The Shelfords on thu 24 jul 97
June, Ron, whoever knows -
I'm wondering if this "fattening up" phenomenon that you mention is one of
the problems with the Floating blue recipe (has lots of GB) when used in
multiple layers - too thick, drips, etc. Is the only way around it REALLY
to let it dry and then reconstitute? What a first-class pain! Maybe one
should be more organized and make all the items for that glaze at one time,
then use up the glaze at one time, just after mixing. Anything to get past
the too thick drips problem, which is the only flaw with this otherwise
useful standby.
- Veronica
Re: >I think the big problem with Ghastly Borate and Colemanite is that
fact that
>the glaze fattens up because of gases released when the glaze sits for a long
>time. The only way to counter-act that, I understand, is to let the glaze dry
>out totally and then re-add water and mix. The release of the gases makes the
>glaze fatten up and seem too thick.
____________________________________________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
____________________________________________________________________________
June Perry on fri 25 jul 97
Dear Veronica:
I'm not sure if the problem you are experiencing is the classic problem that
can occur with glazes with large amounts of gerstley borate. Some of these
glazes, when left standing too long thicken up. I once read somewhere that is
had to do with gases forming. Someone wrote me after I said that and
disagreed with that. So for whatever reason, this does occur in some glazes
containing high amounts of gerstley borate that have been sitting around too
long. What happens is that the potter sees the too thick glaze and adds more
water to thin it out in order to get their normal application. But upon
firing, finds that the resultant glaze coating is too thin. The only way that
I know to correct the problem with such a batch, it is let it totally dry out
and then re-constitute it (another suggestion I read somewhere). :-)
If you think you have this problem then you may either want to make smaller
atches of the glaze that can be used in a few months or reformulate the glaze
using a oron frit.
Warm regards,
June
Ron Roy on sun 27 jul 97
I don't know - I am having some problems with an old c10 glaze of mine - no
GB and am "washing" it. I suspect there is a solubility problem simply
because the glaze (some of it) has been in that bucket for 10 years. Anyway
- washing a glaze - put lots of extra water in the glaze, stir well, let
settle for a day or two - then syphon off the clear water - every time you
do it you remove some of the solubles.
Reducing the amount of GB in a glaze is a simple matter using frit 3134 or
some such - post me the glaze and I will do it for the list.
>----------------------------Original message----------------------------
>June, Ron, whoever knows -
>I'm wondering if this "fattening up" phenomenon that you mention is one of
>the problems with the Floating blue recipe (has lots of GB) when used in
>multiple layers - too thick, drips, etc. Is the only way around it REALLY
>to let it dry and then reconstitute? What a first-class pain! Maybe one
>should be more organized and make all the items for that glaze at one time,
>then use up the glaze at one time, just after mixing. Anything to get past
>the too thick drips problem, which is the only flaw with this otherwise
>useful standby.
>- Veronica
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
The Shelfords on sat 9 aug 97
Ron Roy wrote:
>Reducing the amount of GB in a glaze is a simple matter using frit 3134 or
>some such - post me the glaze and I will do it for the list.
This was in reference to my earlier question:
>>I'm wondering if this "fattening up" phenomenon that you mention is one of
>>the problems with the Floating blue recipe (has lots of GB) when used in
>>multiple layers - too thick, drips, etc. Is the only way around it REALLY
>>to let it dry and then reconstitute?
Ron - Sorry to be slow to respond to this, I had put it aside to answer,
then got behind on the mail.
I think the fattening up problem really must be the GB, as when I have
ground off the occasional drip at the bottom, the structure of the glass is
full of bubbles.
You probably have the Floating Blue recipe already, but as it seems to be a
stand-by for a lot of people on the list, your offer to do a replacement of
some or all of the GB with frit 3134 would probably be received with
general interest and gratitude. Anyway, in case you don't have it, it is:
Floating Blue (cone 6 ox.)
47.3 Neph Sy
27 Gerstley Borate
20.3 Flint
5.4 EPK
2 Red Iron Ox.
1.2 Cobalt Ox.
4 Rutile
Thanks VERY much.
- Veronica
____________________________________________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
____________________________________________________________________________
cobbeldi on sat 9 aug 97
To anyone interested in Floating blue--since the last discussion on
floating blue, I did some testing substituting Frit 3134 for the Gerstley
Borate and so far the preliminary results have been promising. Her is the
substitution recipe that I came up with usin Hogg's glaze program:
Nepheline Syenite 43.26 g.
