Dave Finkelnburg on fri 7 jun 02
Liz,
You can get a deep, translucent green at cone 6 in oxidation or mild
reduction by using about 6% copper carbonate in a glaze fluxed by boron and
calcium. The glaze, without the copper, should be clear, and not milky or
full of bubbles that could make it white. That's what's giving you the
turquoise.
As for your request for "...does not crackle," that depends entirely on
what clay you are putting the glaze on. Each clay body has its own, unique
coefficient of expansion. So does each clay. To avoid the crackle, you
need a clay body and glaze with about the same coefficient of expansion.
It would help to know if you use stoneware or porcelain clay. That
would at least give one a start. Porcelain typically has a much lower
coefficient of expansion than stoneware.
It's wonderful, by the way, that you and your students are enjoying
school. Sounds like a great learning environment!
Dave Finkelnburg in Idaho
From: Liz Lauter
>Does anyone have a bottle green cone 6 oxidation glaze? I want the kind of
>transparent deep blue green/olive green that pools, but does not crackle.
>I bought a beautiful rectangular platter at Pier One with a molded (or
>stamped) pattern of leaves on it, glazed with that dark green. Its puddling
>quality enhanced the impressed design.
>I thought that I found a copper green recipe, but instead the glaze is a
>beautiful deep turquoise crackle.
John and Judy Hesselberth on wed 12 jun 02
Hi Sam,
It must have been too much Christmas cheer! I don't have any
recollection of that glaze--can't recall having ever used anything like
it. Are you sure it was I? But on the other hand, glazes don't have to
add to 100 do they?
John
On Wednesday, June 12, 2002, at 01:05 PM, Maid O'Mud wrote:
> I got this off clayart 2.5 years ago, sent by John Hesselberth. Apply
> medium thin to white clay body for best results;
>
> Oil Spot Green/blue
>
> 50 3134
> 40 EPK
> 20 Silica
>
> 3 Cobalt Carb
> 5 Rutile
>
> Hey, John - I just noticed it doesn't add up to 100. Can you explain.
> Clayart message dated Dec 25 2000.
Liz Lauter on wed 12 jun 02
Hi Dave,
I'll look at my various clear glazes that I've tested in the past and try
them with copper.
I'm using B-Mix with sand, a Laguna stoneware for cone 5-6. Are you familiar
with it?
LIz
>From: Dave Finkelnburg
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: BOTTLE GREEN CONE 6 OX
>Date: Fri, 7 Jun 2002 19:05:09 -0600
>
>Liz,
> You can get a deep, translucent green at cone 6 in oxidation or mild
>reduction by using about 6% copper carbonate in a glaze fluxed by boron and
>calcium. The glaze, without the copper, should be clear, and not milky or
>full of bubbles that could make it white. That's what's giving you the
>turquoise.
> As for your request for "...does not crackle," that depends entirely
>on
>what clay you are putting the glaze on. Each clay body has its own, unique
>coefficient of expansion. So does each clay. To avoid the crackle, you
>need a clay body and glaze with about the same coefficient of expansion.
> It would help to know if you use stoneware or porcelain clay. That
>would at least give one a start. Porcelain typically has a much lower
>coefficient of expansion than stoneware.
> It's wonderful, by the way, that you and your students are enjoying
>school. Sounds like a great learning environment!
> Dave Finkelnburg in Idaho
>
>From: Liz Lauter
>
> >Does anyone have a bottle green cone 6 oxidation glaze? I want the kind
>of
> >transparent deep blue green/olive green that pools, but does not crackle.
> >I bought a beautiful rectangular platter at Pier One with a molded (or
> >stamped) pattern of leaves on it, glazed with that dark green. Its
>puddling
> >quality enhanced the impressed design.
> >I thought that I found a copper green recipe, but instead the glaze is a
> >beautiful deep turquoise crackle.
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
>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@pclink.com.
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Maid O'Mud on wed 12 jun 02
I got this off clayart 2.5 years ago, sent by John Hesselberth. Apply
medium thin to white clay body for best results;
Oil Spot Green/blue
50 3134
40 EPK
20 Silica
3 Cobalt Carb
5 Rutile
Hey, John - I just noticed it doesn't add up to 100. Can you explain.
Clayart message dated Dec 25 2000.
take care
Sam - Maid O'Mud Pottery
Melbourne, Ontario CANADA
"First, the clay told me what to do.
Then, I told the clay what to do.
