Louis Katz on tue 26 apr 05
Would help to send the recipe you are using. Don't forget the
temperature.
BTW I have had problem where an iron glaze went green gold but I need
more information to see if you situation might be similar
Louis
On Apr 26, 2005, at 1:27 PM, dennis mclaughlin wrote:
> From time to time I've had a problem with my Shaner's Red glaze. When
> it is first mixed using 5.5% iron I get an even rich red color with
> very little gold green in the areas where it is thick. The surface is
> semi-matt almost satin like appearance. As the glaze sits in the
> bucket usually over a month's time it changes both in color and in
> surface showing more green and also becoming dull matt. It doesn't
> want to coat the pot as evenly when it its dipped. Where its thinner
> its black much less attractive.
> Is there a chemical change that is taking place? If so can it be
> prevented. Sometimes I end up throwing the glaze out and starting
> with a new batch which is a real waste.
> Has anyone else had this problemA?
> Denny
> birchcouleepottery@yahoo.com
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.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.
>
>
Louis Katz
Question Questioning
Donalson on tue 26 apr 05
We had an "incident" with a 30 gallon garbage can of Shaner's Red last =
week at NAU. The large glaze bucket had not been used for several months =
and when the tight fitting plastic lid was removed to blunge the glaze =
there was a stench that was literally too nasty for words. The entire =
studio was evacuated and it was a good thirty minutes before anyone =
reentered the building. We think that the natural bone ash Don Bendel =
had squirreled away since the mid seventies was the olfactory offender. =
There was for certain a chemical reaction taking place in that can of =
glaze. Perhaps the breakdown of the bone ash or whatever is causing the =
rotten egg smell is partially responsible in some way for the change in =
the fired glaze.
Just a thought.
Craig AZ
Victoria E. Hamilton on tue 26 apr 05
Hi Dennis -
I've used Shaner's Red for years - never had that problem. Can you post
your recipe? It might help for the analysis. Also, how heavy, and how long
do you reduce?
Vicki Hamilton
Millennia Antica Pottery
Seattle, WA
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of dennis
mclaughlin
Sent: Tuesday, April 26, 2005 11:28
To: CLAYART@LSV.CERAMICS.ORG
Subject: Problems with Shaner's Red
From time to time I've had a problem with my Shaner's Red glaze. When it is
first mixed using 5.5% iron I get an even rich red color with very little
gold green in the areas where it is thick. The surface is semi-matt almost
satin like appearance. As the glaze sits in the bucket usually over a
month's time it changes both in color and in surface showing more green and
also becoming dull matt. It doesn't want to coat the pot as evenly when it
its dipped. Where its thinner its black much less attractive.
Is there a chemical change that is taking place? If so can it be prevented.
Sometimes I end up throwing the glaze out and starting with a new batch
which is a real waste.
Has anyone else had this problemA?
Denny
birchcouleepottery@yahoo.com
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.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.
dennis mclaughlin on tue 26 apr 05
From time to time I've had a problem with my Shaner's Red glaze. When it is first mixed using 5.5% iron I get an even rich red color with very little gold green in the areas where it is thick. The surface is semi-matt almost satin like appearance. As the glaze sits in the bucket usually over a month's time it changes both in color and in surface showing more green and also becoming dull matt. It doesn't want to coat the pot as evenly when it its dipped. Where its thinner its black much less attractive.
Is there a chemical change that is taking place? If so can it be prevented. Sometimes I end up throwing the glaze out and starting with a new batch which is a real waste.
Has anyone else had this problemA?
Denny
birchcouleepottery@yahoo.com
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Steve Irvine on wed 27 apr 05
Denny,
That recipe is very similar to the one I've been using off and on for the past 35 years. I've never
really noticed the problem you're having. One difference is that I usually use a sodium type
feldspar when I make it up, and I also add 2% bentonite. I also usually toss in a handfull of wood
ash when I mix it up since I like a slightly more gold tone to it. It still goes warm red in the thinner
applications. The branch bottle in the middle of my home page is an example.
