[Clayart] Shino and Spodumene

Robert Harris robertgharris at gmail.com
Tue Jan 4 18:02:49 UTC 2022


VInce - I honestly thought you just hadn't thought about it. I know I often
say something which is true for one context, but not more broadly.  And
with Morgan being something of an expert in some Japanese pottery I've
always assumed you knew quite a bit about Japanese glazes. I admit, I made
the assumption you know a lot more about everything and just hadn't tied
the pieces together.

You're right, of course, most (all?) shino recipes we have here have
spodumene and soda ash in them.

It also depends on what you define as a "shino"! (Arguably some of the
snowflake crackle glazes would be shinos under the right circumstances).

In general, I think that Western recipes are a lot more complicated than
those in Japan or many parts of China, where they're still often using the
old traditional methods of a bit of this rock, and bit of that ash, and
maybe some clay. And spodumene is a pretty unusual rock so anything vaguely
traditional isn't going to contain spodumene. (It's also my understanding
that the vast majority of Japanese potters don't make their own glazes,
there is often a village "glaze master" or store, that makes up big batches
for all the potteries in the area. That may just be in the more famous
centers like Mashiko.).

My understanding (and Hank Murrow probably knows a lot more about this than
I do) is that Japanese shinos are still something like 80% of a feldspathic
rock, 15% kaolin and maybe some ash (which if unwashed would contain quite
a bit of potassium or sodium carbonate). From what I've seen online, most
of what they call shino seems to be whiter and often matt-er than ours with
a lot more pinholing. Obviously they get iron blushing and carbon trapping,
but I think it's a lot rarer and harder to control than the western shinos.

I certainly think that a lot of what we like about "American Shinos" (which
is not my description BTW), could be replicated without the spodumene.
They're not going to be identical, of course, but maybe that's not a bad
thing!

Rob


On Tue, 4 Jan 2022 at 06:25, <vpitelka at dtccom.net> wrote:

> Hi Robert -
> You give me credit for knowing more than I do.  I know a lot, but when I
> make a mistake or unintentionally post misleading information on Clayart,
> someone responds expressing surprise and implying that I should have known
> better.  I appreciate their confidence in me, but I'm only human.  I
> remember one of those silly placards pinned up in offices that said, "To
> err is human.  Must you be so human?"
>
> I guess I don't have any Japanese shino recipes.  I checked all my shino
> recipes and they all contained spodumene.  I'll look into this further,
> because I'd like to introduce more shinos into my soda firings.   I might
> even be able to do it without any American affectations.
> - Vince
>
> Vince Pitelka
> Potter, Writer, Teacher
> Chapel Hill, NC
> vpitelka at dtccom.net
> www.vincepitelka.com
> https://chathamartistsguild.org/
>
> -----Original Message-----
> From: Clayart <clayart-bounces at lists.clayartworld.com> On Behalf Of
> Robert Harris
> Sent: Monday, January 3, 2022 9:02 PM
> To: Clayart international pottery discussion forum <
> clayart at lists.clayartworld.com>
> Subject: Re: [Clayart] HAPPY NEW YEAR CLAYART
>
> Come on, Vince, sometimes you say things that are truly puzzling.
>
> No Japanese shino (you know, actual real shinos) has spodumene in it (as
> far as I am aware).
>
> Spodumene is an American affectation. Pretty much the only reason it's
> included is to reduce the amount of crazing that's induced by the soda ash
> (which again is an American affectation). Low melt spodumene (which was
> really amblygonite) was handy because of its low melting point, but that
> hasn't been available for years. I bet you could replace spodumene with
> NephSy and some kaolin, you'd just have to put up with more crazing.
>
> I wonder if you could replace the soda ash with borax if the crazing is
> bothersome. It would almost certainly alter the results somewhat, but it
> would allow the techniques that use the solubility of soda ash to decorate
> pots.
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