Now, we co-operate."
sam 1994
http://www.ody.ca/~scuttell/
----- Original Message -----
From: "Liz Lauter"
To:
Sent: Friday, June 07, 2002 1:25 AM
Subject: BOTTLE GREEN CONE 6 OX
> Does anyone have a bottle green cone 6 oxidation glaze? I want the kind of
> transparent deep blue green/olive green that pools, but does not crackle.
> I bought a beautiful rectangular platter at Pier One with a molded (or
> stamped) pattern of leaves on it, glazed with that dark green. Its
puddling
> quality enhanced the impressed design.
> I thought that I found a copper green recipe, but instead the glaze is a
> beautiful deep turquoise crackle.
>
> Another question, why would some glazes crater in a firing, and others
not?
> What could I add to a glaze (cone 6 ox.) to stop the cratering?
>
> Would you believe that summer vacation is about to happen? I'm teaching
high
> school ceramics and I'm the only teacher at the whole school who isn't
dying
> to have a break. I'm having a blast with my students. Yesterday it was 97
> degrees and so the spray water bottles assumed a different importance. We
> do have our priorties straight in an academic environment.......
> Liz Lauter
> Instructor of Fun
> Liz Lauter
>
>
>
> _________________________________________________________________
> Chat with friends online, try MSN Messenger: http://messenger.msn.com
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> 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@pclink.com.
>
Carol Tripp on thu 13 jun 02
Sam wrote:
>I got this off clayart 2.5 years ago, sent by John Hesselberth. Apply
>medium thin to white clay body for best results;
>
>Oil Spot Green/blue
>
>50 3134
>40 EPK
>20 Silica
>
>3 Cobalt Carb
>5 Rutile
>
>Hey, John - I just noticed it doesn't add up to 100. Can you explain.
>Clayart message dated Dec 25 2000.
I am not sure whose recipe this is but it came up on Clayart ages ago during
a discussion of cobalt greens. The EPK should be 30 and some people found
that it was best to use some calcined EPK. It isn't a bottle green glaze
though. It's green where thin, brown where really thin, and blue/lavender
where thick and it is opaque. It can run and it can pinhole.
I would go for one of the base glazes in Ron & John's book with some copper
carb added in various amounts to arrive at a bottle green.
Best regards,
Carol
>
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Maid O'Mud on thu 13 jun 02
Carol wrote:
>
> I am not sure whose recipe this is but it came up on Clayart ages ago
during
> a discussion of cobalt greens. The EPK should be 30 and some people found
> that it was best to use some calcined EPK. It isn't a bottle green glaze
> though. It's green where thin, brown where really thin, and blue/lavender
> where thick and it is opaque. It can run and it can pinhole.
> I would go for one of the base glazes in Ron & John's book with some
copper
> carb added in various amounts to arrive at a bottle green.
> Best regards,
> Carol
> >
Hi Carol:
I printed off the e-mail dated dec 25 2000 and I did the receipe exactly as
printed - not even thinking about the addition discrepancy. For me, on iron
bearing clay, I get deep blue with oil spotting, and on white clay, I get a
lovely bottle green. I do not calcine my epk (too damn lazy ;-). I'm
guessing I got a good result by basically "screwing up". I don't use it on
the interior of vessels, so I don't worry about the durability of the glaze.
Perhaps RR or JH can jump in?? BTW, JH quotes the source as Lee Bedford
from April, 1999.
take care
Sam - Maid O'Mud Pottery
Carol Tripp on fri 14 jun 02
Hi Sam,
I was in the potters.org archives this morning looking for something else
and ended up in the Greens section (you know how that goes) and found Cindy
Strnad's Forest Green ^6ox
50 Frit 3134
25 silica
25 epk
1.0 chrome oxide
0.5 cobalt carb
She says this is glossy forest green that needs to be thick but if too
thick, it will run.
All variations on a theme but without the cobalt green factor.
BTW, don't you have crawling problems with high EPK glazes if you don't use
calcined epk?
Best regards,
Carol
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Ron Roy on mon 17 jun 02
The expansion on this glaze is kinda low - best to do the freezing /boiling
water test to make sure it won't be a pot buster with the clays you use. If
you need details on how to do this test let me know.
RR
>Hi Sam,
>I was in the potters.org archives this morning looking for something else
>and ended up in the Greens section (you know how that goes) and found Cindy
>Strnad's Forest Green ^6ox
>50 Frit 3134
>25 silica
>25 epk
>1.0 chrome oxide
>0.5 cobalt carb
>She says this is glossy forest green that needs to be thick but if too
>thick, it will run.
>All variations on a theme but without the cobalt green factor.
>BTW, don't you have crawling problems with high EPK glazes if you don't use
>calcined epk?
>Best regards,
>Carol
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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