My guess is that the problem could be traced back to something going on with the bone ash, since
this is that ingredient that is helping to develop the orangey red colour that the glaze is famous
for. Could you try some tests with it using bone ash from a different supplier? For several years
I've been using something called "bone ash substitute" or diabasic calcium phosphate. It smells
like laundry soap when added to a glaze and I've never had the fermenting problem mentioned in
an earlier post in this thread. It has the formula of: 2CaO.P2O5.5H2O compared to the usual
formula for bone ash of: 3CaO.P2O3 Extra whiting has to be added to the glaze to make up for
the difference.
David Shaner once told me that he would occasionally get an angry letter from a potter because
the glaze didn't turn out properly, as if it were his fault! So maybe there are a few other potters
out there who've had this problem.
Hope this helps.
Steve Irvine
http://www.steveirvine.com
>Here is the recipe. I have fired pots together some glazed with the batch when it was first mixed
and some later on and there is a definite difference
>
>Denny
>
>Custer Feldspar 49
>EPK 23
>Whiting 20
>Talc 4
>Bone Ash 4
>
>RIO 5.5%
dennis mclaughlin on wed 27 apr 05
Here is the recipe. I have fired pots together some glazed with the batch when it was first mixed and some later on and there is a definite difference
Denny
Custer Feldspar 49
EPK 23
Whiting 20
Talc 4
Bone Ash 4
RIO 5.5%
Louis Katz wrote:Would help to send the recipe you are using. Don't forget the
temperature.
BTW I have had problem where an iron glaze went green gold but I need
more information to see if you situation might be similar
Louis
On Apr 26, 2005, at 1:27 PM, dennis mclaughlin wrote:
> From time to time I've had a problem with my Shaner's Red glaze. When
> it is first mixed using 5.5% iron I get an even rich red color with
> very little gold green in the areas where it is thick. The surface is
> semi-matt almost satin like appearance. As the glaze sits in the
> bucket usually over a month's time it changes both in color and in
> surface showing more green and also becoming dull matt. It doesn't
> want to coat the pot as evenly when it its dipped. Where its thinner
> its black much less attractive.
> Is there a chemical change that is taking place? If so can it be
> prevented. Sometimes I end up throwing the glaze out and starting
> with a new batch which is a real waste.
> Has anyone else had this problemA?
> Denny
> birchcouleepottery@yahoo.com
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.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.
>
>
Louis Katz
Question Questioning
______________________________________________________________________________
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.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Dale Neese on thu 28 apr 05
I use a glaze with similar ingredients. Glaze application and thickness,
bisque temperature as well as using "real" bone ash vs. tri-calcium
phosphate can cause the glaze to look differently from each firing. I find
that a thinner application is better for intended color while a thick
application turns the glaze color a duller greenish-red matt. Check the
viscosity of the glaze for consistency. Thin and stir completely before
applying. I bisque fire a low iron stoneware clay body to cone 08. I
reduction fire to cone 10 flat, long cooling period helps also.
Dale Tex
"across the alley from the Alamo"
San Antonio, Texas USA
Louis Katz on thu 28 apr 05
Hi Denny
I would try it with a precipitated whiting and see if the problem
dissappears.
Louis
BTW My recipe for this glaze has more bone ash:
Glaze Name: Shaner Red
Cone: 10
Base Glaze: Pct
Kaolin 22.09
Custer Feldspar 46.45
Whiting 18.82
Talc 3.55 284
Bone Ash 9.09
TOTALS: 100.00
Also add these colorants and additions:
Rutile 1.00
RIO 4.00
On Apr 27, 2005, at 11:19 AM, dennis mclaughlin wrote:
> Here is the recipe. I have fired pots together some glazed with the
> batch when it was first mixed and some later on and there is a
> definite difference
>
> Denny
>
>
>
>
> Custer Feldspar 49
> EPK 23
> Whiting 20
> Talc 4
> Bone Ash 4
>
> RIO 5.5%
>
| |
|
