Glazes Theory And Practice Bryant Hudson

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Ceramic Glaze Theory and Practice

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Glazes Theory And Practice Bryant Hudson

  1. 1. Ceramic Glazes: Theory and Practice Bryant Hudson May 21, 2009
  2. 2. Goals • Better understand how glazes work • Become familiar with glaze compositions • Become familiar with glaze ingredients • Learn how to mix glazes • Learn how to compare glazes • Understand oxidation and reduction firing • Look at the Firehouse Studio glazes in detail
  3. 3. What is a Glaze ? • Glass that sticks to pottery • Glazes are mostly Silica • Pure Silica melts at 3100F • Add Sodium and Calcium to lower melting point (fluxes) • Add Aluminum to increase the viscosity
  4. 4. Periodic Table of the Elements Lots of elements to consider We want to work with common inexpensive materials Low hazard and non-volatile
  5. 5. Elements we use in the current set of studio glazes Of course everything is combined with Oxygen
  6. 6. Alkali Metals Strong fluxes active at all temperatures Lithium Carbonate (toxic) Na Feldspar – F4 feldspar Nepheline syenite Sodium Carbonate – Soda Ash (soluble, toxic) Potassium Feldspar – Custer Feldspar
  7. 7. Alkaline Earth Metals and Zinc Strong fluxes active at higher temperature Magnesium Calcium Carbonate – Dolomite Magnesium Silicate – Talc Magnesium Carbonate Calcium Carbonate – Whiting Strontium Carbonate Strontium Oxide Zinc Oxide
  8. 8. Non-metals and Aluminum These elements go into the basic glass network Gerstley Borate Borax Clays Feldspars Silicon dioxide – Quartz, Flint Clays Feldspars Calcium Phosphate – Bone Ash
  9. 9. Transition Metals - COLOR Chromium Oxide (toxic) Iron Chromate (toxic) Iron Oxide (Fe2O3 – red, Fe3O4 –black) Copper Carbonate (toxic) Cobalt Carbonate (toxic)
  10. 10. Opacifiers to decrease glaze transparency Titanium Dioxide – Rutile (>85% TiO2) Zirconium Silicate – Zircopax, Ultrox Tin Oxide
  11. 11. 17 Glazes from 18 Oxides derived from 27 different materials Al2O3 Bentonite 3D BLACK Black Iron Oxide TOMATO RED B2O3 Bone Ash CaO Borax BOB'S BLUE MATT Chrome Oxide CoO Cobalt Carbonate BRINGLE'S GREEN Copper Carbonate Cr2O3 BUTTERMILK Custer Feldspar CuO Dolomite DEPENDABLE RED FeO EPK Kaolin F-4 Feldspar GAIL'S WHITE K2O Ferro 3134 LAURA'S TURQUOISE Li2O Gerstley Borate Lithium Carbonate MYSTERY BLUE MgO Magnesium Carbonate Na2O Nepheline Syenite PIER BLACK OM-4 Ball Clay RACHEL'S BLUE P2O5 Red Iron Oxide SiO2 Rutile RUTILE Silica SnO2 Strontium Carbonate SEAFOAM Talc SrO SPECKLED LAVENDER Tenn #10 Ball Clay TiO2 Tin Oxide TENMOKU ZnO Ultrox (Zircopax) Whiting WOO BROWN TO BLUE ZrO2 Zinc Oxide YELLOW SALT
