JUNE PERRY
SHAMBHALA POTTERY
C10R GLAZES
GROUP 4
****NOTE: Many raw materials used in ceramics are toxic and one should thoroughly acquaint ones self with these materials and their proper handling and usage. Some glazes, such as those with high barium and high copper content, for example, or other high concentrations of coloring oxides, should not be used for items intended for food, or even anything that someone might inadvertently be able to use to store or serve food. Many glazes may be lacking in their base formulation, the minimum amounts of silica and/or alumina to properly hold the oxides in solution, making for a glaze that may be potentially unstable and potentially harmful when used to serve or store food or liquids.
I highly recommend that functional potters particularly, have their glazes tested for leaching of any potentially toxic materials. The lab at Alfred University does now for a very reasonable fee (about $15 per test). You can find information on this in the Clayart archives (see my Links page for a link), or write or call Alfred University directly.
Most of the clay bodies in the tests on this page were either from Laguna Clay in southern California, or Georgies in Portland.
RECIPES
Top row far left tile is # #416 on either Rods Body or Amador. This is a high alumina, very rich, buttery glaze that is showing a tiny bit of crazing on this test. You can't see it with the naked eye, but it does show up on an enlarged photo. If you're getting any crazing try version 2: lower whiting to 6, up Magnesium Carbonate to 4 and add 2 grams of silica. I think that will solve the problem. I would up the kaolin to 11 and add 2 silica if you want to maintain the same alumina/silica ratio. Without the extra 2 grams of silica, it's a hair lower than minimum as per Insight's 5.0 software. Also, if you just lower the whiting and up the magnesium carbonate, and add the silica (leaving the kaolin the same), it will still have the buttery surface but will lower expansion to a level that may solve the little bit of crazing.
80 Kona F4 Sodaspar
8 Whiting
8 Kaolin
2 Bone Ash
2 Magnesium Carbonate
Top row second tile from the left is #2649Revised June Perry's Chun base Color B. This did not reduce and if you look very closely to the tile, you'll see one or two tiny red specks where the copper did reduce. I wanted a copper red that would have his pretty copper green if it didn't reduce. I got my wish! LOL If anyone tries this with their other copper reds, I'd love to hear of your results. This recipe is .07 higher than the .7 maximum limit for Calcium but the rest of the materials are within C10 limits.
29.04 Custer Feldspar
7.86 Whiting
6.07 Gerstley Borate
6.12 Dolomite
3.02 Barium Carbonate
1.16 Zinc Oxide
12.93 Grolleg
33.80 Silica
ADD: Tin Oxide 2%
Color B, ADD: 1% Copper Carbonate
Top row, third tile from the left is #2324 June Perry's Calcium Matt D Color on a porcelain tile. This glaze has a really lovely, matt surface. The color is a very pale celery green on this porcelain tile and would go darker on an iron bearing stoneware or over a low iron (1-2%) engobe.
35.48 Nepheline Syenite
13.79 Dolomite
8.49 Whiting
15.55 EPK
1.77 Ball Clay
24.92 Silica
Color D, Substitute Red Horse or other red clay like Red Art for the EPK. Add 2% Bentonite
Top row, far right is #54 Color A on an iron bearing stoneware. This color is not showing true in this scan. It's a very rich, very dark green. I have used this very reliable celadon, buttery base for years with 1-3% red iron for various depths of green. The C version will give a light, but rich celadon in proper reduction, particularly if you fire alternate periods of neutral or light reduction and then heavier reduction. The expansion on this in my 5.0 version of Insight is 6.62. SiO2/Al2O3 ratio is 8.44. The Calcium is higher than the C10 limit recommendation but all other materials are within limits.
27.32 Custer Feldspar
19.66 Whiting
20.00 EPK
33.02 Silica
Color A, ADD: 3.5% Red Iron Oxide
Color B, ADD: 2.5% Red Iron Oxde
Color C. ADD: 1% Red Iron Oxide
Second row from the top, far left is #999 C9-10 on Los Altos. It is olive green on the top portion where it was double dipped and a rich dark red matt on the bottom with a single dip. This glaze is better at full cone 9 or cone 10 starting. It can tend to run at flat cone 10. I got this glaze from Tom Reece, and he has gotten it from Wayne Cardinalli, and that's about as far as I could trail it.
