@mcdowellpottery.com
http://www.McDowellPottery.com
Lee Love on sun 18 mar 07
On 3/18/07, Michael McDowell wrote:
> that. I am a little surprised that there hasn't been a good cone 6 recipe
> offered here on the list. I would attribute that to the fact that your first
> post wasn't all that clear about just what you want to do, and to the fact
> that many members are distracted with NCECA right now.
It may be problematic trying to duplicate this glaze at cone
6 temps because of the high amount of iron (more than tenmoku) and the
fact that fluxing the glaze turns it into tenmoku, while keeping it
stable for functional us. But too, if you are willing to fire to
cone 8 or 9, it works fine in electric.
Our closest counterpart to Mashiko Kaki is Albany slip.
One way to go may be to use the Reeve Synthetic Kaki and do a Currie
grid, adjusting flux and iron.
Below is the transparent glaze I used under Reeve Mashiko when I
worked in St. Paul (I found my old post in Google)*
Lee Love on mon 6 may 02
----- Original Message -----
From: "Lesley Alexander"
> You mention they always put a limestone glaze under Kaki...
> interesting. Could you give an example of a limestone glaze? What does
> this do? Thanks, Lesley
Hi Lesley. The standard glaze at the workshop is nami jiro, basically
half ballclay and half wood ash, with kaolin added (5 to 20%,
depending on the
area of the kiln.) For use under the kaki, a different glaze
is used: choseki
nami jiro. It is a different formula, including feldspar. You get the
best kaki color with this glaze under it.
Back home, I used something I got from Shirley Johnson: L G Clear
(light green clear.) Here is the recipe. I believe it is a
variation of the
Leach cone 8 1234, adjusted for cone 9/10:
Custer 27
OM4 14
Whiting 20.5
Flint 31.5
Kaolin 7
Lee in Mashiko
.___________________________________________________
| Lee Love ^/(o\| Practice before theory.
| Ikiru@kami.com |\o)/v - Sotetsu Yanagi - |
`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~'
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://potters.blogspot.com/
"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau
"Let the beauty we love be what we do." - Rumi
arlee34224 on mon 19 mar 07
Thank you very much, all of you who replied to my original questions
about Hamada's Persimmon / Kaki glaze. You have given me some great
starting points for testing.
Lee Love's posting here anticipates what would have been my follow-up
question: Some of the responses indicated that the Kaki glaze
normally would be used over another glaze whose flux would darken the
Kaki to Temmoku in some places. I have seen references both to a
clear glaze and to a celedon (Lee's recipe below for a light green
clear sounds as though it would have characteristics of both). Are
there any other suggestions for a good glaze to use under Kaki? (I am
firing ^6 oxidation.)
Again, my grateful thanks for all your help.
Arthur Lee
Englewood, Florida
--- In clayart@yahoogroups.com, Lee Love wrote:
>
> On 3/18/07, Michael McDowell wrote:
>
> > that. I am a little surprised that there hasn't been a good cone
6 recipe
> > offered here on the list. I would attribute that to the fact that
your first
> > post wasn't all that clear about just what you want to do, and to
the fact
> > that many members are distracted with NCECA right now.
>
> It may be problematic trying to duplicate this glaze at
cone
> 6 temps because of the high amount of iron (more than tenmoku) and
the
> fact that fluxing the glaze turns it into tenmoku, while keeping it
> stable for functional us. But too, if you are willing to fire to
> cone 8 or 9, it works fine in electric.
>
> Our closest counterpart to Mashiko Kaki is Albany slip.
> One way to go may be to use the Reeve Synthetic Kaki and do a Currie
> grid, adjusting flux and iron.
>
> Below is the transparent glaze I used under Reeve Mashiko when I
> worked in St. Paul (I found my old post in Google)*
>
> Lee Love on mon 6 may 02
>
>
> ----- Original Message -----
> From: "Lesley Alexander"
>
> > You mention they always put a limestone glaze under Kaki...
> > interesting. Could you give an example of a limestone glaze?
What does
> > this do? Thanks, Lesley
>
> Hi Lesley. The standard glaze at the workshop is nami jiro,
basically
> half ballclay and half wood ash, with kaolin added (5 to
20%,
> depending on the
> area of the kiln.) For use under the kaki, a different glaze
> is used: choseki
> nami jiro. It is a different formula, including feldspar. You
get the
> best kaki color with this glaze under it.
>
> Back home, I used something I got from Shirley Johnson: L G
Clear
> (light green clear.) Here is the recipe. I believe it is a
> variation of the
> Leach cone 8 1234, adjusted for cone 9/10:
>
> Custer 27
> OM4 14
> Whiting 20.5
> Flint 31.5
> Kaolin 7
>
>
> Lee in Mashiko
> .___________________________________________________
> | Lee Love ^/(o\| Practice before theory.
> | Ikiru@... |\o)/v - Sotetsu Yanagi - |
> `~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~'
>
>
> --
> Lee in Mashiko, Japan
> Minneapolis, Minnesota USA
> http://potters.blogspot.com/
>
> "To affect the quality of the day, that is the highest of arts." -
> Henry David Thoreau
>
> "Let the beauty we love be what we do." - Rumi
>
>
______________________________________________________________________
________
> Send postings to clayart@...
>
> 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@...
>
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