Recipes for Testing

[George Lewter]

If you find a recipe that intrigues you and want to know more about it, post it here to see if anyone else has any experience with it.  Please make a point of posting focused, high resolution photos of the fired glaze if you test the recipe.

[George Lewter]

This recipe was posted today on Ceramic Arts Daily for a matte black.  I plan to test it in my next firing, which may not be for a couple of weeks.  If you do a test, or already use this glaze, please reply with a picture.  This appears to be a calcium matte that will need a slow cool to develop it's matte surface. Firing cycle info should be included with the reply especially for the range from max temperature down to about 1600 deg. F.  I'm looking for an alternate to Pier Black that reportedly does not mature at cone 6.  Thanks, George L.

Black Matte Glaze
cone 6 oxidation
Whiting	17.9 %
Zinc Oxide	8.0
Potash Feldspar	49.2
EPK Kaolin	19.9
Silica	5.0
	100.0 %
Add: Red Iron Oxide	6.7 %
Cobalt Oxide	1.3 %

[Mary Jane]

Hi George - did you ever test that matte black glaze?  If so, what were the results?  Have your tried the strontium crystal magic at cone 6?  If so, do you have a long hold at high temperature?  I tried a test tile on a firing where the cone 6 cone was all the way down and it had not matured, but I have read elsewhere that it does mature.  Thx, MJ

[George Lewter]

I tested the Matte Black recipe last week and was quite pleased with the results.  Below, you see it on a bisqued tile of Laguna #80 brown stoneware and single fired on a Laguna B-mix5 raw tile.  Both tiles were fired to 2145 deg F, and held there for 1 hour. Rapid cooled to 1700 and held there for an hour, then shut down. On this shelf cone 6 ended up pointing to 3 o'clock. The slow cooling I thought was necessary for developing a matte surface did not seem to apply to this particular glaze.

 

This glaze fired similarly in appearance to Pier Black, but was mature at slightly less than cone 6.

I got a very interesting mottled effect when I layered this glaze over Strontium Crystal Magic (White). The Matte Black was thick over a thin layer of SCM .

The upper tile is over a highly textured surface, the lower is over a relatively smooth surface. Several pinholes did show up with this glaze combination.

I am firing the glaze now on a couple of pots to give the glaze an additional test.

[George Lewter]

Persimmon

There has been some interest in Steven Showalter's Persimmon Glaze.  We have a recipe by the same name in the Sankey Glaze Database here on the network and it definitely is public.

A: Persimmon
C: Cone 6
E: 46 borate,Gerstley
E: 29.4 silica
E: 22.5 kaolin,EPK
E: 9.8 iron oxide,red
E: 2 ash,soda
F: gloss
H: Alisa Clausen: a dark brown, reddish iron nuance. Needs to be applied evenly, dipped gave even results. Shiny, smooth, not too exciting by itself, but under Cream Gloss gave whitish to very blue opalescence with a honey ground, similar to combination of Plum and Cream Gloss.

 

Lana Wilson published one of her workshop handouts on the Web as a pdf file, and it contains virtually the same recipe with some interesting tips:

"Persimmon, cone 6 electric:

A cone 6 electric glaze that looks like reduction iron red. Fire to cone 6, then without adding any glaze simply re-fire to cone 06. The cone 06 firing changes the

dull brown produced by the cone 6 firing to a rich red. It is better where it is thick, but if it is too

thick it will run. THIS WORKS! Try Crocus Martis instead of iron.

Gerstley borate 47

Red iron oxide10

E.P.K. 23

Soda ash 0.2

Flint 30

" END of recipe

These should give you a starting place for persimmons.

[George Lewter]

I put the remaining Black Matte test glaze in my spray gun and used it on the inside and top rim of this planter, and was very pleased with the result. Satiny smooth and very uniform without being totally monotone.

[George Lewter]

Another recipe with a "persimmon" coloration, named Gibby's Wild Rose Khaki, is documented at John Hesselberth's Frogpond Pottery website and discussed on the clayart listserve. It is reported as possibly unsafe for Lithium leaching, and being out of the limits of a stable glaze.

I tested a very similar formula called Gibby's Wild Rose Tenmoku, and though it was spectacularly beautiful, it was very weak and shivered off the test tile, much to my dismay. It seem to have a frothy matrix instead of a solid glassy matrix.

John Post did a variation that I haven't looked into.

GIBBY'S WILD ROSE TENMOKU (J. POST VARIATION)
Cone 6 ox
Spodumene 27 %
Frit 3110 27.2%
EPK 18.3%
Bone ash 7.9%
Lithium carbonate 3.4%
Red iron oxide 7.9%
Flint 8.3%
(Modified from original by John Post)
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