C/5/6/7 glazes:

Some mid-fire notes:

  1. Remember to clearly label and mark the firing cone on all of your glazes.
  2. Working with Cone 4-5-6 can be a wonderful experience.
  3. High iron clay bodies look wonderful in a cone 4 reduction.
  4. According to Whinney from the Tech Staff of Ceramics Monthly, the rule of thumb for conversion from C/10 to C/6 is to replace the feldspar with Nepheline Syenite and add 10% Colemanite (Gerstley Borate).
  5. Glazes containing Barium should be avoided for use with functional pottery.
  6.  

    Clear Glazes:

    CLEAR C/ 5-6

Gerstley Borate 48%
Flint 30%
Kaolin 22%

Patti's Crystal Clear ^5-7

Gerstley Borate 10.5%
Whiting 4.0%
Nepheline Syenite 15.0%
Kaolin 5.0%
Flint 15.5%

Cone 5-6 crackle glaze

Nepheline Syenite 70
Whiting 20
Six Tile clay 10

Clear C/6

Spodumene 50%
Gerstley Borate 25%
Flint 25%
Bentonite 1%

II CLEAR

Nepheline Syenite 47.3%
Gerstley Borate 27%
Flint 20.3%
China 5.4%

Glaze Name: Clear (Ian Begg)

Cone: 5 and 6

Surface: glossy, shiny

Firing: oxidation

1

Ferro Frit 3134 50 %
EPK 30 %
Silica 20 %
Totals: 100%

Glaze name: Clear (Huddleston)

Cone: 5-6

Color: transparent clear

Surface: glossy, shiny. Firing: oxidation

2

Flint 26%
Kona F-4 spar 32 %
Wollastonite 06 %
OM-4 Ball Clay 10 %
Frit P-54 16 %
Whiting 10 %
Totals: 100%

The Blues:

Float Blue (Cone 5 Ox)

Nepheline Syenite 47.3%
Gerstly Borate 27%
Silica 20.3%
EPK 5.4%
Cobalt Carbonate 1%
RIO 2%
Rutile* 4%

*Dark Rutile for dark blue.

Chappell s Clay and Glazes for the Potter pg 210

Cone 5-6 Ox

Nepheline syenite 47.3%
Gerstley Borate 27.0%
Silica 20.3%
EPK 5.4%
Red Iron Oxide 2.0%
Cobalt Oxide 1.0%
Rutile (milled) 4.0%
CMC* 1tsp

(May substitute with 2% Bentonite)

Cone 5 oxidation. Turquoise matte

Nepheline Syenite 60%
Strontium Carbonate 25%
Lithium Carbonate 2%
EPK 4%
Flint 9%
Copper Carbonate 4%
Bentonite 2 %

Ron Roy Cone 6-10 oxidation navy blue

Albany slip 80%
Gerstley Borate 20%
Cobalt carbonate 5%

Glaze name: Floating Blue-Chappell

Cone: 6

Recipe: Percent Batch
Nepheline Syenite 47.30% 2365
Gerstley borate 27.00% 1350
Flint (325m) 20.30% 1015
EPK 5.40% 270
Totals: 100.00 % 5000 gm
Cobalt oxide 1.00% 50
Red iron oxide 2.00% 100
Rutile 4.00% 200
CMC 0.15% 8

Unity Formula for Floating Blue-Chappell:

0.100 K2O 0.554 Al2O3 4.074 SiO2

0.420 Na2O 0.485 B2O3 7.4:1 Si:Al Ratio

0.476 CaO

0.004 MgO

Percentage Analysis:

61.61 % SiO2
14.23 % Al2O3
8.49 % B2O3
2.37 % K2O
6.55 % Na2O
6.72 % CaO
0.05 % MgO

Base Recipes with Colorant Variations

*Brutus Base*

Albany Slip 43 %
Wollastonite 38%
Whiting 15%
Lithium Carbonate 2%
Bone Ash 2%
For a Grey blue add

Cobalt

1%
For an orange

Add Red Iron Oxide

3%
And Rutile 1%

Pinnell Strontium Matt:

Lithium Carbonate 1.0%
Strontium Carbonate 20.0%
Nepheline Syenite 60.0%
Ball 10.0%
Flint 9.0%
Weathered Bronze  
Titanium Dioxide 5.0%
Copper Carbonate 5.0%
Weathered Blue  
Cobalt Carbonate .15%
Copper Carbonate 4.0%