  12. 12. Clays Bentonite EPK (Kaolin) Primary source of OM-4 Ball Clay Aluminum Tennessee #10 Ball Clay Feldspars Custer Feldspar F-4 Feldspar Primary source of Li, Nepheline Syenite Na, and K, and also Spodumene provide Silica and Aluminum
  13. 13. Soda Ash Fluxes Lithium Carbonate Strontium Carbonate Strontium Oxide Sources of Lithium, Magnesium Carbonate Sodium, Magnesium, Dolomite Calcium and Strontium Talc Whiting
  14. 14. Borax Glass makers Ferro 3134 Sources of Boron, Gerstley Borate Silica and Silica Phosphorus Bone Ash Rutile Opacifiers Tin Oxide Sources of Titanium, Zinc Oxide Tin, Zinc and Zirconium Ultrox (Zircopax)
  15. 15. Chrome Oxide Colorants Cobalt Carbonate Copper Carbonate Red Iron Oxide Black Iron Oxide
  16. 16. Carbonates vs. Oxides or Silicates • Carbonates • Oxides or Silicates – Easier to make fine – Can be coarse and heavy powders and hard to disperse – Lower density and easier – No gas production to suspend in glaze – Less toxic because they – Produce large amounts are harder to absorb of CO2 – bubbles – Higher density means – Generally more toxic less material required Cobalt Carbonate vs. Cobalt Oxide Calcium Carbonate (whiting) vs. Wollastonite (CaSiO4)
  17. 17. Some of these compounds are toxic Lithium , Copper, Cobalt and Chromium are elements of concern Eat a spoonful of these and you will get sick or die We need small amounts in our diet to be healthy (1mg/d Li, 2mg/d Cu, 0.1 mg/d Co, 10mg/d Cr)
  18. 18. Chronic inhalation of dust • Regular inhalation of fine silica dust causes long term health problems • Fine silica powder is a mainstay of both clays and glazes • This is the number one health concern in the studio
  19. 19. Keep Dust Levels Low ! • Clean up drips and spills • Don’t dry sweep • Don’t dry sand inside the studio • If you have an apron, wash it regularly • If you have a towel, keep it damp, wash it • Transfer large bags of powder outside • …
  20. 20. Material Properties CAS # density solubility LD50 dust health g/cm3 g/L H2O mg/kg (rat) hazard NFPA Bentonite 1302-78-9 2.5 0 na serious 2 Black Iron Oxide 1317-61-9 5.2 0 20000 nuisance 0 Bone Ash 1306-06-5 3.1 0 10000 nuisance 0 Borax 1330-43-4 2.4 25 2400 moderate 1 Chrome Oxide 1308-38-9 5.2 0 10000 serious 2 Cobalt Carbonate 12602-23-2 4.1 0 640 serious 2 Copper Carbonate 12069-69-1 4.0 0 1350 nuisance 1 Custer Feldspar 68476-25-5 2.6 0 na serious 1 Dolomite 16389-88-1 2.8 0 6450 nuisance 1 EPK Kaolin 1332-58-7 2.7 0 na serious 2 F-4 Feldspar 68476-25-5 2.6 0 na serious 1 Ferro Frit 3134 65997-18-4 2.0 0 na moderate 1 Gerstley Borate 12046-09-2 2.4 5 >5000 nuisance 0 Lithium Carbonate 554-13-2 2.1 13 525 serious 2 Magnesium Carbonate 546-93-0 3.0 0 na nuisance 1
