Chris Greenman on mon 5 jun 06
I have been getting lots of rude nasty bubbles in my shino glazes. It is not
specific to clay bodies and seems to be mostly in my kiln at home. I fire a
20 cuft. downdraft with two power burners. I am now trying to keep the
forced air at a minimum. THis has seemed to help but still does not get all
the bubbles away. I have searched the archives several times to get ideas.
Some people have suggested bisqing lower--I bisque at 04 but why wouldn't
other glazes be affected? I have also tried saoking at the end of the firing
and also have tried firing down- restriking at 1900. I should also mention
that I reduce heavy to get nice blacks in shino.
Anyway I would be glad to hear of any ideas to resolve this problem.
TIA
Chris Greenman
cgreenman3@knology.net
Lee Love on mon 5 jun 06
Shino can be pretty stiff and can take more temp that other glazes.
Put it in your hottest spot. If you have to, you can try adding
more Neph Sye.
I bisque at 012 and lower in my wood kiln. I don't think a
lower bisque with help your pinholing problem, but sponging might.
You could combine two things: adding more flux while sponging.
Wear rubber gloves and dip your sponge in either a soda ash solution
or in the water on top of your shino and sponge the bisque that is
going to get shino on it.
Also, I used to treat the feet of non-shino pots to get a blush
on the foot that reminds you of woodfiring.
--
Lee In Mashiko, Japan
http://mashiko.org
http://seisokuro.blogspot.com/
"The way we are, we are members of each other. All of us.
Everything. The difference ain't in who is a member and who is not,
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craig edwards on mon 5 jun 06
Hello Chris: This might help-- or not. I have gotten some bubbles in shinos
by reducing to early. If I start reducing before 010 sometimes I get some
foamy sorts of bubbles that refiring will not take care of.
~Craig Edwards
On 6/5/06, Chris Greenman wrote:
>
> I have been getting lots of rude nasty bubbles in my shino glazes. It is
> not
> specific to clay bodies and seems to be mostly in my kiln at home. I fire
> a
> 20 cuft. downdraft with two power burners. I am now trying to keep the
> forced air at a minimum. THis has seemed to help but still does not get
> all
> the bubbles away. I have searched the archives several times to get ideas.
> Some people have suggested bisqing lower--I bisque at 04 but why wouldn't
> other glazes be affected? I have also tried saoking at the end of the
> firing
> and also have tried firing down- restriking at 1900. I should also mention
> that I reduce heavy to get nice blacks in shino.
>
> Anyway I would be glad to hear of any ideas to resolve this problem.
>
> TIA
>
> Chris Greenman
> cgreenman3@knology.net
>
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
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Russel Fouts on tue 6 jun 06
I don't see anything wrong with pin-holing or crawling in a shino
(blistering is another thing). Some of the most wonderful shinos I've
seen are full of pin-holes and terrifically crawled.
I covet an Eric Wong shino teabowl or platter. I have wonderfully
richly textured shino cups from Lisa Hammond (new work) and yesterday
bought a beauty from Pascal Geoffroy.
Long live crawly, pin-holy shinos!
Russel
Russel Fouts
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Susan Coville on tue 6 jun 06
Hi Chris, I have had only minimal experience with Shino and I have used it almost exclusively in gas soda firings. My understanding is that shino is a carbontrap glaze. This may be part or all of the reason for your bubbles. My insticts would have led me on the path to fire slower, and fire down, to slow the cooling time as you have done. But my main action would be to slow the firing up time, allowing for any impurities to escape before the carbon trap activity happens and/or slow near the maturing temp much longer to this same end.
As I said before, I have not had much experience with shino and only one formula in particular, anderson ranch shino, which is a wonderful formula, with delicious results. I would be happy to send this recipe on once I am back in my studio in a week or 2, if you would like?
Also, could you explain the bubble effect a bit more.? is it pinholing or is it trapped bubbles, unbroken or is it some other surface effect? A special coloration? What clay are you using? That would help in the diagnosis.
And contrary to other suggestions, I would bisque at a higher temp, in the event there is a clay body gas/substance that can't escape before the glaze seals. The higher bisque would drive off more impurities or gasses prior to glaze. also, have you tried to refire some of the unpeasant pieces to see if anything changed?
One more idea... You could try no body reduction and a lighter glaze reduction (or none at all), since the carbon trap quality of this glaze kinda does this on its own.
Let me know how it goes... Susan
Chris Greenman wrote:
I have been getting lots of rude nasty bubbles in my shino glazes. It is not
specific to clay bodies and seems to be mostly in my kiln at home. I fire a
20 cuft. downdraft with two power burners. I am now trying to keep the
forced air at a minimum. THis has seemed to help but still does not get all
the bubbles away. I have searched the archives several times to get ideas.
Some people have suggested bisqing lower--I bisque at 04 but why wouldn't
other glazes be affected? I have also tried saoking at the end of the firing
and also have tried firing down- restriking at 1900. I should also mention
that I reduce heavy to get nice blacks in shino.
Anyway I would be glad to hear of any ideas to resolve this problem.
TIA
Chris Greenman
cgreenman3@knology.net
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Lee Love on wed 7 jun 06
On 6/7/06, Russel Fouts wrote:
> I don't see anything wrong with pin-holing or crawling in a shino
> (blistering is another thing). Some of the most wonderful shinos I've
> seen are full of pin-holes and terrifically crawled.
Pinholing is usually desireable, especially on the trimmed areas of
the foot. I thought the original poster was concerned abyt a kind
of pinholing that is not acceptable, like the type that are craters
with sharp edges.
--
Lee in Mashiko, Japan
http://mashiko.org
My google Notebooks:
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