mel jacobson on fri 6 dec 02
it has been published many times.
it is a good throwing, basic white clay.
25 percent of each:
epk or grolleg
silica
feldspar
ball clay
i add a bit of sand and fine grog.
and, for me....about 15 percent stoneware clay to round it off.
(also lake superior iron sand to speckle it. ) pug three times.
see, not a purist. gray porcelain.
mel
it makes a great slip....1 cup each of the basics and water. blender
for 10 minutes.
From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
John Rodgers on sat 2 jul 11
In digging through a bunch of old notes and papers, I ran across this
throwing clay body recipe. Just wondering if anyone uses it and could
tell me something about it, particularly the components.
Alfred Porcelain (Cone 10)
Kaolin (Grolleg) 55
Feldspar (Kona F4) 20
Pyrophillite 13
Silica 12
Total of 100 parts
Add Macaloid 2%
Notes say - Expensive, but well worth it.
Questions:
1) Can EPK be subbed for the Grolleg
2) What if any substitution can be made for the Kona F4
3) What is Pyrophillite? Is it still readily available? Is there a
substitute.
4) What adjustments might be made to lower the temp range to a Cone 6
without spoiling the broth, so to speak.
Thanks,
John
--
John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com
David Finkelnburg on sat 2 jul 11
John,
In general, to adjust any C10 body to C6, leave the clay alone and
replace some of the silica with an equal percent by weight of feldspar.
You can replace the Grolleg with any kaolin, including EPK. The body
will not be quite as white!
Pyrophyllite is an aluminum silicate mineral added to reduce fired body
expansion. Kyanite is similar. Chemically kaolin is similar but the working
characteristics of the body will not be the same.
Sub any soda spar available for the Kona F4 but testing for desired
level of vitrification will be required.
As Ron Roy has pointed out many times on the list, any body which uses =
a
single clay is risky. Any change in that clay will alter the body. It would
be more prudent, if one is going to the trouble to develop a new body for
their work, to use a blend of at least three clays.
Good potting and happy Fourth of July (to those who celebrate it)!
Dave Finkelnburg
http://www.mattanddavesclays.com
-----------------------------
On Sat, 2 Jul 2011 06:00:31 -0500, John Rodgers wrote:
In digging through a bunch of old notes and papers, I ran across this
throwing clay body recipe. Just wondering if anyone uses it and could
tell me something about it, particularly the components.
Alfred Porcelain (Cone 10)
Kaolin (Grolleg) 55
Feldspar (Kona F4) 20
Pyrophillite 13
Silica 12
Total of 100 parts
Add Macaloid 2%
Notes say - Expensive, but well worth it.
Questions:
1) Can EPK be subbed for the Grolleg
2) What if any substitution can be made for the Kona F4
3) What is Pyrophillite? Is it still readily available? Is there a
substitute.
4) What adjustments might be made to lower the temp range to a Cone 6
without spoiling the broth, so to speak.
ivor and olive lewis on sun 3 jul 11
Dear John Rodgers,
This sounds like a candidate for Lili's "Obsolete Recipe List"
Pyrophyllite is a mineral. It is an Hydrated Alumino Silicate, a rare
mineral found in some metamorphic rocks. It decomposes with loss of water
when heated but is relatively infusible. Though micaceous in habit it adds
nothing to the plastic nature of a clay body. Notes are difficult to find
but Glen Nelson tells us it can lower thermal expansion.
If I had none I would substitute Sillimanite or Kyanite on the presumption
that a refractory ingredient would reduce pyroplasticity in a cone 10
porcelain body. Constructing a recipe without it might drop its maturity
cone by four notches
It is a pity whoever extracted this recipe from Alfred College did not ask
its originator to provide explanatory notes when suggesting esoteric
materials.
Regards,
Ivor Lewis,
REDHILL,
South Australia
Eric Hansen on sun 3 jul 11
I know a potter who has used it in a flame ware body since before the
1970's - in Kansas City. The material is still available there, I just
checked.
- h -
On Sun, Jul 3, 2011 at 3:23 AM, ivor and olive lewis
wrote:
> Dear John Rodgers,
>
>
>
> This sounds like =3DA0a candidate for Lili's "Obsolete Recipe List"
>
> Pyrophyllite is a mineral. It is an Hydrated Alumino Silicate, a rare
> mineral found in some metamorphic rocks. It decomposes with loss of water
> when heated but is relatively infusible. Though micaceous in habit it add=
=3D
s
> nothing to the plastic nature of a clay body. Notes are difficult to find
> but Glen Nelson tells us it can lower thermal expansion.
