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carbon trapping and shino glazes

updated thu 31 jul 97

 

Peter and Sam Tomich on thu 3 jul 97

How do you know if a glaze is a shino glaze? What defines it: the
look? the ingredients? the firing? And what is carbon trapping. I'm
sorry, but I still don't get it. I have read how to do it, but what
does it look like?

Samantha Tomich
Earthen Vessel Pottery
Paauilo, Hawaii

Craig Martell on sat 5 jul 97

Hi Samantha:

Shino glazes and traditional Japanese Shino Ware came into being in the late
15th or early 16th century in the Mino region of Japan. Originally, the
ware was meant to in some way emulate the white porcelains of China. Until
this time, Japanese ceramics had been darker and more earthy. I believe
this was the first attempt at producing white ware in Japan.

The Shino glazes that one sees in the US are mostly glossy, fat, white
crackle glazes with some orange to red and dark red "fire color" which comes
from iron in the clay body, or iron slips under the glaze. I make
porcelain, so if I want to obtain the "fire color" I have to use iron
bearing slips, or load the glaze with kaolin which contains significant
amounts of iron and titanium. Shinos are fluxed with soda spars and
nepheline syenite and do not contain limestone (calcium), which will inhibit
the "fire color" by disolving the iron. Shinos usually do not have added
silica, the silica being contributed by the spars and the clays in the
glaze. Some Shinos contain Spodumene, which may be added to balance the
high expansion soda spars. I have seen lots of Shinos without Spod. that
have the true Shino appearance. One of the simplest shino receipes I know
of is: 70% Nepheline Syenite, 30% Kaolin.

What I like about Shinos is the warm, friendly, non pretentious character of
the glaze. Shinos crawl, craze, and pinhole in ways that are often extemely
decorative and pleasing in a textural sense. Shinos, I guess, are technical
and indusrrial renegades and give the ware that they adorn a relaxed
feeling. What shinos lack in "technical correctness", they balance with
wonderful aesthetic qualities. If I could assign a personality to Shinos, I
would probably say that they were like Whoopi Goldberg or Lyle Lovett maybe.
But really, the glazes true nature is hard to put into words. You just have
to look at a lot of shino pots and decide for yourself what they are and
what they mean to you.

Carbon Trapping is not a mandatory feature of Shinos and vice versa. The
trapped carbon leaves dark, shadowy areas in the glaze and is a totally
random, uncontrolled effect. Carbon trapping of course, is produced in a
reduction atmosphere as are shino glazes. I almost forgot to mention that.
Anyway, that's my grasp of some of this stuff. I'm sure others will send
posts and fill in all the gaps that I've left but I hope I've helped a little.

Kind Regards, Craig Martell-Oregon

Michelle H. Lowe on sat 5 jul 97

> ----------------------------Original message----------------------------
> How do you know if a glaze is a shino glaze? What defines it: the
> look? the ingredients? the firing? And what is carbon trapping. I'm
> sorry, but I still don't get it. I have read how to do it, but what
> does it look like?

Hi,
I can't tell you a whole lot about what exactly makes a shino a
shino, but I know what one is and shino is probably my personal
all-time favorite of all glazes. It is a finicky glaze, I find, as
testified by one pot I got that looks like globs of cottage cheese
all over the surface, I kept that one, probably can never repeat!

Carbon trapping is a gray to black trapping of color on the surface
of the glaze itself. The look of shino is orange to white, depending
on thickness.

To see some fairly good examples of carbon trapped shino you can go
to my web page, I did a woodfire workshop last Feb. with Jack Troy
and have some photos of the best shinos I got out of that firing.
I'll give you the direct url so you can bypass the intro pages.

http://www.amug.org/~mishlowe/woodfire

this is an index of photographs of pots from that workshop, and a few
of people involved, the kiln and the fired load before unloading.

The pics that show the shinosurface the best are-

woodpot1.jpg This one I dipped into shino and then waxed a design
right after the surface dried. The carbon trapping appears where the
wax *wasn't* and results in the wavy design you can see around the
pot. The carbon trapping is the gray/black surface you can see on
the upper 2/3 of the pot where the wax wasn't.

woodpot2.jpg This one is a wonderful example of carbon trapping on
most of the pot, except for the bottom 1/4, which is more like shino
without the carbon trapping.

woodpot8.jpg is similar to woodpot2, except it seems to have gotten
more ash on the upper, also carbon trapped part.

Hope you can go view these to give you a better idea :-)

Good luck!

Mishy, or should I signoff... Mishino!

LOL

Michelle Lowe, potter in the Phoenix desert \|/ |
mishlowe@indirect.com -O- | |
mishlowe@aztec.asu.edu /|\ | | |
|_|_|
http://www.amug.org/~mishlowe ____ |
-\ /-----|-----
( )
<__>

Jennifer Rhinesmith on mon 7 jul 97

Samantha, A Shino glaze comes from Japan. In Japanese the word Shino
means snow. It looks like snow melting over a muddy road. As far as the
carbon trapping goes, in a reduction firing the flame is burning
inefficiently and therefor produces high amounts of carbon(soot). This
falls on the pots, and when the glaze begins to melt it trapps the carbon
in the melting process. This is how it was explained to me. I hope this
makes cense. I really love the Shino that I use, Gustin's. Jennifer in
Alpine, TX jrhi479@wolf.sulross.edu

On Thu, 3 Jul 1997, Peter and Sam Tomich wrote:

> ----------------------------Original message----------------------------
> How do you know if a glaze is a shino glaze? What defines it: the
> look? the ingredients? the firing? And what is carbon trapping. I'm
> sorry, but I still don't get it. I have read how to do it, but what
> does it look like?
>
> Samantha Tomich
> Earthen Vessel Pottery
> Paauilo, Hawaii
>