Craig Martell on mon 2 nov 98
Hi:
The subject of shinos comes up on Clayart now and then so I thought that
there might be an interest in some tests that I've done recently. I've
always liked warm, fire colored shino glazes but I've not worked with them
enough or studied them to the point that I have a good understanding of how
they work.
I use a local slip clay or native stone that has a lot of Iron in it,
probably 8-9% and Jim Robinson asked me to send him some and we've been
talking about the possibility of this stone being used to make red shino
glazes. Jim's approach to shino reds is that you need a very high alumina
glaze to develop the red so he recommends using alumina oxide in shinos
instead of kaolin, which contributes silica as well as alumina, and silica
may discourage the development of shino red. Jim also suggests a combo of
kaolin and alumina oxide. Use a very fine mesh alumina though, say at least
200.
I ran an Ian Currie receipe blend using 70% nepheline syenite, 10%
spodumene, and 20% native stone for the fluxes. These were included in a
biaxial blend of 35 glazes blending alumina oxide and silica with the
fluxes. The pure flux mixture is in the bottom left corner of the 35 glaze
tile that looks like a waffle and the 7 glazes running up to the top left
corner show a line blend of alumina oxide with the fluxes, and no silica.
The glazes from the lower left, or pure flux corner that run to the right
side of the tile in the bottom row are a line blend of the fluxes with only
silica and no alumina. All the other glazes on the tile that move up and to
the right of the flux corner are blends of alumina and silica. I don't want
to type all night, so I'll leave some of the logic for you guys to imagine.
I think you probably see how this works. I should mention that the tiles
were made with my porcelain body and one set of glazes was placed on a tile
that had been sprayed with an iron slip. I might mention also that I used
an iron bearing stone in the fluxes to encourage the red and orange to
develop. You don't get much shino color on a porcelain body if there isn't
an iron slip underneath, or some iron in the glaze itself. Iron bearing
bodies will color a shino that has no added colorants.
The tiles were fired to cone 10 reduction, with reduction starting at cone
08 and maintained throughout the entire firing, even the half hour soak at
peak. Jim was right. The higher alumina glazes on the left side of the
tile were red shinos. As you went to the right side of the tile, which is
higher in silica, and towards the bottom of the tile, which is lower in
alumina, the red became hot orange and lightened as the alumina-silica ratio
exchanged dominance. The thing that really amazed me was that ALL 35 glazes
were fused into glass. The high aluminas were very viscous and showed a lot
of surface tension but they WERE glassy. This is due to a eutectic formed
by sodium and lithium, which is very important in the making of this type of
glaze. You need this strong eutectic in order to get the amount of alumina
into the glaze that is needed for the fire color and reds. Spodumene is the
lithium source and Nepheline Syenite contributes sodium. They are a good
choice for a eutectic because they are at different ends of the expansion
spectrum. Sodium being very high and lithium being low expansion. Shinos
will usually craze but I did get a few in the tiles that seem to fit, in the
high alumina and silica range. These were hot orange shinos.
I might also mention that the glazes that were higher in fluxes and lower in
alumina and silica showed a lot of carbon inclusion. There were some real
smoky, celedon looking glazes in the lower left of the tile. I ran another
biaxial using fluxes from Wirt's Carbon Trap, and didn't trap any carbon at
all!! Say What??
That's about it. I'd be glad to have some comments on this stuff, pro or
con, whatever is germaine, and I'd be glad to elaborate on any of this if
there are things I didn't write about or I missed.
regards, Craig Martell in Oregon
June Perry on wed 4 nov 98
Craig, if you get a pink/peach on your shinos, then you can get red from that
same recipe by changing your firing schedule.
I have a shino that can go anywhere from a very pretty peachy light orange, to
orange to a very dark reddish orange depending on how thinly I apply it and
how early I reduce and how heavily.