>
> If I had none I would substitute Sillimanite or Kyanite on the presumptio=
=3D
n
> that a refractory ingredient would reduce pyroplasticity in a cone 10
> porcelain body. Constructing a recipe without it might drop its maturity
> cone by four notches
>
> It is a pity whoever extracted this recipe from Alfred College did not as=
=3D
k
> its originator to provide explanatory notes when suggesting esoteric
> materials.
>
> Regards,
>
> Ivor Lewis,
> REDHILL,
> South Australia
>
--=3D20
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
C. Tullis on sun 3 jul 11
This recipe came to me via Victor Babu at a workshop
some slight differences, I subbed macaloid for the bentonite. Pyrophylit=
=3D
e is=3D20
sold as Pyrax. I made another variation of this subbing 1/3rd of the gr=
=3D
olleg=3D20
with #6 Tile + a pinch of shredded nylon fiber and vinegar to taste.
Recipe Name: Babu's Porcelain
Cone: 8 - 10 Color: White
Firing: Ox. or Red. Surface: =3DA0
Amount Ingredient
55 Kaolin--Grolleg
20 Feldspar--Custer
13 Flint
12 Pyrophyllite
100 Total
Additives
2 bentonite
Unity Oxide
.19 Na2O
.571 K2O
.077 MgO
.162 CaO
1.000 Total
4.501 Al2O3
.045 Fe2O3
17.989 SiO2
.004 TiO2
4 Ratio
5.6 Exp
Comments:=3D20=3D20
-----------------------------------
Calculations by GlazeMaster=3D99
www.masteringglazes.com
------------------------------------
John Britt on sun 3 jul 11
Pyrophyllite is a.k.a. as Pyrax HS and is still available. Also check Py=
=3D
rotrol 2253 .
johnbrittpottery.com
Paul Herman on sun 3 jul 11
Clyde and All,
I have used this formula for porcelain with the Pyrax (pyrophylite.)
Ivor, we can still buy this material over here. You don't have it down
under?
The clay body threw well enough, but didn't even show the slightest
hint of translucency. Kind of chalky and white compared to the other
porcelains I am familiar with. Because of the lack of translucence, I
probably won't be using it much more. I wonder if the Pyrax is the
reason. Any one have an opinion?
best,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Jul 3, 2011, at 6:29 AM, C. Tullis wrote:
> This recipe came to me via Victor Babu at a workshop
> some slight differences, I subbed macaloid for the bentonite.
> Pyrophylite is
> sold as Pyrax. I made another variation of this subbing 1/3rd of
> the grolleg
> with #6 Tile + a pinch of shredded nylon fiber and vinegar to taste.
>
> Recipe Name: Babu's Porcelain
>
> Cone: 8 - 10 Color: White
> Firing: Ox. or Red. Surface:
>
> Amount Ingredient
> 55 Kaolin--Grolleg
> 20 Feldspar--Custer
> 13 Flint
> 12 Pyrophyllite
>
> 100 Total
>
> Additives
> 2 bentonite
>
ivor and olive lewis on mon 4 jul 11
Dear Paul Herman,
I have Pyrophyllite in stock but have never used it.
Oz is rich in minerals .
All the best,
Ivor.
C. Tullis on mon 4 jul 11
I used this body quite a bit before passing into the parallel parallel un=
=3D
iverse of=3D20
Terra Cotta bird feeders and Majolica. I think the Pyrophilite does decre=
=3D
ase the=3D20
translucency a little and it also decreases it's fired expansion. Glazes =
=3D
rarely=3D20
crazed and pieces performed well as baking dishes except for in the case =
=3D
of=3D20
my mom's insistance for using them under a full-on broiler.
I ran a couple of the "standard porcelain bodies up the GM flagpole and g=
=3D
ot=3D20
this....
notice the domestic equal parts formula has the lowest coefficient of=3D20
expansion
Mile Hi Ceramics in Denver makes a "Babu" porcelain that is close=3D20=3D20
Recipe Name: Standard European Porcelain
Cone: 10 Color: white
Firing: Ox. or Red. Surface:=3D20=3D20
Amount Ingredient
55 Kaolin--Grolleg
25 Feldspar--Custer
25 Flint
105 Total
Additives
2 Macaloid
Unity Oxide
.186 Na2O
.533 K2O
.058 MgO
.223 CaO
1.000 Total
3.432 Al2O3
.029 Fe2O3
15.881 SiO2
.003 TiO2
4.6 Ratio
5.7 Exp
Comments:=3D20=3D20
-----------------------------------
Calculations by GlazeMaster=3D99
www.masteringglazes.com
------------------------------------
Recipe Name: Babu's Porcelain
Cone: 8 - 10 Color: White
Firing: Ox. or Red. Surface: =3DA0
Amount Ingredient
55 Kaolin--Grolleg
20 Feldspar--Custer
13 Flint
12 Pyrophyllite
100 Total
Additives
2 Macaloid
Unity Oxide
.19 Na2O
.571 K2O
.077 MgO
.162 CaO
1.000 Total
4.501 Al2O3
.045 Fe2O3
17.989 SiO2
.004 TiO2
4 Ratio
5.6 Exp
Comments:=3D20=3D20
-----------------------------------
Calculations by GlazeMaster=3D99
www.masteringglazes.com
------------------------------------
Recipe Name: Domestic Porcelain
Cone: 10 Color: white
Firing: Ox. or Red. Surface:=3D20=3D20
Amount Ingredient
25 Kaolin--EPK
25 Ball Clay--Old Mine #4
25 Feldspar--Custer
25 Flint
100 Total
Additives
1.5 Macaloid
Unity Oxide
.212 Na2O
.477 K2O
.05 MgO
.26 CaO
1.000 Total
3.167 Al2O3
.048 Fe2O3
17.224 SiO2
.073 TiO2
.003 P2O5
5.4 Ratio
5.6 Exp
Comments:=3D20=3D20
-----------------------------------
Calculations by GlazeMaster=3D99
www.masteringglazes.com
------------------------------------
Ron Roy on wed 6 jul 11
I've been talking to Clyde and he wanted me to post this so all can =3D20
understand.