  21. 21. CAS # density solubility LD50 dust health g/cm3 g/L H2O mg/kg (rat) hazard NFPA Nepheline Syenite 37244-96-5 2.6 0 na nuisance 0 OM-4 Ball Clay 1332-58-7 2.5 0 na serious 2 Red Iron Oxide 1309-37-1 5.2 0 20000 nuisance 1 Rutile 1317-80-2 4.1 0 na nuisance 0 Silica 14808-60-7 2.7 0 na serious 2 Soda Ash (sodium carbonate) 497-19-8 2.5 300 4090 moderate 2 Strontium Carbonate 1633-05-2 3.5 0 >2000 nuisance 1 Talc 14807-96-6 2.6 0 na moderate 1 Tenn #10 Ball Clay 1332-58-7 2.5 0 na serious 2 Tin Oxide 1332-29-2 7.0 0 20000 serious 2 Ultrox (Zircopax) 14940-68-2 4.7 0 na serious 1 Whiting (calcium carbonate) 471-34-1 2.8 0 6450 nuisance 1 Wollastine 13983-17-0 2.8 0 na nuisance 0 Zinc Oxide 1314-13-2 5.6 0 na nuisance 0 CAS # - universal database number LD50 (rat) – 50% of rats will die if the consume this much material NFPA Health – 0 nontoxic, 1 slightly toxic, 2 moderately toxic, 3 highly toxic, 4 extremely toxic
  22. 22. Useful Information • http://digitalfire.com/4sight/material/
  23. 23. Melting Mixtures • Many of the glaze compounds melt at very high temperatures • Mixtures of these compounds melt at lower temperatures (Eutectic = easy to melt)
  24. 24. A simple real-world phase diagram
  25. 25. The first objects in the solar system were ceramic The small white inclusions are Ca-Al-silicates We can study their compositions and compare to known phase diagrams to infer the conditions under which they formed
  26. 26. On an atomic scale our ingredients are big • Melting begins at the contact points • Our “small” particles are still tens of thousands of atoms wide • This affects how the glaze melts
  27. 27. Kilns Electric Gas or Wood • Oxygen atmosphere • Combustion gas atmosphere • Precise temperature • Moderate temperature control control • Generally below 2250F • Routine operation to 2350F (cone 6) to increase filament life but can go to (cone 10) cone 10 • Capable of producing reduction atmosphere • Reduction difficult • Difficult to control
  28. 28. Combustion • CH4 + 2O2 CO2 + 2H2O (890 J/mole) – All the oxygen is consumed – Maximum heat production • CH4 + O2 CO + H2 + H2O (36 J/mole) – Not enough oxygen for complete combustion – Most of the fuel energy escapes – Large amount of carbon monoxide produced
  29. 29. There are many possibilities • CH4 +yO2 aCO2 + bCO +cH2 + dH2O + eC • Even molecules like CH3OH (methanol) • Details matter - burner geometry, kiln size • Gas kilns differ greatly
  30. 30. Why care about reduction ? • CO + 2CuO Cu2O + CO2 • Color changes in the transition metal colorants
  31. 31. Timing in the firing matters • Before the glaze melts, the glaze and clay are porous and interact with the kiln atmosphere • Once the glaze melts, the interaction with the kiln atmosphere takes place by diffusion – much slower