I think it was Ken Ferguson who said to reduce shinos very, very early to get
good red shino. I believe he starts around 1250. I have found that I can still
get the good deep red orange starting in the 1450 range in my Geil kiln.
My recipe doesn't have alumina oxide either. Here it is:
#1013 Graham's Shino, cone 10 Reduction (Peach to deep red orange) It calls
for chemical grade spodumene. I just use whatever my supplier had. Maybe it is
chemical grade??
NEPHELINE SYENITE 39.3
SPODUMENE(CHEMICAL GRADE) 30.6
KENTUCKY OM#4 BALL CLAY 17.2
SODA ASH 8.0
EDGAR PLASTIC KAOLIN 4.8 APPLY
QUITE THIN FOR PEACH AND RED
This fires well anywhere from a soft cone 10 to cone 11 around 2 o'clock, if I
remember. I usually five cone 10 with the tip falling between 2 and 5 o'clock,
but it's gotten away from me a couple of times. :-) I think it might be able
to go to a full cone 11. At the higher temperature it gets a lovely rich, wet
kind of look--shiny, but not glassy. It's more like a fat shine -- hard to
describe.
When I see Jim Robinson, I'll have to tell him about the red clay deposit we
have about 45 minutes north of him in Ramsey Canyon, in Gold Hill. In fact,
before we move to Ashland, if our house sale goes through, I want to go get me
a good sampling of that to test.
I also heard about an old porcelain factory that operated in this area around
the late 1800's to theturn of the century and a neighbor of my sons, who
unfortunately has moved back to Eugene, told me of finding some white clay in
a cave while roaming the mountains. He had promised to take me there, but got
a job in Eugene right after that and moved away. The family still owns the
land here, so he may be back one of these days. He and his dad are pretty free
spirits and often work for a while to get enough money to sustain them and
take long periods off. Next time he's down I hope to beg or bribe him to take
me to that cave. His dad is an old rock collector who know all the land
around here. In fact his dad told me about finding the old porcelain factory
in the mountains above Evans Creek. He said there wasn't much there anymore,
but I would love to scrounge around the site. I imagine the porcelain source
wouldn't be too far from the factory ruins. I remember that incredible
porcelain pit I saw in Japan. It looked like they had been digging it out for
a hundred years or more.
If you like to look for raw materials, there is a fairly new map that you can
get (have yet to get mine) for the state of Oregon that will show clay
deposits, etc. They didn't have it in yet at the Medford BLM office in Medford
a couple of years ago when I stopped in but told me I could send for it. I
think the geologist told me it was about ten dollars. I stopped in at the time
to ask where I could find some flagstone and she told me about some
decomposing granite rock up the road from me on Evans Creek road. I
formulated a mashiko type iron glaze with it and it was very intriguing -- not
brightish red like a mashiko, but more of a very deep almost blackish
burgundy. One of these days when we are settled, I may play around with it a
bit more, trying it in a celadon base. Right now I have to pack and get ready
for a big move as soon as these house inspections are over.
Warm regards,
June
JFTRT on wed 4 nov 98
Craig Martell-
This might not be the path you might select,
but the end might be useful.
Some time ago I had a student that was
not satisfied with the grey/light orange
shino pot that was fired to ^10 reduction,
so he refired, (against my recommendation,)
it to ^6 in an electric kiln. Well, that
pot turned out orange/red in color! And now
every time someone is disappointed with their
shino pot, we refire it to ^6 ox. and it
turns out those rich shades of color.
Our clay body is 2parts Goldart/1part AP Green f.c.
Todd Turek
Liz Willoughby on wed 4 nov 98
Hello Craig,
Thanks for sharing your results on your recent shino tests. Since I got my
Bailey 3 years ago, I've been primarily interested in shinos, mainly
Malcolm's Carbon Trap, but also have done quite a few tests taken from that
article by Jim Robinson in that Studio Potter published a few years ago.
I've also discovered that just changing my tests using a clay body with
some iron in it, makes my shino much redder. I mostly use a porcelain clay
body.
