Richard Mahaffey on fri 26 nov 04
David,
The idea behind making cones with the same unity formula but different
recipes is to see the effect of different materials as I stated in my
original post.
The fact that it would be nearly impossible to make a cone that bent at
the exact time/temp as an Orton cone would illustrate
the concept that, even with the wonders of Glaze calc. programs,
changing the materials in a glaze changes the glaze.
To recap my original idea is below.
I felt that by making cones with different recipes you would be able to
learn about the difference that material choice makes more readily than
by glaze testing because of the bending factor. You begin to learn
something about the effect of various materials on the glaze melt.
By choosing cone 5 I thought we could position a pair of homemade cones
in the spy hole of our kiln (yes, it is indeed a large spy hole)
and see when the home made cones fell and compare that with the Orton
cone as a control then the cones would hopefully be out of the
way for the remainder of the firing.
Thanks for your post.
Rick Mahaffey - still looking for a unity (seger) formula for cone 4 or
cone 5.
Dave Finkelnburg on fri 26 nov 04
For those interested,
Rick Maheffy asked about cone recipes...the Seger formulas are available in the archives...any good glaze calc software will allow you to develop recipes from your materials to match the Seger formulas. Some things to keep in mind...
1. Orton makes great cones. Don't make your own to save money...if you must make cones do it to learn from the process.
2. Cones don't "melt" at a particular temperature in the sense we usually think of. Melting is controlled by thermodynamics and equilibrium phase diagrams indicate what is going on, but don't tell us all because our firings don't reach equilibrium.
3. Cones do sag (bend) due to high temperature creep. For repeatability in degree of vitrification of ware or glaze, a repeatable firing curve (especially top 200 degrees C) and peak firing temperature indication (good thermocouple) are things you must have.
4. Good ingredient mixing is the most critical factor in making the cones bend consistently (or preventing a clay body from sagging/warping in firing). Dry mix the ingredients, then slake them in a lot of water (density less than 1.5), ball mill the thin slurry if you can, mix the thin slurry with a good mixer like a high-speed glaze mixer, then allow the ingredients to settle, decant off clear water, dry to a working state for your forming process.
Good potting!
Dave Finkelnburg, who's reading Clayart inconsistently (today's the first time in a month) so if you want to reply to me, please, on your post to the list, copy me at dfwengr AT Yahoo.com. Thanks!
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Ivor and Olive Lewis on sun 28 nov 04
Dear Richard,
You say "still looking for a unity (Seger) formula for cone 4 or cone
5.
The abstract information you require is as follows.
Seger Cone 6a;
K2O - 0.3
CaO - 0.7
Al2O3 - 0.6
SiO2 - 6.0
Seger Cone 5a;
K2O - 0.3
CaO - 0.7
Al2O3 - 0.5
SiO2 - 5.0
Seger Cone 4a
K2O -0.3
CaO - 0.7
Al2O3 - 0.5
SiO2 - 4.0
An interesting starting point would be Whiting, Pearl Ash, Pure
Alumina and Pure Quartz using a medium to bind the powder that will
not dissolve the Pearl Ash.
Pearl Ash (K2CO3) will fuse or melt at about 900=BA C but may decompose
in the presence of free silica at a lower temperature. There is
potential for some interesting chemistry from mixtures formulated
using these raw compounds that might lead to some very useful frits.
If you do use this grouping of materials take due regard of the
following Eutectic Formulations;
K2O - 33%, SiO2 - 67% at 750=BA. C
K2O - 30%, CaO - 10%, SiO2 - 60% at 950=BA C
CaO - 24%, Al2O3 - 14%, SiO2 - 62% at 1170=BA C
Factual information from "Tables..." Kaye and Laby and "Handbook for
Australian Potters", De Boos, Harrison and Smith.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Ivor and Olive Lewis on mon 29 nov 04
Dear Richard,
I forgot to say that if you use a medium in which water soluble
ingredients do not dissolve you may use Potassium Nitrate or Potassium
Chloride as sources of Potassium in your formulations.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Hank Murrow on wed 5 jan 05
Sorry it took so long to reply to this thread......Hank
On Nov 25, 2004, at 12:04 PM, Gary Navarre wrote:
> The reference I recall is the potter made cones out of:
> 1. The clay body
> 2. Body + 5% wood ash
> 3. Body + 10% ash
> 4. Body + 15% ash
> 5. Maybe body + 20%
> This allowed him to determine boby vitrification.