When calculating expansion - it only works for glossy glazes - not =3D20
matte glazes or clays.
I think - in the case of matte glazes - the crystals act in a way that =3D2=
0
cannot be predicted - not only in content but also amount.
The same thing is true in a clay body - and also any free quartz or =3D20
cristobalite has a profound effect on expansion.
This does not mean that calculation cannot be used in clay body work - =3D2=
0
just that the expansion part cannot be used.
RR
Quoting "C. Tullis" :
> I used this body quite a bit before passing into the parallel =3D20
> parallel universe of
> Terra Cotta bird feeders and Majolica. I think the Pyrophilite does =3D20
> decrease the
> translucency a little and it also decreases it's fired expansion. =3D20
> Glazes rarely
> crazed and pieces performed well as baking dishes except for in the case =
o=3D
f
> my mom's insistance for using them under a full-on broiler.
>
> I ran a couple of the "standard porcelain bodies up the GM flagpole and g=
o=3D
t
> this....
>
> notice the domestic equal parts formula has the lowest coefficient of
> expansion
>
> Mile Hi Ceramics in Denver makes a "Babu" porcelain that is close
>
> Recipe Name: Standard European Porcelain
>
> Cone: 10 Color: white
> Firing: Ox. or Red. Surface:
>
> Amount Ingredient
> 55 Kaolin--Grolleg
> 25 Feldspar--Custer
> 25 Flint
>
> 105 Total
>
> Additives
> 2 Macaloid
>
> Unity Oxide
> .186 Na2O
> .533 K2O
> .058 MgO
> .223 CaO
> 1.000 Total
>
> 3.432 Al2O3
> .029 Fe2O3
>
> 15.881 SiO2
> .003 TiO2
>
> 4.6 Ratio
> 5.7 Exp
>
> Comments:
> -----------------------------------
> Calculations by GlazeMaster=3D99
> www.masteringglazes.com
> ------------------------------------
>
>
> Recipe Name: Babu's Porcelain
>
> Cone: 8 - 10 Color: White
> Firing: Ox. or Red. Surface:
>
> Amount Ingredient
> 55 Kaolin--Grolleg
> 20 Feldspar--Custer
> 13 Flint
> 12 Pyrophyllite
>
> 100 Total
>
> Additives
> 2 Macaloid
>
> Unity Oxide
> .19 Na2O
> .571 K2O
> .077 MgO
> .162 CaO
> 1.000 Total
>
> 4.501 Al2O3
> .045 Fe2O3
>
> 17.989 SiO2
> .004 TiO2
>
> 4 Ratio
> 5.6 Exp
>
> Comments:
> -----------------------------------
> Calculations by GlazeMaster=3D99
> www.masteringglazes.com
> ------------------------------------
>
>
> Recipe Name: Domestic Porcelain
>
> Cone: 10 Color: white
> Firing: Ox. or Red. Surface:
>
> Amount Ingredient
> 25 Kaolin--EPK
> 25 Ball Clay--Old Mine #4
> 25 Feldspar--Custer
> 25 Flint
>
> 100 Total
>
> Additives
> 1.5 Macaloid
>
> Unity Oxide
> .212 Na2O
> .477 K2O
> .05 MgO
> .26 CaO
> 1.000 Total
>
> 3.167 Al2O3
> .048 Fe2O3
>
> 17.224 SiO2
> .073 TiO2
> .003 P2O5
>
> 5.4 Ratio
> 5.6 Exp
>
> Comments:
> -----------------------------------
> Calculations by GlazeMaster=3D99
> www.masteringglazes.com
> ------------------------------------
>
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