UNI_ POTTER on sun 11 jan 98
There has been some discussion of this glaze lately. But I haven't tried it myse
yet. My copy of Bernard Leach's "A Potter's Book" states:
China clay 10
Limestone 20
Quartz 30
Feldspar 40
Colors warm in oxidation, cold in reduction.
Fires to cone 8. Potters here have used this recipe to create a cone 9/10 glaze
follows:
EPK 10
Whiting 20
Flint, fine mesh 30
Custer (potash spar) 40
+ plus iron, etc. %
I don't know if this is viable in unity formula or not. This glaze is no doubt a
old as the hills so who cares. Try running your computer glaze program with thes
materials and see if you can adjust percentages to get a similar yet viable bale
glaze. Unity formulas don't always make good glazes and some of the best glazes,
so I've been told, are non-conforming ones. I think the main idea is to get repe
predictable results. Precision in measurement and use of identical materials is
to achieve this. I have been working on this lately. Here are some more:
Higby's 1-2-3 (cone 08)
Gerstley Borate 30
EPK 20
Flint 10
Hey! That doesn't add up to 100! How about this:
1-1-1 (Cone 10)
Dolomite 1
Feldspar 1
EPK 1
I'm going to try to test these glazes, the high fire ones anyway, and see what h
I need some good simple basic glazes. Some of these kinds of glazes may have co
from running triaxial blends, rather than unity calculations (maybe?)
Eric Hansen, Lawrence, Ks. (Sunny, cold, bright out)
Free web-based email, Forever, From anywhere!
http://www.mailexcite.com
Louis Katz on mon 12 jan 98
------------------
Call it self promotion if you must, but again I find myself compelled
to submit the following simple recipe to the list.
Katz 111
1 whiting
1 Silica
1 kaolin
Cone 10 reduction.
Unity Formula for Katz 111:
=CA 1CaO=CA 0.365 Al2O3 2.415 SiO2=CA
=CA 6.6:1 Si:Al Ratio
This one sit right near the Calcium Alumina Silica Eutectic(read
lowest nmelting point of Calcium Alumina and Silica) and pretty close
to 1234. Works too, can't say that I use it on pots though.
This is a good glaze to experiment with. It is simple to calculate,
and simple to change the ratios of. Try substituting dolomite for some
of the whiting. Try decreasing the clay. Add Iron oxide and see if the
glaze flows more. Try adding silica.
Louis
Ron Roy on tue 13 jan 98
The Higby glaze is unbalanced at any cone - and - even though the B2O3
content is over 12% - making it difficult to predict expansion - it is way
low - Just so some testing with this to see if what ever you are making is
going to survive you glaze/clay combination.
The 111 glaze is way short of silica at cone 10 and oversupplied with MgO.
The calculated expansion tells me it will craze on most bodies. If I add
enough silica to make it a durable glaze the expansion becomes too low.
You all know how I feel about simple glazes - to be concerned about
simplicity - well if I had to list the factors I was going to be concerned
about if I wanted to make glazes I like and solve the other factors like
durability and fit - simplicity would not make the list - complexity would.
This may all sound like I'm trying to beat up those who like the idea of
simple glazes - not so - everyone is entitled to their opinion - I just
wish some one would point out the logic of simple glazes - and why do some
potters think they are worth making. Surely it can't be as simple as _ they
are easy to remember _ or they are easy to weigh out?
>Higby's 1-2-3 (cone 08)
>Gerstley Borate 30
>EPK 20
>Flint 10
>
>Hey! That doesn't add up to 100! How about this:
>
>1-1-1 (Cone 10)
>Dolomite 1
>Feldspar 1
>EPK 1
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
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
Ron Roy on tue 13 jan 98
Hey Louis - that's prety good - probably fit a lot of bodies too - but it's
not oatmeal - I mean it's not durable - short of silica and oversupplied
with CaO.
>----------------------------Original message----------------------------
>------------------
>Call it self promotion if you must, but again I find myself compelled
>to submit the following simple recipe to the list.
>
>Katz 111
>1 whiting
>1 Silica
>1 kaolin
>
>Cone 10 reduction.
>
>Unity Formula for Katz 111:
> 1CaO 0.365 Al2O3 2.415 SiO2
>
> 6.6:1 Si:Al Ratio
>
>This one sit right near the Calcium Alumina Silica Eutectic(read
>lowest nmelting point of Calcium Alumina and Silica) and pretty close
>to 1234. Works too, can't say that I use it on pots though.
>This is a good glaze to experiment with. It is simple to calculate,
>and simple to change the ratios of. Try substituting dolomite for some
>of the whiting. Try decreasing the clay. Add Iron oxide and see if the
>glaze flows more. Try adding silica.