  32. 32. Timing in cooling matters • Once the burners are off, the atmosphere suddenly changes to being oxygen rich • As the glaze cools, some liquids or solids by come out of solution • Crystal formation is critical to copper red glazes • Crystal formation and phase separation give rise to many of the effects we like
  33. 33. Safety in firing the gas kiln • Carbon Monoxide – very toxic • You can hurt your eyes looking in the kiln • Volatile compounds – organic, sulfurous, metallic compounds Gases coming from the kiln, especially during reduction are dangerous. Stay away from the kiln during firing. Beware of the possibility of kiln exhaust entering the studio
  34. 34. Evaluating Glaze Compositions • Lots of different ingredients bring in some of the same oxides and it can be hard to compare glaze recipes • We need to be able to transform glaze recipes into lists of basic oxides • Instead of using weights, it is useful to calculate relative number of molecules
  35. 35. Calculating Molecular Fractions • Need to know the composition of each ingredient and what disappears during firing Custer Feldspar OM #4 Ball Clay Calcium Carbonate (whiting) CaO 0.30 CaO 0.30 K2O 10.28 K2O 1.00 CaO 56.10 Na2O 2.91 MgO 0.40 Al2O3 17.35 Na2O 0.30 LOI 43.90 SiO2 69.00 TiO2 1.20 Fe2O3 0.12 Al2O3 27.90 SiO2 55.20 LOI 0.04 Fe2O3 1.10 LOI 12.60 Values are weight % LOI = Loss On Ignition
  36. 36. Add pieces and normalize A recipe for a simple clear glaze 70% 10% 20% Oxide Mole wt. Custer F. OM4 BC Whiting weight moles mole % CaO 56.1 0.3 0.3 56.1 11.5 0.2043 14.8% K2O 94.2 10.3 1.0 7.3 0.0775 5.6% MgO 40.3 2.9 0.4 2.1 0.0515 3.7% Na2O 62.0 0.3 0.0 0.0005 0.0% TiO2 80.1 1.2 0.1 0.0015 0.1% Al2O3 101.9 17.4 27.9 14.9 0.1466 10.6% SiO2 60.0 69.0 55.2 53.8 0.8970 65.0% Fe2O3 159.7 0.1 1.1 0.2 0.0012 0.1%
  37. 37. Seger Unity Formula Seger Formula: Normalize the mole % values to the sum of the fluxes Oxide Mole % Seger Oxide Mole % Seger CaO 0.1480 0.61 SiO2 0.6500 2.678 K2O 0.0561 0.23 Al2O3 0.1062 0.438 MgO 0.0373 0.15 TiO2 0.0011 0.004 Na2O 0.0004 0.00 Fe2O3 0.0009 0.00 sum 0.2427 The Seger formula for a cone 6 cone has SiO2 = 6, a cone 7 cone has SiO2 = 7…
  38. 38. Mixing Glazes • Read and understand the recipe • Check to see if you have the ingredients • Equipment: – A scale to weigh materials – Containers to weigh materials and mix materials – Sieves to do the final mixing – Graduated cylinder and funnel to measure specific gravity – Protective equipment, dusk mask, gloves …
  39. 39. What I do to mix a glaze 1) Start with 0.5 liter of water per 1000g of dry material 2) Start with the hard to mix materials first 1) Bentonite, ball clay, EPK 3) Mix each ingredient as you add it 4) Add water to bring the specific gravity close to the correct value so the glaze isn’t too thick but still needs a little more water 5) Take notes (and keep them) of what you did 6) Take a break (30 min – a day) for material to hydrate – it will be easier to sieve and mix
