Charles Moore on sun 15 feb 04
Randy,
I ran the two recipes through Insight Glaze Calculation and have printed
them below. Since we cannot send attachments through Clayart, I had to use
"cut & paste" to show the two recipes. That means that the formatting
(columns) will not be neatly reproduced. I can make some guesses about the
results of subbing 25% Gerstley for 25% of Frit 3134. Your fluxes, though
close, do add some Magnesium. Your silica in the second glaze is lower and
the silica/alumina ratio is lower, suggesting a less glossy glaze. And the
expansion is just a bit lower. (Let one of the glaze experts comment on
that.) As Alisa says in her reply, Frit 3134 is not a direct substitute.
Still you may have a workable glaze; you can only test.
And use CMC to make brushing easier.
Charles Moore
=========================================
=========================================
Recipe #1 Recipe #2
FRIT 3134................... 50.00 FRIT 3134...................
25.00
EPK Kaolin.................. 25.00 EPK Kaolin..................
25.00
Silica...................... 25.00
Silica...................... 25.00
========= Gerstley Borate.............
25.00
100.00
=========
100.00
CaO 0.68* 10.46 11.83
MgO 0.00* 0.03 0.04 CaO 0.70*
12.30 13.93
K2O 0.00* 0.09 0.06 MgO 0.09*
1.14 1.79
Na2O 0.31* 5.35 5.48 K2O 0.01*
0.23 0.16
TiO2 0.00 0.10 0.08 Na2O 0.20*
3.99 4.09
Al2O3 0.35 9.78 6.09 TiO2 0.00
0.10 0.08
B2O3 0.63 11.97 10.91 Al2O3 0.34
11.05 6.88
P2O5 0.00 0.06 0.03 B2O3 0.61
13.36 12.20
SiO2 3.76 61.96 65.42 P2O5 0.00
0.07 0.03
Fe2O3 0.00 0.21 0.08 SiO2 3.04
57.41 60.70
Fe2O3 0.01 0.35 0.14
Cost: 2.49
Calculated LOI: 3.48 Cost:
1.33
Imposed LOI: Calculated LOI:
9.98
Si:Al: 10.75 Imposed LOI:
SiB:Al: 12.54 Si:Al:
8.82
Thermal Expansion: 366.75 SiB:Al:
10.59
Formula Weight: 364.57 Thermal Expansion:
342.77
Formula Weight:
318.22
Date: 2/14/04
Codenumber: Date:
2/14/04
ID: 143 Codenumber:
Location: ID:
142
---- Original Message -----
From: "Alisa Clausen"
To:
Sent: Sunday, February 15, 2004 12:46 AM
Subject: Re: Adjusting a Glaze/Frit 3134 for G.B?
> got a glaze from Chris Schafale. The base is
> > 3134 50%
> > Kaolin 25%
> > Silica 25%
>
>
> Dear Randy, Chris,
> As we know, this glaze is the classic G.B. "easy clear" which is colored
to
> make other well known glazes, like Randi's red, etc. (I have seen a
version
> of Randi's Red with Feldspar and Talc).
> Subbing the Frit 3134 gives another analysis, but how does it look
compared
> to the G.B. version?
>
> A while back there was discussion surrounding the May-June article in PMI,
> where a recipe for Maria's Blue was given with 24 G.B. or Frit 3134.
> Irresponsible because it will not make the same glaze and gives the idea
> that these materials are interchangeable. This perked my ears because I
had
> been subbing G.B. with a local frit for experimental interest. The glazes
> were fine in appearance, but since I have not used a calculation program
> yet, I could not answer for what I would assume is the vast difference in
> the actual analysis of the glazes. So, we have too glazes that have
similar
> appearances, but are two different glazes.
>
> Subbing 50% of a glaze with a Frit 3134 could give the same melt, same
> appearance, but it would be interesting to know what glaze (analysis)
> results. If it is stable according to John and Ron's limits. I
navigating
> around the GlazeMaster program so maybe soon I can begin to answer my own
> questions.
>
> regards from Alisa in Denmark
>
>
____________________________________________________________________________
__
> 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.
Alisa Clausen on sun 15 feb 04
got a glaze from Chris Schafale. The base is
> 3134 50%
> Kaolin 25%
> Silica 25%
Dear Randy, Chris,
As we know, this glaze is the classic G.B. "easy clear" which is colored to
make other well known glazes, like Randi's red, etc. (I have seen a version
of Randi's Red with Feldspar and Talc).
Subbing the Frit 3134 gives another analysis, but how does it look compared
to the G.B. version?
A while back there was discussion surrounding the May-June article in PMI,
where a recipe for Maria's Blue was given with 24 G.B. or Frit 3134.
Irresponsible because it will not make the same glaze and gives the idea
that these materials are interchangeable. This perked my ears because I had
been subbing G.B. with a local frit for experimental interest. The glazes
were fine in appearance, but since I have not used a calculation program
yet, I could not answer for what I would assume is the vast difference in
the actual analysis of the glazes. So, we have too glazes that have similar
appearances, but are two different glazes.
Subbing 50% of a glaze with a Frit 3134 could give the same melt, same
appearance, but it would be interesting to know what glaze (analysis)
results. If it is stable according to John and Ron's limits. I navigating
around the GlazeMaster program so maybe soon I can begin to answer my own
questions.
regards from Alisa in Denmark
Randy McCall on sun 15 feb 04
I don't have a glaze program either so it would be interesting to see how
the formula differs. I will let you know how it tests out. It seems in the
80's I used this formula totally with GB and it worked fine. I got out of
pottery and now am back in and sort of starting over.
Thanks for the response.
Randy
----- Original Message -----
From: "Alisa Clausen"
To:
Sent: Sunday, February 15, 2004 3:46 AM
Subject: Re: Adjusting a Glaze/Frit 3134 for G.B?
> got a glaze from Chris Schafale. The base is
> > 3134 50%
> > Kaolin 25%
> > Silica 25%
>
>
> Dear Randy, Chris,
> As we know, this glaze is the classic G.B. "easy clear" which is colored
> to
> make other well known glazes, like Randi's red, etc. (I have seen a
> version
> of Randi's Red with Feldspar and Talc).
> Subbing the Frit 3134 gives another analysis, but how does it look
> compared
> to the G.B. version?
>
> A while back there was discussion surrounding the May-June article in PMI,
> where a recipe for Maria's Blue was given with 24 G.B. or Frit 3134.
> Irresponsible because it will not make the same glaze and gives the idea
> that these materials are interchangeable. This perked my ears because I
> had
> been subbing G.B. with a local frit for experimental interest. The glazes
> were fine in appearance, but since I have not used a calculation program
> yet, I could not answer for what I would assume is the vast difference in
> the actual analysis of the glazes. So, we have too glazes that have
> similar
> appearances, but are two different glazes.
>
> Subbing 50% of a glaze with a Frit 3134 could give the same melt, same
> appearance, but it would be interesting to know what glaze (analysis)
> results. If it is stable according to John and Ron's limits. I
> navigating
> around the GlazeMaster program so maybe soon I can begin to answer my own
> questions.
>
> regards from Alisa in Denmark
>
> ______________________________________________________________________________
> 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.
>
| |
|
