Thonas C. Curran on sat 21 nov 98
Have never come across Gibby's Wild Rose Tenmoku or its variations. Can
someone offer up a recipe for same? Sounds like an interesting glaze to
play around with. Am also interested in a raku glaze which will fire a
copper red with post firing reduction. Will share my experiments once
I've had time to do more...
Carolyn Nygren Curran aka cnc
John Post on sun 22 nov 98
At 10:00 AM 11/21/98 EST, you wrote:
>----------------------------Original message----------------------------
>Have never come across Gibby's Wild Rose Tenmoku or its variations. Can
>someone offer up a recipe for same?...
Hi Carolyn,
Here is the wild rose you requested....
***Just so Ron Roy doesn't have to say it, this glaze has too much lithium
and is most likely not food safe. It is also low in silica which adds to
its problems in regards to food safety. In my experience I have found that
this glaze frequently shivers off of the rims of pots. If you drop the
lithium down to 3.0 moles or less and increase the amount of silica in the
glaze the shivering problems disappear. I have also found that a
controlled cooling of this glaze helps it to develop nice small
sparkles/crystals.
My firing schedule with a glaze similar to this one is...
climb at 200 degrees an hour up to 700 degrees F
climb at 300 degrees an hour up to 2219 degrees F
drop at 250 degrees an hour down to 1800 degrees F
drop at 75 degrees an hour down to 1292 degrees F
let the kiln cool naturally from here.
The slow cool down at the end really helps the iron reds to develop as well
as the small sparkly crystals in the glaze. Try this glaze with a
controlled cool down and then without and you will notice the difference.
I started playin with controlled cool downs after talking with Janet Walker
about them. It has made a big difference in the appearance of many of my
matt glazes.
Good luck with it...
+++++++++++++++++++++++++++++++++++++
+++ Gibby's Wild Rose Tenmoku +++
+++++++++++++++++++++++++++++++++++++
Date: 01/08/98
Lithium carbonate 38 9.5% Hazard!
Bone ash 38 9.5% Hazard!
Nepheline syenite 222.64 55.7%
EPK 63.36 15.8% Hazard!
Red iron oxide 38 9.5%
-------- ------
400 100 %
Cost: $ 2.19 per kg glaze
$ 0.88 per 400 g batch
===========================
Chemical Analysis
===========================
Na2O 0.27 Al2O3 0.54 SiO2 1.96
K2O 0.08 P2O5 0.08
MgO 0.00 Fe2O3 0.17
CaO 0.28
Li2O 0.37
Alumina:Silica ratio is 1.00 : 3.63
Neutral:Acid ratio is 1.00 : 4.10
Alkali:Neutral:Acid ratio is 1.00 : 0.54 : 2.22
Expansion coefficient: 91.3 x 10e-7 per degree C
Oxides causing abnormal expansion effects: Li2O
John Post
Sterling Heights, Michigan USA
rp1mrvl@moa.net
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