Paulette Carr on mon 11 nov 02
A couple of weeks ago a Mason Stain underglaze formula (Harold Deeley's) was
republished with the following formula:
<
Glaze Type: Underglaze formula (measured in parts)
Components:
F-4 Soda Spar 20
Kaolin 10
Ball Clay 5
Frit (3124) 10
Stain 40
Liquid 75
Liquid Components:
Anti-freeze 1000cc
Water 1000cc
CMC Liquid 500cc ...>>>
I am interested in using underglazes at Cone 9, with and without a clear
glaze on top of it. I am concerned that this formula was meant to be used at
lower temperatures, and that the resulting underglaze may overflux at cone 9.
Does anyone have any experience with this underglaze formula at high fire
temperatures, or thoughts on this and what I might substitute for the
frit/feldspar, ratios, etc.
Thanks, in advance, for your help!
My best,
Paulette Carr
St. Louis, MO
iandol on tue 12 nov 02
Dear Paulette Carr,=20
You have every right to be suspicious. The first question I ask is "Why =
is that ingredient there?"
I would be suspicious about the Frit in that recipe. This assist in =
fusion during the bisque firing but perhaps it has a low fusion =
temperature in relationship to bisque firing temperatures. This may =
reduce the degree to which your bisque body adsorbs water when glaze is =
applied over your underglaze decoration. The result will be thinner =
glaze, even a degree of roughness when your work is fired to maturity.
It will be interesting to learn what the others have to say.
Best regards,
Ivor Lewis
David Hendley on tue 12 nov 02
An "underglaze" without a clear glaze on top of it is really no different
than a "glaze", wouldn't you say?
Treated as a glaze, this recipe will make a very stiff cone 9 glaze, with
1.30 molecular equivalents of alumina, way over the limit formula,
as well as more silica than a usual cone 9 glaze.
There is no way will this be overfluxed unless the added stain melts at
a low temperature. This is not likely, as most stains are, in fact,
pretty refractory.
Remember that if you use anti-freeze you want to use non-toxic
propylene glycol, not ethylene glycol.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
----- Original Message -----
>
> Glaze Type: Underglaze formula (measured in parts)
> Components:
> F-4 Soda Spar 20
> Kaolin 10
> Ball Clay 5
> Frit (3124) 10
>
> Stain 40
> Liquid 75
>
> Liquid Components:
> Anti-freeze 1000cc
> Water 1000cc
> CMC Liquid 500cc ...>>>
>
> I am interested in using underglazes at Cone 9, with and without a clear
> glaze on top of it. I am concerned that this formula was meant to be used
at
> lower temperatures, and that the resulting underglaze may overflux at cone
9.
> Does anyone have any experience with this underglaze formula at high fire
> temperatures, or thoughts on this and what I might substitute for the
> frit/feldspar, ratios, etc.
Ron Roy on wed 13 nov 02
Hi Paulette,
I just compared the recipe (I wonder if parts means by weight) by parts by
weight - with a common cone 6 glaze - it has three times the alumina and
1.7 times the silica so - by itself it will not be overfired at cone 9.
There is a chance that some stains might overflux it enough at 40% so the
best answer - aside from contacting Mason - would be to test it first.
RR
>A couple of weeks ago a Mason Stain underglaze formula (Harold Deeley's) was
>republished with the following formula:
>
><>
>Glaze Type: Underglaze formula (measured in parts)
>Components:
>F-4 Soda Spar 20
>Kaolin 10
>Ball Clay 5
>Frit (3124) 10
>
>Stain 40
>Liquid 75
>
>Liquid Components:
>Anti-freeze 1000cc
>Water 1000cc
>CMC Liquid 500cc ...>>>
>
>I am interested in using underglazes at Cone 9, with and without a clear
>glaze on top of it. I am concerned that this formula was meant to be used at
>lower temperatures, and that the resulting underglaze may overflux at cone 9.
> Does anyone have any experience with this underglaze formula at high fire
>temperatures, or thoughts on this and what I might substitute for the
>frit/feldspar, ratios, etc.
>
>Thanks, in advance, for your help!
>
>My best,
>Paulette Carr
>St. Louis, MO
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Paulette Carr on wed 13 nov 02
Thank you for responding, Ivor.
Your point is well taken, and is something about which I am concerned. David
Hendley has assured me that "this recipe will make a very stiff cone 9 glaze,
with
1.30 molecular equivalents of alumina, way over the limit formula,
as well as more silica than a usual cone 9 glaze." I will wait another few
days for responses/discussion. My hunch was to change the feldspar to
potash, and reduce the amount of frit - some is probably needed to increase
adhesion early in the firing. If no one else responds, then I plan to make
up some of the underglaze as specified in the (Deeley) recipe, and test with
and without a clear glaze on top of the brushing. When I have finished my
testing, I will post my results.
In a message dated 11/12/02 11:39:44 PM, iandol@tell.net.au writes:
<< Dear Paulette Carr,
You have every right to be suspicious. The first question I ask is "Why is
that ingredient there?"
I would be suspicious about the Frit in that recipe. This assist in fusion du
ring the bisque firing but perhaps it has a low fusion temperature in
relationship to bisque firing temperatures. This may reduce the degree to
which your bisque body adsorbs water when glaze is applied over your
underglaze decoration. The result will be thinner glaze, even a degree of
roughness when your work is fired to maturity.
It will be interesting to learn what the others have to say.
Best regards,
Ivor Lewis >>
In a message dated 11/11/02 11:48:44 AM, PAGCarr writes:
<< <
Glaze Type: Underglaze formula (measured in parts)
Components:
F-4 Soda Spar 20
Kaolin 10
Ball Clay 5
Frit (3124) 10
Stain 40
Liquid 75
Liquid Components:
Anti-freeze 1000cc
Water 1000cc
CMC Liquid 500cc ...>>>
I am interested in using underglazes at Cone 9, with and without a clear
glaze on top of it. I am concerned that this formula was meant to be used at
lower temperatures, and that the resulting underglaze may overflux at cone 9.
Does anyone have any experience with this underglaze formula at high fire
temperatures, or thoughts on this and what I might substitute for the
frit/feldspar, ratios, etc.
Thanks, in advance, for your help!
My best,
Paulette Carr
St. Louis, MO
>>
iandol on thu 14 nov 02
Dear Ron Roy,
I'm not sure if this answer <common cone 6 glaze - it has three times the alumina and 1.7 times the =
silica so - by itself it will not be overfired at cone 9. >> addresses =
the question
The recipe in question is a carrier medium for the stain, to be mixed =
with a stain to act as a flux which will adhere the stain to the work =
when it is applied and as it is fired, which I presume is before being =
fired to bisque.=20
I read the original post to mean the mixture was a carrier recipe, a =
dilutent or a fixative. Perhaps Paulette would confirm that?
Best regards,
Ivor.
| |
|