>
>
>Louis
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
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
Louis Katz on wed 14 jan 98
------------------
Simplicity,
I like simple glazes. I also like complicated ones. Given my
druthers(sp?) I would opt for complicated ingredients and simple
formulas such as the following.
ork Opaque Cone: 10
Testing: TestedSurface texture: shiny glossy
Firing: Ox. or Red.
Recipe: Percent Batch
Albany Slip 100.00 100.00
Totals: 100.00 =25 100.00 gm
Unity Formula for New York Opaque:
0.157 K2O=CA 0.662 Al2O3 4.431 SiO2=CA
0.060 Na2O 0.148 Fe2O3 0.046 TiO2=CA
0.477 CaO=CA 6.7:1 Si:Al Ratio
0.306 MgO=CA
Percentage Analysis:
63.58 =25 SiO2
16.13 =25 Al2O3
3.54 =25 K2O
0.88 =25 Na2O
6.40 =25 CaO
2.94 =25 MgO
5.64 =25 Fe2O3
0.88 =25 TiO2
At the same time If I was trying to make a living making pots I would
have some glazes in my repetoire that have a wide range of fluxes.
Glazes with multiple fluxes seem to have wider firing temperatures. I
worked at a summer camp in Michigan with a salt kiln for eight summers
and one glaze never failed to melt or act properly. It was a simple
recipe. It worked until our last bag of old Custer disappeared.
A couple recipes that seemed to always work (20 years ago). please
excuse the formating.
Glaze name: O'Reilly White
Cone: 10
Recipe: Percent Batch
F-4 2.85 228
Custer Feldspar 49.65 3972
Dolomite 8.00 640
Whiting 8.80 704
EPK 5.65 452
Zinc Oxide 3.55 284
Petalite 3.30 264
Opax 6.15 492
Bar Carb(use 1=25Strontium Carbonate as substitute)
1.20 96
Flint 10.85 868
Totals: 100.00 =25 8000 Gm
Also add:
Bentonite 3.00 240
(optional)Managanese Dioxide 2.50 200
Unity Formula for O'Reilly White:
0.171 K2O=CA 0.362 Al2O3 2.784 SiO2=CA
0.089 Na2O 0.146 ZrO2=CA
0.429 CaO=CA 7.7:1 Si:Al Ratio
0.137 MgO=CA
0.016 Li2O
0.019 BaO=CA
0.140 ZnO=CA
Percentage Analysis:
58.04 =25 SiO2
12.81 =25 Al2O3
5.59 =25 K2O
1.91 =25 Na2O
8.37 =25 CaO
1.91 =25 MgO
0.17 =25 Li2O
1.01 =25 BaO
3.96 =25 ZnO
6.25 =25 ZrO2
Glaze name: Wiser Honey
Cone: 10
Recipe: Percent Batch
Custer Feldspar 63.00 5040
Dolomite 13.30 1064
Flint 1.90 152
Ball Clay 4.40 352
Whiting 3.20 256
Zinc Oxide 3.20 256
Petalite 4.50 360
Zircopax 6.50 520
Totals: 100.00 =25 8000 Gm
Also add:
Bentonite 2.00 160
Rutile 3.20 256
Unity Formula for Wiser Honey:
0.207 K2O=CA 0.387 Al2O3 2.749 SiO2=CA
0.096 Na2O 0.003 Fe2O3 0.003 TiO2=CA
0.331 CaO=CA 0.108 ZrO2=CA
0.223 MgO=CA 7.1:1 Si:Al Ratio
0.019 Li2O
0.124 ZnO=CA
Percentage Analysis:
58.50 =25 SiO2
14.00 =25 Al2O3
6.91 =25 K2O
2.13 =25 Na2O
6.59 =25 CaO
3.19 =25 MgO
0.21 =25 Li2O
3.58 =25 ZnO
0.18 =25 Fe2O3
0.07 =25 TiO2
4.71 =25 ZrO2
But , If you are still reading, simplicity and complexity have many
sides. The more ingredients you have the more there are that can screw
you up. It's just that each ingredient will screw you up a little bit
less intensely.d
Because your car sometimes fails to start it might be sensible to have
a spare, but having three spares is probably more trouble tha it is
worth.
Hey Just MHO
Louis working when he should be working
John Post on thu 15 jan 98
At 07:46 AM 1/13/98 EST, you wrote:
>----------------------------Original message----------------------------
>>Higby's 1-2-3 (cone 08)
>>Gerstley Borate 30
>>EPK 20
>>Flint 10
>>
>>Hey! That doesn't add up to 100!