  40. 40. What I do to mix a glaze 7) Spend several minutes with the drill mixer to thoroughly mix the glaze 8) Sieve the glaze a couple time (80 mesh, check recipe) 9) Check the specific gravity and add water to bring it to the correct value (about 1.6 – check recipe) 10) Check the thickness (viscosity). Test how it coats a piece of bisque pottery (want about 1mm) 11) If the glaze is thin, add epsom salt (MgSO4) (20g/10000g glaze) at a time until the glaze is thickened – no more than 100g/10000g total 12) Clean up the mess
  41. 41. Measuring Specific Gravity • Specific gravity is the measured density divided by the density of water • Weigh 100 ml of glaze and divide the weight by 100 • Measuring specific gravity is the best way to know how much water to add
  42. 42. Glaze Flocculation • Glazes are complex liquids – a suspension of fine particles • Clay particles have interesting surface properties and depending on what’s dissolved in the glaze, they will stick together • Dissolved Ca and Mg will cause glazes containing clay to flocculated • A flocculated glaze works well for dipping application • If a glaze doesn’t contain much clay, bentonite can be added (1-2%) • Some glazes will de-flocculate over time due to materials going into solution. Add small amounts of epsom salt (MgSO4) to re-flocculate the glaze
  43. 43. Glaze Flocculation • http://www.claytimes.com/articles/glazeadjusting.html • Adjusting Glazes for Application by Pete Pinnell, From the March/April and May/June 1998 issues of Clay Times
  44. 44. Measuring Glaze Thickness • Applying glaze at the proper thickness is important • Know the glaze and measure the thickness Use a razor blade to scrape a 90 degree scratch in the glaze. The width at the top is twice the thickness of the glaze
  45. 45. Summary of Glazes SiO2 Al2O3 B2O3 P2O3 TiO2 SnO2 ZrO2 Li2O K2O Na2O CaO MgO SrO ZnO Cr2O3 CoO CuO FeO 3D BLACK 0.75 0.07 0.01 0.03 0.08 0.004 0.05 TOMATO RED 0.65 0.08 0.02 0.02 0.03 0.08 0.05 0.06 BOB'S BLUE MATT 0.60 0.12 0.02 0.07 0.01 0.17 0.013 BRINGLE'S GREEN 0.51 0.09 0.01 0.04 0.02 0.06 0.13 0.10 0.033 0.01 BUTTERMILK 0.65 0.05 0.03 0.03 0.02 0.01 0.11 0.09 DEPENDABLE RED 0.65 0.07 0.02 0.005 0.02 0.04 0.12 0.02 0.04 0.004 GAIL'S WHITE 0.67 0.12 0.02 0.04 0.02 0.04 0.08 LAURA'S TURQUOISE 0.51 0.11 0.03 0.02 0.01 0.30 0.002 0.020 MYSTERY BLUE 0.71 0.07 0.03 0.03 0.01 0.14 0.006 PIER BLACK 0.50 0.12 0.01 0.04 0.02 0.14 0.08 0.02 0.042 0.03 RACHEL'S BLUE 0.69 0.07 0.04 0.03 0.03 0.13 0.007 RUTILE 0.63 0.08 0.07 0.02 0.01 0.14 0.05 SEAFOAM 0.70 0.07 0.03 0.03 0.01 0.14 0.022 SPECKLED LAVENDER 0.67 0.06 0.02 0.005 0.02 0.04 0.03 0.12 0.01 0.03 0.003 0.003 TENMOKU 0.68 0.07 0.03 0.01 0.12 0.08 WOO BROWN TO BLUE 0.70 0.07 0.03 0.03 0.01 0.12 0.03 YELLOW SALT 0.54 0.11 0.06 0.02 0.07 0.09 0.07 0.04 Values are mole %