All this information about eutectics for the glaze melt is really
interesting, and I think I am finally beginning to understand what it all
means! Well, I'm going to have to get some 200m alumina, and do some
tests.
I am having real difficulty getting consistent results with the carbon
trapping that I like. After having two very successful firings with
gorgeous crystals last spring, I am getting a real mixed bag of results in
the same firing. Like sooty black to just orange or orange and white
splotches, which looks to me like the carbon has burnt out. I go into
reduction at 012, reduce heavily for 1 1/2 hours, then lighten up, but keep
it in reduction to the end. I'm considering getting an oxy probe. I have a
Bailey Kiln.
I assume that the carbon is trapped early on as the surface of the glaze
(due to the soda ash) is melting first...then does the glaze seal over the
carbon? and can the carbon disappear if you lose reduction? Can you
clarify for me what is really going on here?
Been discouraged, but your tests have sparked my interest again. (Malcolm
says that I am a member of good standing in the "Shino Shitty Club". You
can say that again.)
Regards, Liz
>----------------------------Original message----------------------------
>Hi:
>
>The subject of shinos comes up on Clayart now and then so I thought that
>there might be an interest in some tests that I've done recently. I've
>always liked warm, fire colored shino glazes but I've not worked with them
>enough or studied them to the point that I have a good understanding of how
>they work.
>
>I use a local slip clay or native stone that has a lot of Iron in it,
>probably 8-9% and Jim Robinson asked me to send him some and we've been
>talking about the possibility of this stone being used to make red shino
>glazes. Jim's approach to shino reds is that you need a very high alumina
>glaze to develop the red so he recommends using alumina oxide in shinos
>instead of kaolin, which contributes silica as well as alumina, and silica
>may discourage the development of shino red. Jim also suggests a combo of
>kaolin and alumina oxide. Use a very fine mesh alumina though, say at least
>200.
>
>I ran an Ian Currie receipe blend using 70% nepheline syenite, 10%
>spodumene, and 20% native stone for the fluxes. These were included in a
>biaxial blend of 35 glazes blending alumina oxide and silica with the
>fluxes. The pure flux mixture is in the bottom left corner of the 35 glaze
>tile that looks like a waffle and the 7 glazes running up to the top left
>corner show a line blend of alumina oxide with the fluxes, and no silica.
>The glazes from the lower left, or pure flux corner that run to the right
>side of the tile in the bottom row are a line blend of the fluxes with only
>silica and no alumina. All the other glazes on the tile that move up and to
>the right of the flux corner are blends of alumina and silica. I don't want
>to type all night, so I'll leave some of the logic for you guys to imagine.
>I think you probably see how this works. I should mention that the tiles
>were made with my porcelain body and one set of glazes was placed on a tile
>that had been sprayed with an iron slip. I might mention also that I used
>an iron bearing stone in the fluxes to encourage the red and orange to
>develop. You don't get much shino color on a porcelain body if there isn't
>an iron slip underneath, or some iron in the glaze itself. Iron bearing
>bodies will color a shino that has no added colorants.
>
>The tiles were fired to cone 10 reduction, with reduction starting at cone
>08 and maintained throughout the entire firing, even the half hour soak at
>peak. Jim was right. The higher alumina glazes on the left side of the
>tile were red shinos. As you went to the right side of the tile, which is
>higher in silica, and towards the bottom of the tile, which is lower in
>alumina, the red became hot orange and lightened as the alumina-silica ratio
>exchanged dominance. The thing that really amazed me was that ALL 35 glazes
>were fused into glass. The high aluminas were very viscous and showed a lot
>of surface tension but they WERE glassy. This is due to a eutectic formed
>by sodium and lithium, which is very important in the making of this type of
>glaze. You need this strong eutectic in order to get the amount of alumina
>into the glaze that is needed for the fire color and reds. Spodumene is the
>lithium source and Nepheline Syenite contributes sodium. They are a good
>choice for a eutectic because they are at different ends of the expansion
>spectrum. Sodium being very high and lithium being low expansion. Shinos
>will usually craze but I did get a few in the tiles that seem to fit, in the
>high alumina and silica range. These were hot orange shinos.