>The Higby glaze is unbalanced at any cone - and - even though the B2O3
>content is over 12% - making it difficult to predict expansion - it is way
>low - Just so some testing with this to see if what ever you are making is
>going to survive you glaze/clay combination.
Ron,
The Higby's 1-2-3 glaze is a Raku glaze and is made by volume and not by
weight. When I run the numbers for it, I get something that looks like
this...
Recipe by volume:
Flint 1
EPK 2
Gerstley borate 3
Na2O 0.16 Al2O3 0.35 SiO2 2.11
MgO 0.16 B2O3 0.75
CaO 0.68
Alumina:Silica ratio is 1.00 : 6.08
Neutral:Acid ratio is 1.00 : 1.93
Alkali:Neutral:Acid ratio is 1.00 : 1.09 : 2.11
Expansion coefficient: 66.8 x 10e-7 per degree C
Oxides causing abnormal expansion effects: B2O3
I think you'll agree that the numbers look a little better this way. For a
raku glaze it seems to have an adequate amount of silica. While I agree
that mixing glazes by volume isn't nearly as precise as weighing them out,
this one always works ok for me. I usually measure it out in cups.
Considering the variable nature of the gerstley, I think that this seat of
the pants/pants pockets approach to measuring is the way to go for this
glaze.
BTW I have learned a great deal of information about the chemistry involved
in glazes from your postings as well as the postings of Tony, Craig and
Tom. I am sure that there are countless others on this list benefiting
from the wealth of information you all share so freely. Thanks!
John Post
jp6mchp@moa.net
Ron Roy on fri 16 jan 98
Hi John - thanks for the additional info - I think you should post thst to
the list - i am concerned that otheres may not have all the info they need
for this glaze.
I am including my calculation based on your additioal info - would you be
so kind as to weigh your cups so we can verify we are working with the
right data - i am still concerned about the low expansion possibilities - I
usually aim for 450 and this one is still way low at 296.91 - I do agree
that the numbers are reasonable this way.
Untitled Recipe 2
-----------------
Gers Borate 9/97.... 55.50 55.50%
SILICA.............. 19.00 19.00%
EPK................. 25.50 25.50%
----------
100.00
FORMULA & ANALYSIS
------------------
*CaO........ .65 13.50%
*MgO........ .20 3.00%
*K2O........ .01 .40%
*Na2O....... .13 3.04%
Fe2O3...... .01 .58%
TIO2....... .00 .10%
B2O3....... .76 19.54%
AL2O3...... .35 13.13%
SiO2....... 2.11 46.68%
P2O5....... .00 .04%
COST/KG 1.91
RATIO 6.05
EXPAN 296.91
WEIGHT 271.55
>>----------------------------Original message----------------------------
>>>Higby's 1-2-3 (cone 08)
>>>Gerstley Borate 30
>>>EPK 20
>>>Flint 10
>>>
>>>Hey! That doesn't add up to 100!
>
>>The Higby glaze is unbalanced at any cone - and - even though the B2O3
>>content is over 12% - making it difficult to predict expansion - it is way
>>low - Just so some testing with this to see if what ever you are making is
>>going to survive you glaze/clay combination.
>
>Ron,
>
>The Higby's 1-2-3 glaze is a Raku glaze and is made by volume and not by
>weight. When I run the numbers for it, I get something that looks like
>this...
>
>Recipe by volume:
> Flint 1
> EPK 2
> Gerstley borate 3
>
>
> Na2O 0.16 Al2O3 0.35 SiO2 2.11
> MgO 0.16 B2O3 0.75
> CaO 0.68
>
> Alumina:Silica ratio is 1.00 : 6.08
> Neutral:Acid ratio is 1.00 : 1.93
> Alkali:Neutral:Acid ratio is 1.00 : 1.09 : 2.11
>
>Expansion coefficient: 66.8 x 10e-7 per degree C
>Oxides causing abnormal expansion effects: B2O3
>
>I think you'll agree that the numbers look a little better this way. For a
>raku glaze it seems to have an adequate amount of silica. While I agree
>that mixing glazes by volume isn't nearly as precise as weighing them out,
>this one always works ok for me. I usually measure it out in cups.
>Considering the variable nature of the gerstley, I think that this seat of
>the pants/pants pockets approach to measuring is the way to go for this
>glaze.
>
>BTW I have learned a great deal of information about the chemistry involved
>in glazes from your postings as well as the postings of Tony, Craig and
>Tom. I am sure that there are countless others on this list benefiting
>from the wealth of information you all share so freely. Thanks!
>
>
>John Post
>jp6mchp@moa.net
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
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
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