  46. 46. Seger Mol% 3D Black 3D BLACK FH KNO CaO 0.239 0.457 4.42% 8.44% Silica 37.0 Al2O3 0.372 6.87% F-4 Feldspar 44.0 SiO2 4.043 74.65% Whiting 12.0 TiO2 0.001 0.02% EPK Kaolin 7.0 K2O 0.062 1.14% Na2O 0.178 3.28% Red Iron Oxide 6.4 CoO 0.034 0.43% Cobalt Carbonate 0.8 FeO 0.280 5.18%
  47. 47. Seger Mol% Tomato Red TOMATO RED FH KNO CaO 0.206 0.325 5.19% 8.21% MgO 0.215 5.43% F-4 Feldspar 48.22 Al2O3 0.311 7.85% Silica 25.89 P2O5 0.092 2.31% SiO2 2.56 64.59% EPK Kaolin 7.14 TiO2 0.001 0.02% Magnesium Carbonate 7.14 K2O 0.074 1.87% Bone Ash 11.61 Na2O 0.132 3.33% FeO 0.254 6.40% Black Iron Oxide 7.14
  48. 48. Seger Mol% Bob’s Blue Matt BOB'S BLUE MATT FH KNO CaO 0.316 0.021 9.01% 0.59% MgO 0.009 0.25% SrO 0.607 17.28% Nepheline Syenite 53 Al2O3 0.410 11.68% Tenn #10 Ball Clay 7 SiO2 2.097 59.74% Silica 8 TiO2 0.004 0.10% Strontium Carbonate 32 K2O 0.078 2.22% Na2O 0.239 6.79% Bentonite 2 CuO 0.045 1.29% Copper Carbonate 2 FeO 0.002 0.07%
  49. 49. Bringle’s Green KNO Seger 0.145 Mol% 5.7% CaO 0.147 5.8% Custer Feldspar 45.0 MgO 0.003 0.1% Whiting 7.0 ZnO 0.248 9.8% OM-4 Ball Clay 13.0 SrO 0.341 13.5% Al2O3 0.222 8.8% Strontium Carbonate 25.0 SiO2 1.286 50.7% Zinc Oxide 10.0 TiO2 0.029 1.2% Copper Carbonate 5.0 K2O 0.100 4.0% Rutile 1.0 Na2O 0.045 1.8% Red Iron Oxide 1.25 CuO 0.082 1.4%
  50. 50. Seger Mol% Buttermilk KNO CaO 0.15 0.47 3.5% 11.3% MgO 0.39 9.3% Gerstley Borate 9.63 Al2O3 0.20 4.9% Dolomite 6.23 B2O3 0.12 2.9% Whiting 8.25 SiO2 2.69 64.9% ZrO2 0.13 3.2% Custer Feldspar 26.88 TiO2 0.00 0.0% EPK Kaolin 6.23 K2O 0.09 2.1% Talc 12.38 Na2O 0.06 1.4% Silica 22.11 Zircopax 8.25
  51. 51. Seger Mol% Dependable Red KNO CaO 0.249 0.503 6.1% 12.4% Zinc Oxide 4.5 MgO 0.077 1.9% ZnO 0.153 3.8% Talc 3.5 Al2O3 0.302 7.5% Whiting 13.0 B2O3 0.100 2.5% Ferro 3134 10.8 SiO2 2.637 65.0% F4 Feldspar 45.5 TiO2 0.001 0.0% EPK Kaolin 5.2 K2O 0.067 1.7% Silica 16.0 Na2O 0.182 4.5% Bentonite 1.5 CuO 0.015 0.4% Tin Oxide 1.0 Copper Carbonate 0.7
  52. 52. KNO 0.335 6.4% Gail’s White CaO MgO 0.224 0.436 4.3% 8.3% Al2O3 0.627 12.0% Custer Feldspar 57.1 SiO2 3.496 66.9% EPK Kaolin 19.0 ZrO2 0.098 1.9% Dolomite 9.5 TiO2 0.003 0.1% K2O 0.230 4.4% Talc 9.5 Na2O 0.105 2.0% Zircopax 4.8
  53. 53. Seger Mol% Laura’s Turquoise KNO CaO 0.083 0.852 2.9% 29.7% Al2O3 0.327 11.4% SiO2 1.454 50.8% Whiting 38.1 TiO2 0.084 2.9% Custer Feldspar 23.8 K2O 0.057 2.0% EPK Kaolin 28.6 Na2O 0.026 0.9% Silica 9.5 CoO 0.005 0.2% Copper Carbonate 3.1 CuO 0.056 2.0% Cobalt Carbonate 0.25 Rutile 2.9
  54. 54. Seger Mol% Mystery Blue KNO CaO 0.228 0.738 4.3% 13.8% Al2O3 0.382 7.2% EPK Kaolin 10 SiO2 3.780 70.7% Whiting 20 TiO2 0.185 3.5% Silica 30 K2O 0.157 2.9% Custer Feldspar 40 Na2O 0.071 1.3% CuO 0.030 0.6% Rutile 4 Copper Carbonate 1