49.3 Custer Feldspar
19.9 Whiting
3.7 Talc
3.7 Bone Ash
23.4 EPK
ADD: 4% Red Iron Oxide
**I did another version with 5.5 Red Iron as well. I think it was a bit redder, but I've since lost of misplaced the test tile.
#234 (***No picture on this one). This is another recipe from Tom Reece. It's a nice buttery glaze, rich orange/brown glaze which breaks nicely. This is very similar to a recipe known as Shaner Gold. This has a hair more iron and rutile. You might also try this without the colorants for a white. Or just add 1% rutile for a softer white. You can add tin or Zircopax if you need to opacify it, but I think it may be OK as it.
46.45 Custer Feldspar
22.09 EPK
18.82 Whiting
3.55 Talc
9.09 Bone Ash
ADD: Red Iron Oxide 4 %, Rutile 2
Second row from the top, second tile from the left is #2333 June Perry's Matt Kaki on a porcelain body. This is a very deep raspberry red, which is often called "Tessha". You can use this in soda/salt firings as well. In salt it came out a plum temmoku.
50.00 Custer Feldspar
18.0 Grolleg Kaolin
12.8 Silica
7.7 Whiting
11.5 Red Iron Oxide
Second row from the top, third tile from the left is #228 Color B. This is a lovely light, nickel green matt.
11.5 Colemanite
7.3 Dolomite
40.9 Kona F4 Soda Spar
7.2 Tennesses Ball Clay #1
14.0 Talc
19.1 Talc
Color B, ADD 3% Black Nickel Oxide.
Second row from the top, far right tile is #3108 Oatmeal on Windsor Porcelain. It's a pale gold with some darker gold inclusions. It would be darker rust/orange when applied on the thin side over an iron bearing body or over iron engobe.
49 Custer Feldspar
19 Dolomite
20 EPK
4 Whting
8 Zircopax
ADD: Tin Oxide 4%, Yellow Ochre 2%
Third row from the top, far left tile is # 3103 Shaner Oribe on an iron bearing clay body. The right side is considerably lighter because of the porcelain engobe underneath. This amount of copper may leach from this base, so have glaze tested before using on any functional work. You might want to try a version with 3.5-4% addition instead.
29.3 Custer Feldspar
24.0 Silica
21.2 Whiting
7.4 Talc
11.9 EPK
1.0 Bone Ash
1.0 Bentonite
5.2 Copper Carbonate
Third row from the top, second tile from the left is #719 C10-12 on an iron bearing stoneware. The right side of the tile has a white engobe underneath. Notice that there is not difference in the powder blue color where double dipped on top, but on the bottom, there is a difference in color and opacity between the raw body and the side with the slip. My tile only lists the .34 Cobalt carb, so I may not have added. the .20 chrome. You might want to try both versions. A close look at the tile makes me think that I did include the chrome oxide, but I just forgot to mark it.
47.40 Custer Feldspar
24.70 EPK
22.20 Dolomite
3.40 Whiting
1.50 Soda Ash
0.34 Cobalt Carbonate
0.20 Chrome Oxide
******The original called for .6 Cobalt Oxide instead of the 0.34 cobalt carbonate shown, which is why it doesn't add up to 100.
Third row from the top, third tile from the left is #2623 June Perry's Textured Semi-Matt Blue Color C. This glaze has a lot of textural interest, showing some brown where it's breaking over the incised lines. Other the Cao which is a hair high (.76 instead of .7) the rest of the materials are within C10 copper limits using Insight 5.0 software.
