Eleanora Eden on sat 7 jan 06
Hi David,
Here are some clay recipes I found yesterday on various websites (I
didn't keep track of what came from where). The first one is the
one I am using, given me by Jonathan K almost ten years ago.
I would like to add some fireclay to it to give it a bit of tooth...
You will see the 2nd one down is a porcelain ^4-6 recipe that is the
most likely one that I would try. What would you do to lower the
temp to ^1-3? What do you think of the amt of pyro in it?
Can you look it over and tell me what you think of it? I am
especially taken by the neph sy component being so large. I have
read up on neph sy in clay bodies and although good things are said
there is an article by Arbuckle in the archives (I'll include it
below) that says bad things about that.
It is cold out, and I've been sick, and I think Insight has taken ahold of me!
Any observations about any of the recipes would be very welcome.
Eleanora
Clay # 5 my throwing clay for C 1-3
Code Number: 97
15.00 Goldart
10.00 EP Kaolin
10.00 OM #4 Ball Clay
7.50 Custer Feldspar
3.75 Flint
3.75 Pyrax Pyrophyllite
0.25 Barium Carbonate
2.50 *this uses about 2.5 gal H20
0.05* BaO
0.14* CaO
0.12* MgO
0.51* K2O
0.18* Na2O
0.20 TiO2
4.75 Al2O3
18.96 SiO2
0.10 Fe2O3
Cost: 0.07
Calculated LOI: 8.68
Imposed LOI:
Si:Al: 3.99
SiB:Al: 3.99
Therm
C/4.5.6 White China Translucent
Code Number: 97
30.00 Nepheline Syenite
20.00 EP Kaolin
20.00 Grolleg Kaolin
20.00 Flint
5.00 Gerstley Borate
5.00 *kentucky ball clay
3.00 *veegum-T
0.32* CaO
0.07* MgO
0.17* K2O
0.44* Na2O
0.01 TiO2
1.87 Al2O3
0.16 B2O3
8.18 SiO2
0.02 Fe2O3
Cost:
Calculated LOI: 7.27
Imposed LOI:
Si:Al: 4.37
SiB:Al: 4.45
Thermal Expansion: 6.40
#6 Tile Wood/Salt body ^10-11
Code Number: 97
21.00 Tile #6 Kaolin
20.00 Custer Feldspar
18.00 EP Kaolin
18.00 OM #4 Ball Clay
14.00 Pyrax Pyrophyllite
5.00 Flint
4.00 *NEUMAN RED CLAY
0.14* CaO
0.12* MgO
0.53* K2O
0.21* Na2O
0.14 TiO2
4.82 Al2O3
18.52 SiO2
0.06 Fe2O3
Cost: 0.10
Calculated LOI: 8.47
Imposed LOI:
Si:Al: 3.84
SiB:Al: 3.84
Thermal Expansion: 5.62
Formula Weight:1701.76
C 6 porcelain clay slip
Code Number: 97
45.00 Nepheline Syenite
15.00 Silica
19.00 Ball Clay
19.00 Kaolin
2.00 Talc
0.07* CaO
0.14* MgO
0.19* K2O
0.60* Na2O
0.02 TiO2
1.86 Al2O3
8.78 SiO2
0.01 Fe2O3
Cost:
Calculated LOI: 4.89
Imposed LOI:
Si:Al: 4.72
SiB:Al: 4.72
Thermal Expansion: 6.63
Formula Weight: 786.12
goshen college stoneware ^8-11
Code Number: 97
13.00 Custer Feldspar
6.00 *200 mesh silica
18.00 OM #4 Ball Clay
21.00 Tile #6 Kaolin
14.00 Goldart
10.00 Hawthorne fireclay
5.00 *grog
0.10* CaO
0.21* MgO
0.50* K2O
0.18* Na2O
0.29 TiO2
5.50 Al2O3
17.02 SiO2
0.11 Fe2O3
Cost: 0.09
Calculated LOI: 8.41
Imposed LOI:
Si:Al: 3.10
SiB:Al: 3.10
Thermal Expansion: 5.77
>Formula Weight:1697.68
>Date: Thu, 4 Jun 1998 12:04:12 EDT
>
>Subject: Cone 6 clay
>
>
>I would be careful using neph sy as the body flux. It can be partially
>soluble and deflocculate the clay body. Make the clay particles line up
>parallel and slightly repel each other. Clay is hard to work with. Feels
>too wet, then dries on the outside, particles sit together, and inside
>water has trouble wicking out. Can cause cracking. We tried a recipe w/a
>lot of neph sy this spring, and it was just penance to work.
>
>
>Pete Pinnell gave us this advice:
>I don't know a distinct recipe, just some general guidelines. For a
>cone 6 light body you need about 20-25% flux with the rest being clay
>or a clay/filler combination. Neph sy can work but it will tend to
>deflocculate the clay unless it is counteracted with either epsom salts
>or calcium chloride. Soda spar or G-200 will also work, but are not as
>active so the clay will tend to be a bit more porous. You can also add
>just a small amount of talc and that will really tighten up the clay,
>but at a slightly heightened risk of cristobalite. The strongest
>spar/talc eutectic is at a ratio of five or six parts spar to one part
>talc.
>
>
>As for clay, it can be "to taste". It will stand up a lot better and
>crack a lot less if there is some fireclay, though very much will push
>the color to buff. Similarly, a little ball clay goes a long way to
>promote plasticity. Kaolin will give the whiteness, but you can't use
>it alone unless you also add some other filler such as flint or
pyrophyllite. If it were me i would start with the following:
Fireclay 20,
ball clay 20,
tile #6 kaolin 25
, flint 10
>, kona f-4 spar 25,
>bentonite 1.
> This will be pretty off-white (cream to buff), so if
>they want whiter they will have to accept the lower workability of a
>high kaolin body. They may want to add grog, in which case you could
>use something like Ione Grain if they want whiteness without the cost
>of Molochite. Kona can also cause deflocculation, so a little
>flocculant (one quarter percent) might be a good idea. Have them
>dissolve it first in hot water.
>
>
>This is just a starting point- they can adjust any of the components to
>fit their needs.
>
>
>--
>Linda Arbuckle
>Graduate Coordinator, Assoc. Prof.
Univ of FL
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