Silica 10.26g.
EPK Kaolin 13.67g.
Frit 3134 32.81g.
Red Iron Oxide 2.0 g.
Cobalt Oxide 1.0g.
Rutile 4.0g.
Epsom salts 2.0g. (this keeps the Frit from settling in the bucket to a
substance resembling cement)
If anyone has any other results from this, I'd be interested in hearing
about it.
Debra in Alabama-------
> ----------------------------Original message----------------------------
> Ron Roy wrote:
>
> >Reducing the amount of GB in a glaze is a simple matter using frit 3134
or
> >some such - post me the glaze and I will do it for the list.
>
> This was in reference to my earlier question:
> >>I'm wondering if this "fattening up" phenomenon that you mention is one
of
> >>the problems with the Floating blue recipe (has lots of GB) when used
in
> >>multiple layers - too thick, drips, etc. Is the only way around it
REALLY
> >>to let it dry and then reconstitute?
>
> Ron - Sorry to be slow to respond to this, I had put it aside to answer,
> then got behind on the mail.
> I think the fattening up problem really must be the GB, as when I have
> ground off the occasional drip at the bottom, the structure of the glass
is
> full of bubbles.
> You probably have the Floating Blue recipe already, but as it seems to be
a
> stand-by for a lot of people on the list, your offer to do a replacement
of
> some or all of the GB with frit 3134 would probably be received with
> general interest and gratitude. Anyway, in case you don't have it, it is:
>
> Floating Blue (cone 6 ox.)
>
> 47.3 Neph Sy
> 27 Gerstley Borate
> 20.3 Flint
> 5.4 EPK
> 2 Red Iron Ox.
> 1.2 Cobalt Ox.
> 4 Rutile
>
> Thanks VERY much.
>
> - Veronica
>
>
____________________________________________________________________________
> Veronica Shelford
> e-mail: shelford@island.net
> s-mail: P.O. Box 6-15
> Thetis Island, BC V0R 2Y0
> Tel: (250) 246-1509
>
____________________________________________________________________________
>
Ron Roy on mon 11 aug 97
Hi Debra in Alabama,
You have now seen my revisions so .......
I am wondering why we have such different results in our calculations.
I suspect we are working with different analysis of Ger Borate - I am
including two I got from Hammill and Gillespie. The first one is quite old
- cera 1992 is when I entered it into Insight
The second one I just got but notice I got another exactly the same in in
May 94.
If yours are significantly different you may want to update your files.
Gers Borate 5/92
----------------
B2O3................ 28.30 42.89%
Na2O................ 4.70 7.12%
SiO2................ 9.80 14.85%
Fe2O3............... .35 .53%
AL2O3............... 1.30 1.97%
MgO................. 3.50 5.30%
CaO................. 17.90 27.13%
K2O................. .14 .21%
----------
65.99
FORMULA & ANALYSIS
------------------
*CaO........ .36 19.09%
*MgO........ .10 3.73%
*K2O........ .00 .15%
*Na2O....... .09 5.01%
Fe2O3...... .00 .37%
*B2O3....... .46 30.18%
AL2O3...... .01 1.39%
SiO2....... .18 10.45%
COST/KG 5.06
L.O.I. 29.62
RATIO 12.82
EXPAN 506.23
WEIGHT 105.37
Current analysis from H&G
Gers Borate 9/97
----------------
B2O3................ 27.68 39.86%
Na2O................ 4.29 6.18%
SiO2................ 11.73 16.89%
Fe2O3............... .48 .69%
AL2O3............... 1.63 2.35%
MgO................. 4.19 6.03%
CaO................. 19.06 27.45%
K2O................. .38 .55%
----------
69.44
FORMULA & ANALYSIS
------------------
*CaO........ .37 19.39%
*MgO........ .11 4.26%
*K2O........ .00 .39%
*Na2O....... .08 4.36%
Fe2O3...... .00 .49%
*B2O3....... .43 28.16%
AL2O3...... .02 1.66%
SiO2....... .21 11.93%
COST/KG 5.12
L.O.I. 29.35
RATIO 12.23
EXPAN 511.53
WEIGHT 107.46
>----------------------------Original message----------------------------
>To anyone interested in Floating blue--since the last discussion on
>floating blue, I did some testing substituting Frit 3134 for the Gerstley
>Borate and so far the preliminary results have been promising. Her is the
>substitution recipe that I came up with usin Hogg's glaze program:
>Nepheline Syenite 43.26 g.
