Kathy McDonald on thu 31 mar 05
-----Original Message-----
From: Kathy McDonald [mailto:potter@westman.wave.ca]
Sent: Tuesday, March 29, 2005 11:44 AM
To: Clayart
Subject: Iron Reds :Ohata Kaki (old recipies) Rhodes Red
I finally dug out my old glaze notebook for those
who wanted the recipie I have for Ohata Kaki.
I have not used this glaze for several years now
because I do not high fire in my electric kiln much anymore.
This is the basic recipie,perhaps others who regularly use
glaze clac software would like to check it out for composition variables
for the rest on the list.
Ohata Kaki (cone 10 ox or redux)
Bone ash ......10
Dolomite........7 (I have used talc but it tends to flake off bisque)
Whiting ........8
Kingman spar....47
EPK.............7
Flint...........21
RIO.............10
Best on white stoneware or porcelain.
This is the red I use all the time
breaks wonderfully to black at cone 10
redux on porcelain.
Rhodes Red Cone 10 redux
This is the recipie for a 10,000 g batch
Cornwall stone ...8500
Whiting...........1500
RIO...............1000
I do not know who to credit for these recipies
they have been ones I have had in my notebook for years.
The Rhodes one is particularly nice on porcelain and I've used it
for years,and the only problem I have encountered is the variability
in batches of Cornwall Stone that seem to affect the melt a bit.
Kathy
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Paulette Carr on fri 1 apr 05
On Mar 29, 2005, at 3:03 PM, Kathy McDonald wrote:
> This is the basic recipie,perhaps others who regularly use
> glaze clac software would like to check it out for composition
> variables
> for the rest on the list.
Thought that I would work this out for Rhodes Red, too. Thanks,
Kathy!!!
Rhodes Red [HF-red]
=========================================
Cornwall Stone.............. 85.00
Whiting..................... 15.00
+Iron Oxide Red.............. 10.00
=========
110.00
CaO 0.67* 10.94 12.64
K2O 0.13* 3.67 2.52
Na2O 0.18* 3.19 3.33
P2O5 0.01* 0.53 0.24
TiO2 0.00 0.10 0.08
Al2O3 0.51 14.98 9.52
SiO2 3.80 66.38 71.58
Fe2O3 0.00* 0.20 0.08
Si:Al: 7.52
SiB:Al: 7.52
Thermal Expansion: 7.37
Formula Weight: 344.26
Notes
Kathy McDonald: "This is the red I use all the time. Breaks
wonderfully to
black at cone 10red on procelain."
Standard RIO
My best,
Paulette Carr
Paulette Carr Studio
Member/Potters Council
St. Louis, MO
Paulette Carr on fri 1 apr 05
On Mar 29, 2005, at 3:03 PM, Kathy McDonald wrote:
> This is the basic recipie,perhaps others who regularly use
> glaze clac software would like to check it out for composition
> variables
> for the rest on the list.
Since Kathy was kind enough to hunt for and share her recipes, I have
done glaze calculations for Ohata Kaki. Because I use Custer Feldspar
rather than Kingman, I have made the substitution, and am also posting
these stats. I just used standard values from the material lists. If
you have the analyses for your materials you should redo this. Just a
note - I do find slight differences between the values obtained from
different glaze calc programs. For others working with the glaze, I
hope that this helps.
Ohata Kaki [HF-ox/red]
=========================================
Kingman Feldspar............ 47.00
Whiting..................... 8.00
Dolomite.................... 7.00
Bone Ash.................... 10.00
EP Kaolin................... 7.00
Flint....................... 21.00
+Iron Oxide Red.............. 10.00
=========
110.00
CaO 0.60* 14.12 16.48
MgO 0.11* 1.85 3.00
K2O 0.16* 6.21 4.31
Na2O 0.06* 1.45 1.53
P2O5 0.08* 4.60 2.12
TiO2 0.00 0.02 0.02
Al2O3 0.29 12.49 8.02
SiO2 2.35 59.22 64.51
Fe2O3 0.00 0.04 0.02
Si:Al: 8.05
SiB:Al: 8.05
Thermal Expansion: 7.62
Formula Weight: 238.57
Notes
from Kathy McDonald
"Years ago I used to use a glaze called Ohata Khaki that fired to a
great iron
red at cone 9 in an electric kiln. It was also nicer(redder) if you
refired it
to cone 06 after the cone 9 glaze firing."
Uses standard RIO.
Ohata Kaki [HF] (Custer Substitution)
=========================================
Custer Feldspar............. 53.10
Whiting..................... 8.60
Dolomite.................... 6.80
Bone Ash.................... 10.00
EP Kaolin................... 5.90
Flint....................... 15.60
+Iron Oxide Red.............. 10.00
=========
110.00
CaO 0.60* 14.32 16.70
MgO 0.11* 1.80 2.91
K2O 0.15* 6.03 4.19
Na2O 0.06* 1.69 1.78
P2O5 0.08* 4.59 2.11
TiO2 0.00 0.02 0.02
Al2O3 0.29 12.45 7.99
SiO2 2.32 59.07 64.29
Fe2O3 0.00 0.04 0.02
Si:Al: 8.05
SiB:Al: 8.05
Thermal Expansion: 7.67
Formula Weight: 236.18
My best,
Paulette Carr
Paulette Carr Studio
Member/Potters Council
St. Louis, MO
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