>
>I might also mention that the glazes that were higher in fluxes and lower in
>alumina and silica showed a lot of carbon inclusion. There were some real
>smoky, celedon looking glazes in the lower left of the tile. I ran another
>biaxial using fluxes from Wirt's Carbon Trap, and didn't trap any carbon at
>all!! Say What??
>
>That's about it. I'd be glad to have some comments on this stuff, pro or
>con, whatever is germaine, and I'd be glad to elaborate on any of this if
>there are things I didn't write about or I missed.
>
>regards, Craig Martell in Oregon
Liz Willoughby
R.R. 1
Grafton, Ontario
Canada. K0K 2G0
e-mail lizwill@phc.igs.net
Grimmer on thu 5 nov 98
Craig,
Fascinating post! I will run the same set using Yankee Hill Slip (from
KS, I think). What is your local slip or stone? I assume you have read Jim's
excellent article on shino from a few years back, 'Revival Fires: Another
face of Shino." It runs along the same lines as your post. You have added
some great details, tho.
steve grimmer
marion, illinois
----------
>From: Craig Martell
>To: CLAYART@LSV.UKY.EDU
>Subject: shino color
>Date: Mon, Nov 2, 1998, 1:25 PM
>
>----------------------------Original message----------------------------
>Hi:
>
>The subject of shinos comes up on Clayart now and then so I thought that
>there might be an interest in some tests that I've done recently. I've
>always liked warm, fire colored shino glazes but I've not worked with them
>enough or studied them to the point that I have a good understanding of how
>they work.
>
>I use a local slip clay or native stone that has a lot of Iron in it,
>probably 8-9% and Jim Robinson asked me to send him some and we've been
>talking about the possibility of this stone being used to make red shino
>glazes. Jim's approach to shino reds is that you need a very high alumina
>glaze to develop the red so he recommends using alumina oxide in shinos
>instead of kaolin, which contributes silica as well as alumina, and silica
>may discourage the development of shino red. Jim also suggests a combo of
>kaolin and alumina oxide. Use a very fine mesh alumina though, say at
least
>200.
>
>I ran an Ian Currie receipe blend using 70% nepheline syenite, 10%
>spodumene, and 20% native stone for the fluxes. These were included in a
>biaxial blend of 35 glazes blending alumina oxide and silica with the
>fluxes. The pure flux mixture is in the bottom left corner of the 35 glaze
>tile that looks like a waffle and the 7 glazes running up to the top left
>corner show a line blend of alumina oxide with the fluxes, and no silica.
>The glazes from the lower left, or pure flux corner that run to the right
>side of the tile in the bottom row are a line blend of the fluxes with only
>silica and no alumina. All the other glazes on the tile that move up and
to
>the right of the flux corner are blends of alumina and silica. I don't
want
>to type all night, so I'll leave some of the logic for you guys to imagine.
>I think you probably see how this works. I should mention that the tiles
>were made with my porcelain body and one set of glazes was placed on a tile
>that had been sprayed with an iron slip. I might mention also that I used
>an iron bearing stone in the fluxes to encourage the red and orange to
>develop. You don't get much shino color on a porcelain body if there isn't
>an iron slip underneath, or some iron in the glaze itself. Iron bearing
>bodies will color a shino that has no added colorants.