>Silica 10.26g.
>EPK Kaolin 13.67g.
>Frit 3134 32.81g.
>Red Iron Oxide 2.0 g.
>Cobalt Oxide 1.0g.
>Rutile 4.0g.
>Epsom salts 2.0g. (this keeps the Frit from settling in the bucket to a
>substance resembling cement)
>
>If anyone has any other results from this, I'd be interested in hearing
>about it.
>Debra in Alabama-------
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
cobbeldi on tue 12 aug 97
Thank you for the analysis on Gerstley Borate. When I get off the net, I
will pull up Hogg's program and see what I entered for Gerstley Borate. If
my memory is correct, Hogg's program will come up with more than one
revision for a glaze. I only "asked" for the one and I tested it. I was
very pleased with the test results so I did not go back to the program for
any more revisions. The color was much brighter, I did not get pieces of
the glaze falling onto the kiln shelf, the glaze had lots of surface
interest, and I did not have the crawling problems even where the glaze was
thick. I am going to try your revisions and see what results I get from
them, too.
If I find a difference in the GB analysis, I will let you know.
----------
> ----------------------------Original message----------------------------
> Hi Debra in Alabama,
>
> You have now seen my revisions so .......
>
> I am wondering why we have such different results in our calculations.
>
> I suspect we are working with different analysis of Ger Borate - I am
> including two I got from Hammill and Gillespie. The first one is quite old
> - cera 1992 is when I entered it into Insight
> The second one I just got but notice I got another exactly the same in in
> May 94.
>
> If yours are significantly different you may want to update your files.
>
> Gers Borate 5/92
> ----------------
> B2O3................ 28.30 42.89%
> Na2O................ 4.70 7.12%
> SiO2................ 9.80 14.85%
> Fe2O3............... .35 .53%
> AL2O3............... 1.30 1.97%
> MgO................. 3.50 5.30%
> CaO................. 17.90 27.13%
> K2O................. .14 .21%
> ----------
> 65.99
> FORMULA & ANALYSIS
> ------------------
> *CaO........ .36 19.09%
> *MgO........ .10 3.73%
> *K2O........ .00 .15%
> *Na2O....... .09 5.01%
> Fe2O3...... .00 .37%
> *B2O3....... .46 30.18%
> AL2O3...... .01 1.39%
> SiO2....... .18 10.45%
> COST/KG 5.06
> L.O.I. 29.62
> RATIO 12.82
> EXPAN 506.23
> WEIGHT 105.37
>
> Current analysis from H&G
>
> Gers Borate 9/97
> ----------------
> B2O3................ 27.68 39.86%
> Na2O................ 4.29 6.18%
> SiO2................ 11.73 16.89%
> Fe2O3............... .48 .69%
> AL2O3............... 1.63 2.35%
> MgO................. 4.19 6.03%
> CaO................. 19.06 27.45%
> K2O................. .38 .55%
> ----------
> 69.44
> FORMULA & ANALYSIS
> ------------------
> *CaO........ .37 19.39%
> *MgO........ .11 4.26%
> *K2O........ .00 .39%
> *Na2O....... .08 4.36%
> Fe2O3...... .00 .49%
> *B2O3....... .43 28.16%
> AL2O3...... .02 1.66%
> SiO2....... .21 11.93%
> COST/KG 5.12
> L.O.I. 29.35
> RATIO 12.23
> EXPAN 511.53
> WEIGHT 107.46
>
>
> >----------------------------Original message----------------------------
> >To anyone interested in Floating blue--since the last discussion on
> >floating blue, I did some testing substituting Frit 3134 for the Gerstley
> >Borate and so far the preliminary results have been promising. Her is
the
> >substitution recipe that I came up with usin Hogg's glaze program:
> >Nepheline Syenite 43.26 g.
> >Silica 10.26g.
> >EPK Kaolin 13.67g.
> >Frit 3134 32.81g.
> >Red Iron Oxide 2.0 g.
> >Cobalt Oxide 1.0g.
> >Rutile 4.0g.
> >Epsom salts 2.0g. (this keeps the Frit from settling in the bucket to
a
> >substance resembling cement)
> >
> >If anyone has any other results from this, I'd be interested in hearing
> >about it.
> >Debra in Alabama-------
>
>
>
> Ron Roy
> Toronto, Canada
> Evenings, call 416 439 2621
> Fax, 416 438 7849
> Studio: 416-752-7862.