38.1 Custer Feldspar
19.0 Whiting
22.2 EPK
16.8 Silica
4.0 Titanium Dioxide
C color, ADD: Cobalt Carbonate 2%, Black Copper Oxide 1.5%
Third row from the top, far right tile is #1277 Ferguson Tomato Red on Santiam Clay body. The glaze is a hair lighter over the engobe on the right side of the tile. This test was very well reduced. If you want the color brighter on this saturated iron red, it would be best to fire them in a medium reduction with a little re-oxidation at top temperature. When they are heavily reduced they can get a lot of spider web, dark areas which you may or may not find desirable. When possible, I would put the iron red in the lower part of my kiln where I didn't get as good reduction.
54 Kona F4 Soda Spar
29 Silica
8 Kaolin (EPK or other)
8 Magnesium Carbonate
13 Bone Ash
8 Red Iron Oxide
Bottom row, far left tile is #2630 Apricot Shino on iron bearing stoneware. The right side has white engobe underneath the glaze. The back of this tile is smoother (nice waxy satin finish). This glaze looks like it could take more heat than cone 10. It has a good rich color with the traditional shino type pinholing. I'd love to have a pinched tea bowl with this glaze! Even without the good body reduction this glaze developed good color.
***PLEASE READ NOTES IN GLAZE BELOW FOR PROPER MIXING OF SODA ASH.
45 Nepheline Syenite
11 Custer Feldspar
15 Spodumene
4 Soda Ash
10 Monarch Kaolin (can use EPK or #6 Tile Clay,etc.)
5 OM#4 Ball Clay
Bottom row, second tile from the left is #2531 June Perry's Shino on Rods Body, I think. The right side has a porcelain slip under the glaze. This shino has a nice color even though I didn't get strong body reduction. It's a little smoother than the one to the left of it, but it still has some of the typical shino pinholing. There is no crazing on this body. *****PLEASE NOTE: Soda ash is one of the soluble glaze materials and if you make your glaze too thin and pour out the extra water, you'll be pouring out this valuable flux. Try to add only the amount of water needed and if you add to much, let the water evaporate to avoid losing the soda ash. There are other materials like Pearl Ash and Borax that are also soluble and should be treated the same way.
33.02 Kona F4 Soda Spar
25.75 Nepheline Syenite
14.51 Spodumene
20.61 OM#4 Ball Clay
3.90 Silica
2.21 Soda Ash.
For another variation you might try to substitute 1/2 of the ball clay with alumina hydrate. The higher alumina can often give a stronger red color to the shino. Also, if using it on a porcelain or white stoneware, you might try adding 5-6% Redart clay to get a red shino or try subbing the OM#4 with Redart in another test. Another test you might try to it sub 1/2 the Ball clay with Redart and the other 1/2 of the ball clay with a fine Alumina hydrate or alumina oxide.
Bottom row, third tile from the left is #1227 Ferguson Shino on Amador. This glaze shows just a few pinholes, but it is crazing where double dipped. The color on all three of these would be deeper if there were earlier and heavier reduction. I tested this on another clay in another firing and didn't get the crazing but I haven't yet been able to find the tile. Sometimes more heat eliminates crazing and sometimes less heat does the trick. You just have to test. Also, I find that in a higher iron body, I won't get as much crazing as I might with a lighter stoneware.
***SEE RECIPE #2531 ABOVE FOR INSTRUCTIONS ON USING SODA ASH.
14.6 Kona F4 Soda Spar
12.5 Spodumene
2.90 EPK
50.0 Nepheline Syenite
16.7 OM#4 Ball Clay
3.3 Soda Ash
Bottom row far right tile is #1203 Carbon Trap Shino on Amador. This is an example of extreme carbon trapping which can occur with strong, early reduction in some shino recipes. This recipe on porcelain can give a very intriguing blend of gold and grey in some firings. If using it on stoneware, you might want to try a version without the iron and then mix a tablespoon of each version to get a 1% version and test both on stoneware and porcelain.
66.6 Nepheline Syenite
16.6 Om#4 Ball Clay
10.0 Gerstley Borate
3.4 Talc
3.4 Whiting
ADD: 2% Red Iron Oxide
Email: ShambhalaPottery@frontier.com