>
>The tiles were fired to cone 10 reduction, with reduction starting at cone
>08 and maintained throughout the entire firing, even the half hour soak at
>peak. Jim was right. The higher alumina glazes on the left side of the
>tile were red shinos. As you went to the right side of the tile, which is
>higher in silica, and towards the bottom of the tile, which is lower in
>alumina, the red became hot orange and lightened as the alumina-silica
ratio
>exchanged dominance. The thing that really amazed me was that ALL 35
glazes
>were fused into glass. The high aluminas were very viscous and showed a
lot
>of surface tension but they WERE glassy. This is due to a eutectic formed
>by sodium and lithium, which is very important in the making of this type
of
>glaze. You need this strong eutectic in order to get the amount of alumina
>into the glaze that is needed for the fire color and reds. Spodumene is
the
>lithium source and Nepheline Syenite contributes sodium. They are a good
>choice for a eutectic because they are at different ends of the expansion
>spectrum. Sodium being very high and lithium being low expansion. Shinos
>will usually craze but I did get a few in the tiles that seem to fit, in
the
>high alumina and silica range. These were hot orange shinos.
>
>I might also mention that the glazes that were higher in fluxes and lower
in
>alumina and silica showed a lot of carbon inclusion. There were some real
>smoky, celedon looking glazes in the lower left of the tile. I ran another
>biaxial using fluxes from Wirt's Carbon Trap, and didn't trap any carbon at
>all!! Say What??
>
>That's about it. I'd be glad to have some comments on this stuff, pro or
>con, whatever is germaine, and I'd be glad to elaborate on any of this if
>there are things I didn't write about or I missed.
>
>regards, Craig Martell in Oregon
Donn Buchfinck on thu 5 nov 98
hey
I am looking for a shino recipie that is called porcelain shino c10
anyone have this recipie??
Donn
Vince Pitelka on fri 6 nov 98
>I am looking for a shino recipie that is called porcelain shino c10
>anyone have this recipie??
Donn -
This is the one I have. It's a beauty, especially in wood-fire. When
applied thinly it gives a lustrous golden orange shino.
Porcelain Shino - ^10 Reduction
Spodumene 30
EPK 5
Soda Ash 8
Neph Sy 39
Ball Clay 17
Good luck -
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Craig Martell on mon 9 nov 98
> What is your local slip or stone? I assume you have read Jim's
>excellent article on shino from a few years back, 'Revival Fires: Another
>face of Shino." It runs along the same lines as your post. You have added
>some great details, tho.
>steve grimmer
Hello Steve and thanx for the post:
The stone I use comes from a river that runs through the Cascade Range,
which is volcanic. We are theorizing that the parent material is probably a
mixture of basalt and andesite which are both rich in iron. Might be from a
palagonite tuff though. The geological formation is called The Breitenbush
Tuff. We are trying to find some papers that have been done on this
material to avoid paying for an analysis. I may have to call Ray, my
mineralogy prof from school, not the Ray that Jeff Lawrence is nurturing on
reds.
I have to say too that all this info I've sent on shinos is Jim's work.
He's been tutoring me on shino glazes and I have to give him credit for all
the logic and creative thinking. I am merely a sponge. Also Ian Currie for
his info on shinos, through conversations, e-mail, and his book.
I'll be interested in hearing how your stone pans out in shinos!
later, Craig Martell-Oregon
Ron Roy on tue 10 nov 98
I remember reading about this somewhere - high alumina glazes - like shino
- cannot hold iron in suspension very well - so it tends to come to the
surface and reoxidize to red - certainly the refiring described below would
help this process - at least helping to reoxidize the iron to red - RR
>----------------------------Original message----------------------------
>Craig Martell-
>This might not be the path you might select,
>but the end might be useful.
>Some time ago I had a student that was
>not satisfied with the grey/light orange
>shino pot that was fired to ^10 reduction,
>so he refired, (against my recommendation,)
>it to ^6 in an electric kiln. Well, that
>pot turned out orange/red in color! And now
>every time someone is disappointed with their
>shino pot, we refire it to ^6 ox. and it
>turns out those rich shades of color.
>Our clay body is 2parts Goldart/1part AP Green f.c.
>
>Todd Turek
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
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