> Email ronroy@astral.magic.ca
> Home page http://digitalfire.com/education/people/ronroy.htm
>
Richard Burkett on wed 13 aug 97
Ron Roy says about the Floating Blue glaze calculations:
>I am wondering why we have such different results in our calculations.
>I suspect we are working with different analysis of Ger Borate ...
That's pretty likely, and I'd like to suggest a couple of other factors
that may enter in: first, as has been mentioned here many times, gerstley
borate varies so much from batch to batch as to make this a non-issue.
Secondly, if you are trying to make sense of this using glaze calculation,
you might actually WANT to use an older analysis of gerstley borate (circa
the last time you bought some) instead of the latest analysis. That's one
of the other reasons I started the materials database on the CeramicsWeb -
to make older materials analyses available if needed.
I did the same calculations in a couple of minutes using HyperGlaze, and
got very close to the same recipe (#4) as Ron (but starting with an older
analysis of gerstley borate for the original unity molecular formula).
If anyone cares (feel free to tune out now, yawn) here are some other
possibilities for completeness (although the possible variations are close
to infinite - see #3 & 4).
Chemically these are almost identical In theory, in actuality they're all
likely to be slightly different when fired. Happy testing.
Original unity molecular formula:
Unity Formula for Floating Blue:
0.090 K2O 0.514 Al2O3 3.537 SiO2
0.388 Na2O 0.439 B2O3 6.9:1 Si:Al Ratio
0.424 CaO 0.004 Fe2O3
0.098 MgO
Estimated thermal expansion: 78.76x10-7/deg. C
Percentage Analysis for Floating Blue:
59.63 % SiO2
14.71 % Al2O3
8.56 % B2O3
2.39 % K2O
6.74 % Na2O
6.68 % CaO
1.12 % MgO
0.17 % Fe2O3
Revisions:
*** remember to add these colorants to all:
Rutile 4.00 %
Red Iron Oxide 2.00 %
Cobalt Oxide 1.20 %
Glaze name: Floating Blue rev. 1
Cone: 6
Recipe: Amount
Ferro frit 3134 23.11
Ferro frit 3195 14.06
Nepheline Sy. 39.55
EPK 9.72
Talc 1.12
Flint 12.44
Total: 100.00
Comments:
Molecular Formula:
0.479 KNa0 0.514 Al2O3 3.537 SiO2
0.424 CaO 0.439 B2O3 0.002 TiO2
0.034 MgO 0.002 Fe2O3
Glaze name: Floating Blue Rev. 2
Cone: 6
Recipe: Amount
Ferro frit 3134 22.73
Ferro frit 3195 13.82
Nepheline Syenite 38.88
EPK 9.56
Magnesium Carbonate 2.15
Flint 12.86
Total: 100.00
Comments:
Molecular Formula:
0.479 KNa0 0.514 Al2O3 3.537 SiO2
0.419 CaO 0.439 B2O3 0.002 TiO2
0.098 MgO 0.002 Fe2O3
Glaze name: Floating Blue rev. 3
Cone: 6
Recipe: Amount
Gerstley borate (1997) 14.60
Ferro frit 3134 16.81
Nepheline Syenite 41.94
EPK 9.86
Flint 16.06
Magnesium Carbonate 0.73
Total: 100.00
Comments: you can probably omit the Mag. carb.
Molecular Formula:
0.480 KNa0 0.514 Al2O3 3.537 SiO2
0.445 CaO 0.439 B2O3 0.002 TiO2
0.098 MgO 0.004 Fe2O3
Glaze name: Floating Blue rev. 4 (Re Ron Roy)
Cone: 6
Recipe: Amount
Gerstley borate (1997) 17.05
Ferro frit 3134 13.92
Nepheline Syenite 43.40
EPK 8.87
Flint 16.76
Total: 100.00
Comments:
Molecular Formula:
0.479 KNa0 0.514 Al2O3 3.537 SiO2
0.438 CaO 0.439 B2O3 0.002 TiO2
0.074 MgO 0.003 Fe2O3
Richard Burkett - School of Art, SDSU, San Diego, CA 92182-4805
E-mail: richard.burkett@sdsu.edu <-> Voice mail: (619) 594-6201
Home Page: http://rohan.sdsu.edu/dept/rburkett/www/burkett.html
CeramicsWeb: http://apple.sdsu.edu/ceramicsweb/
HyperGlaze@aol.com & http://members.aol.com/hyperglaze/
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