Blacks:

Metallic Black cone 5-6

Gerstly Borate 11%
Whiting 5%
Potash   Feldspar 79%
E.P.K. 5%
Cobalt Carbonate 2%
Copper Carbonate 4%
Manganese Dioxide 4%

Metallic Glossy Black

Oxidation Cone 6 - 8

Feldspar 71.5%
Whiting 4.9%
Gerstley Borate 9.2%
Kaolin 4.4%
Copper Carbonate 3.0%
Manganese Dioxide 3.0%
Cobalt Carbonate 1.5%

Black ^6 oxidation [^7 in sitter] from Brian Kemp

Potash feldspar 42%
Silica 26%
Whiting 15%
Kaolin 15%
Zinc oxide 12%
Red iron oxide 8%
Cobalt oxide 1%

Gunmetal Gray Cone 6

Potash feldspar 39.15%
Flint (silica) 25.35%
E.P.K. 7.32%
Whiting 12.67%
Zinc Oxide 6.76%
Cobalt oxide 2.53%
Red iron oxide 3.66%
Manganese Dioxide 2.53 %

Matte Glazes:

White Satin Matt cone 4-7, oxidation

Potash Feldspar 52%
Whiting 19%
China clay/ EPK 14%
Zinc oxide 9%
Flint 6%

Smooth Matt C/6

Lepidolite 23%
Magnesium 2.3%
GB 5.4%
Wollastonite 20.8%
China Clay 14.7%
Flint 29.0%
Flourispar 4.8%

Satin Matt C/6

Potash feldspar 34.9%
Whiting 12.6%
Zinc 25.8%
China 4.1%
Flint 22.6%

Satin Matt

Potash 39.7%
Whiting 28.6%
Kaolin 13.8%
Flint 17.9%

Reds:

Cone 6. Tomato Red

Nepheline Syenite 55%
Silica 25%
Kaolin 10%
Dolomite 10%
Bone Ash 10%
Red Iron Oxide 10%
Bentonite 2%

"Floating Red"

Gerstley Borate 55
Talc 15
Flint 30
  100
Add: RIO 15

Purples:

Cone 6. Purple

Potash Feldspar 37%
Gerstley Borate 12%
Dolomite 6%
Talc 14%
Kaolin 5%
Silica 23%
Zinc Oxide 3%
Cobalt Carbonate 2%

Deep Purple, electric cone 6

Gerstley borate 8.4%
Nepheline Syenite 14%
(potash) feldspar 27%
Whiting 12%
Lithium carbonate 3.7%
Magnesium carbonate 1.7%
Flint 33%
Bentonite 2%
Tin oxide 5%
Cobalt carbonate 0.6%
Chrome oxide 0.17%

Egg Plant Semi gloss

Soda Feldspar 46%
Flint 15%
Talc 13%
Gerstly Borate 13%
Dolomite 9%
EPK 4.5%
Bentonite 1%
Cobalt Carb. 2%
Manganese Carb. 5%

Greens:

Cone 5 oxide Green matte

Nepheline Syenite 40 %
Wollastonite 25 %
Spodumene 12 %
EPK 12 %
Flint 11 %
Copper carbonate 4 %
Bentonite 2 %

"Faux Celadon" Cone 6 oxidation.

Soda Feldspar 50.00%
Wollastonite 20.00%
China Clay 10.00%
Silica 10.00%
Gerstley Borate 10.00%
Copper Carbonate 00.50%
Black Stain 00.20%

*K15 1*

Nepheline Syenite 40%
Dolomite 18%
Flint 18%
EPK 12%
Bone Ash 6%
Lithium Carbonate 2%
Zinc Oxide 4%
Copper Carbonate 2%

Cone 6 oxidation [^7 in sitter] from Clay Times

Nepheline Syenite 47.3%
Gerstley Borate 27.0%
Silica 20.3%
EPK 5.4%
  100.0%
red iron oxide 2.0%
cobalt oxide 1.0%
Rutile 4.0%
Bentonite 2.0%

Whites:

Pearly Cone 6

K200 Feldspar 26.3%
Flint 32.69%
Whiting 19.72%
EPK 12.05%
Zinc 6.57%
Magnesium Carbonate (light) 2.66%
  100%