> That plus draw tiles is what I think the old guys down south used.
> Hope
> that helps.
Dear Gary and Rick;
In David Green's book "Understanding Pottery Glazes", he shows a table
of cones. Here is a table from Cone 5 to Cone 13 in empirical formulae.
Cone # K2O CaO Al2O3 SiO2
5 .3 .7 .5 5.0
6 .3 .7 .6 6.0
7 .3 .7 .7 7.0
8 .3 .7 .8 8.0
9 .3 .7 .9 9.0
10 .3 .7 1.0 10.0
11 .3 .7 1.2 12.0
12 .3 .7 1.4 14.0
13 .3 .7 1.6 16.0
One may see how elegant the composition of cones is, and how rational
if one is conversant with empirical formulae.
Cheers, Hank in Eugene
www.murrow.biz/hank
John Britt on thu 6 jan 05
Edouard,
Yes, I have done this too. Nigel Wood talks about this in his great
book "Chinese Glazes".
I have even tried to "dissolve" Orton cone 4's, to use then as a glaze but
not much luck,
JOhn
John Britt on thu 6 jan 05
Hank,
Don't know if this happened to everyone but the cone formula column
headings on my post shifted to the left. K2O should remain 0.3 and Cao
should remain 0.7 while Alumina and Silica increase.
Thanks for the post. It is very beautiful - great step pattern on a graph
too,
John Britt
www.johnbrittpottery.com
>In David Green's book "Understanding Pottery Glazes", he shows a table
>of cones. Here is a table from Cone 5 to Cone 13 in empirical formulae.
>
>Cone # K2O CaO Al2O3 SiO2
> 5 .3 .7 .5 5.0
> 6 .3 .7 .6 6.0
> 7 .3 .7 .7 7.0
> 8 .3 .7 .8 8.0
> 9 .3 .7 .9 9.0
> 10 .3 .7 1.0 10.0
> 11 .3 .7 1.2 12.0
> 12 .3 .7 1.4 14.0
> 13 .3 .7 1.6 16.0
>
>One may see how elegant the composition of cones is, and how rational
>if one is conversant with empirical formulae.
>
>Cheers, Hank in Eugene
>www.murrow.biz/hank
>
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Edouard Bastarache Inc. on thu 6 jan 05
John,
I have made excellent glazes for C/9½ using the
chemical analysis of C/4 for the base.
Later,
"Ils sont fous ces quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
Ivor and Olive Lewis on fri 7 jan 05
Dear Hank Morrow,
This Mathematical Series is an illustration of the Genius of Herman
Seger. Realising that, with increasing temperature, the proportion of
the materials to which melting was attributed was decreasing, he
inverted proportionality giving us our universal Unity Formula. This
assists in simplifying calculations.
<< In David Green's book "Understanding Pottery Glazes", he shows a
table
> of cones. Here is a table from Cone 5 to Cone 13 in empirical
formulae.
>
> Cone # K2O CaO Al2O3 SiO2
> 5 .3 .7 .5 5.0
> 6 .3 .7 .6 6.0
> 7 .3 .7 .7 7.0
> 8 .3 .7 .8 8.0
> 9 .3 .7 .9 9.0
> 10 .3 .7 1.0 10.0
> 11 .3 .7 1.2 12.0
> 12 .3 .7 1.4 14.0
> 13 .3 .7 1.6 16.0
>
> One may see how elegant the composition of cones is, and how
rational
> if one is conversant with empirical formulae.
<< On Nov 25, 2004, at 12:04 PM, Gary Navarre wrote:
The reference I recall is the potter made cones out of:
> > 1. The clay body
> > 2. Body + 5% wood ash
> > 3. Body + 10% ash
> > 4. Body + 15% ash
> > 5. Maybe body + 20%
> > This allowed him to determine boby vitrification.
> > That plus draw tiles is what I think the old guys down south
used.
To what exent mixing wood ash with a raw clay body enables a person to
manufacture a practical clay body with an impervious structure is
uncertain. The alkali in an unwashed ash would cause foreseeable
problems. A well washed ash might, to some degree increase
refractoriness.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Ivor and Olive Lewis on fri 7 jan 05
Dear Edouard,
I would not have thought it possible to do this with pure oxides.
Or did you recalculate the unity formula and include a high potash
felspar as one of the ingredients.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
<< I have made excellent glazes for C/9=BD using the chemical analysis
of C/4 for the base.>>
Edouard Bastarache Inc. on fri 7 jan 05
Hello Ivor,
"Impossible n'est pas Français" said Napoleon Bonaparte.
As a starting point I used the Seger formula of C/4,
I have always admired the beautiful glossy white surface
of a melted C/4 everytime I have checked cone packs after
a C/9½ firing.
KNaO .3 Al2O3 .5 SiO2 4.0
CaO .7
I fed this analysis into a computer programme that told it was a "non-glaze"
I did not give it damn and tried it anyway, and it worked.
Here is the recipe after rounding up or down :
Custer spar 45
Whiting 17
EPK 14
Silica 24
I got a very nice dark celadon by adding 2% of a metallurgical waste
material
containing 85% ferric oxide. At 6% it gave a very dark green, at 9% waste
material + 9% Bone Ash it became brown/green glossy with specks probably
due to some impurities in the waste material. At 12 % waste material and
12 % Bone Ash it became brown with red specks.
Then I lowered the alumina portion to .400 and fed the new analysis and the
computer
programme told me it would be a very good base, so I made another series of
test
using increasing equal amounts of Cobalt Carbonate and Green Chromium Oxide
with good results.
The base recipe then became :
Custer spar 46
Whiting 18
EPK 7
Silica 28
In the next step I lowered the alumina portion even more at .300
and the results were again excellent, here is the new recipe :
Custer spar 48
Whiting 19
Silica 33
Later,
"Ils sont fous ces quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
Ivor and Olive Lewis on sat 8 jan 05
Dear Edouard,
I suspected that this was what you were speaking of. A great way to
go, strictly empirical.
It seems to be a watch word "Down Under" that if you do not know how
to go about making an original glaze pick a Seger Cone Formula four or
five cones below the maturing temperature of your clay and calculate a
recipe out using the materials at your disposal. Limiting in some a
ways but enlightening and always productive.
I think you have done a great job of work with this one and it should
be taken as a lesson to learn from by anyone who is wanting to make
the broad leap of faith towards self reliance and away from the recipe
books and the list provided by teachers.
I thank you for sharing your knowledge and experience.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Edouard Bastarache Inc. on sat 8 jan 05
Hello Ivor,
thank you for your very kind comments.
Later,
"Ils sont fous ces quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
Ivor and Olive Lewis on sun 9 jan 05
My dear Friend,
It is a pleasure to read about your trials and tribulations. I applaud
anyone who gets beyond the recipe books and explores new territory.
Those are wonderful glazes.
There are so many ways we can work without necessarily having high
tech machinery. Regrettably I could not use the residues from our
local smelter at Pt. Pirie. Pb with a vengeance. But there are other
queries nearby and Quarry dust can yield some useful fluxing
materials.Have you thought about approaching Deloro Stellite for the
floor sweepings form their foundry.
Keep up the good work.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
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