Pike's Oatmeal

CUSTER FELDSPAR 2238.00 37.34%
COLEMANITE 762.00 12.71%
DOLOMITE 384.00 6.41%
TALC 816.00 13.61%
KAOLIN 270.00 4.50%
FLINT 1362.00 22.72%
ZINC OXIDE 162.00 2.70%
  5994.00 100%

White cone 5/6

Flint 29%
Calcium carbonate 13%
Frit 3134 19%
Kona F4 20%
Kaolin 19%
Superpax 12.5%

Glaze Name: V.C. Soft White Matt Cone: 5 - 6

Color: Semi Opaque White

Surface: Satin

Firing: Ox or Red

Tested: Untested Glaze Type: Na Li Mid-Road Shino Recipe:

Nepheline Syenite 54.00%
Barium Carbonate 9.00%
Gerstley Borate 11.00%
Lithium Carbonate 5.00%
Cryolite 5.00%
Zinc Oxide 2.00%
EPK 11.00%
Flint 3.00%
Totals: 100.00%
Tin Oxide 2.00%
Zircopax 5.00%

From Val Cushing.

Possible Health Hazards:

Barium Carbonate: HIGHLY Toxic-avoid ingestion. Do not use in glazes intended for use with food. Cryolite: Possibly Toxic - avoid breathing dust. Properly ventilate kilns - releases Fluorine when fired. Flint: free silica-wear a NIOSH approved dust mask when handling dry material

Estimated Thermal Expansion: x10-7

Analyses:

Unity Formula for V.C. Soft White Matt:

0.073 K2O 0.496 Al2O3 1.958 SiO2
0.370 Na2O 0.129 B2O3 0.409 F
0.137 CaO    
0.031 MgO    
0.190 Li2O    
0.129 BaO    
0.070 ZnO    

Percentage Analysis:

46.16 % SiO2
19.84 % Al2O3
3.52 % B2O3
2.70 % K2O
9.00 % Na2O
3.01 % CaO
0.49 % MgO
2.23 % Li2O
7.76 % BaO
2.24 % ZnO
3.05 % F

WAXY WHITE Cone 6

Wollastonite 37.2%
Silica 23.5%
EPK 14.9%
Nepheline Syenite. 14.5%
Gerstley Borate 9.9%

also, add 2% copper carbonate for Waxy Green.

Pinks:

PINK-TO-BURGUNDY (^6 OX)

Gerstley Borate 20.68% 1034
Nepheline Syenite 16.29% 814
EPK 11.34% 567
Whiting 19.52% 976
Flint 32.16 % 1608
Tin Oxide 5.00% 250
Green Chrome Oxide 0.15% .15%

Red/Pink Purple/Mauve ^6

Gerstley borate 21 %
Nepheline Syenite 16 %
Kaolin 11 %
Whiting 20 %
Silica 32 %
Tin 5 %
Chrome 0.15%

Pink Glaze

Ferro Frit 3134 32%
Custer feldspar 23%
Flint 22%
EPK l6%
Wollastonite 7%
Mason stain 6020 7%

Mirjana's Pink ^6

Strontium Carbonate 2.3 %(instead of barium)
Gerstley Borate 7.4%
Lithium Carbonate 2.3%
Magnesium Carbonate 8.6%
Whiting l6.4%
Nepheline Syenite 27.3%
Flint 35.7%
Tin oxide 3.5%
Rutile 3.0%

 

Cone 6 Pink

Gerstley Borate 21%
Nepheline Syenite 16%
Kaolin 11%
Whiting 20%
Silica 32%
Tin Oxide 5%
Chromium Oxide 0.15%

 

Browns:

Chocolate cone 4-5

Gerstley Borate 54.88%
Talc 14.63%
Flint 30.49%
RIO 21.95%

Carmel Corn

Gerstley Borate 51.0%
Silica 31.0%
EPK 16.0%
Custer 3.0%
Bentonite 1.0%
CMC 1 tsp.
Manganese Dioxide 10.0%
Rutile 5.0%

Strangely named glazes that I collected, but never tested.

Bright Glaze C/6

Volcanic Ash 62.3%
Frit 54 28.3%
China Clay 9.4%

GDR6 Cone 6 Oxidation

G200 or Custer Spar 32.00%
Whiting 14.00 %
Talc 6.0 %
Frit 3134 6.0 %
Ball clay (OM#4) 17.0 %
Silica 25.0 %
Total 100.0%