  55. 55. KNO 0.157 5.5% CaO 0.402 14.1% Pier Black MgO Al2O3 0.226 0.339 7.9% 11.9% B2O3 0.030 1.1% Custer Feldspar 42.7 SiO2 1.430 50.2% EPK Kaolin 23.6 TiO2 0.002 0.1% K2O 0.105 3.7% Dolomite 23.6 Na2O 0.052 1.8% Whiting 4.7 CoO 0.119 4.2% Borax 5.4 FeO 0.094 3.4% Cr2O3 0.048 1.7% Cobalt Carbonate 6.6 Black Iron Oxide 3.2 Chrome Oxide 3.4
  56. 56. Seger Mol% Rachel’s Blue KNO CaO 0.302 0.650 5.9% 12.7% MgO 0.006 0.1% Al2O3 0.369 7.2% Custer Feldspar 35 B2O3 0.200 3.9% OM-4 Ball Clay 17 SiO2 3.557 69.3% Whiting 12 TiO2 0.009 0.2% Silica 19 K2O 0.140 2.7% Na2O 0.162 3.2% Ferro 3134 17 CoO 0.037 0.7% Cobalt Carbonate 1.25
  57. 57. Seger Mol% Rutile KNO CaO 0.148 0.622 3.2% 13.5% MgO 0.226 4.9% Dolomite 15.8 Al2O3 0.370 8.0% Custer Feldspar 30.0 SiO2 2.906 63.2% Whiting 10.1 TiO2 0.321 7.0% EPK Kaolin 17.8 K2O 0.102 2.2% Silica 26.3 Na2O 0.046 1.0% Rutile 8.0
  58. 58. Seger Mol% Seafoam KNO CaO 0.210 0.678 4.2% 13.6% Al2O3 0.351 7.0% Custer Feldspar 40 SiO2 3.471 69.5% Silica 30 TiO2 0.170 3.4% Whiting 20 K2O 0.144 2.9% EPK Kaolin 10 Na2O 0.066 1.3% Rutile 4 CuO 0.109 2.2% Copper Carbonate 4
  59. 59. Seger Mol% Speckled Lavender KNO CaO 0.251 0.464 6.3% 11.6% MgO 0.002 0.1% ZnO 0.136 3.4% Zinc Oxide 4.0 Li2O 0.075 1.9% Lithium Carbonate 2.0 SrO 0.056 1.4% Whiting 14.0 Al2O3 0.239 6.0% Ferro 3134 7.0 B2O3 0.064 1.6% Silica 20.0 SiO2 2.685 67.0% K2O 0.150 3.8% Custer Feldspar 50.0 Na2O 0.101 2.5% Strontium Carbonate 3.0 CuO 0.013 0.3% Bentonite 1.0 SnO2 0.018 0.46% Tin Oxide 1.0 Copper Carbonate 0.6
  60. 60. Seger Mol% Tenmoku KNO 0.180 4.4% CaO 0.491 12.1% Al2O3 0.296 7.3% Custer Feldspar 43.4 SiO2 2.764 68.1% EPK Kaolin 10.3 TiO2 0.001 0.0% Whiting 18.3 K2O 0.124 3.0% Silica 28.0 Na2O 0.056 1.4% Red Iron Oxide 9.8 FeO 0.329 8.1%
  61. 61. Seger Mol% Woo Brown to Blue KNO CaO 0.223 0.603 4.5% 12.1% MgO 0.004 0.1% Whiting 18.0 Al2O3 0.348 7.0% Custer Feldspar 42.0 SiO2 3.465 69.5% TiO2 0.172 3.5% OM-4 Ball Clay 13.0 K2O 0.154 3.1% Silica 27.0 Na2O 0.069 1.4% Red Iron Oxide 4.0 FeO 0.170 3.4% Rutile 4.0
  62. 62. Seger Mol% Yellow Salt KNO CaO 0.322 0.318 9.3% 9.2% MgO 0.233 6.7% Al2O3 0.383 11.1% Nepheline Syenite 200 61.0 SiO2 1.875 54.1% Dolomite 20.0 ZrO2 0.206 5.9% OM-4 Ball Clay 4.0 TiO2 0.002 0.0% K2O 0.078 2.3% Zircopax 15.0 Na2O 0.244 7.0% Bentonite 1.0 FeO 0.127 3.7% Red Iron Oxide 4.0
  63. 63. SiO2 Al2O3 B2O3 ZrO2 K2O Na2O CaO MgO FeO GAIL'S WHITE 0.67 0.12 0.02 0.04 0.02 0.04 0.08 BUTTERMILK 0.65 0.05 0.03 0.03 0.02 0.01 0.11 0.09 YELLOW SALT 0.54 0.11 0.06 0.02 0.07 0.09 0.07 0.04
  64. 64. SiO2 Al2O3 B2O3 P2O3 TiO2 K2O Na2O CaO MgO Cr2O3 CoO FeO 3D BLACK 0.75 0.07 0.01 0.03 0.08 0.004 0.05 WOO BROWN TO BLUE 0.70 0.07 0.03 0.03 0.01 0.12 0.03 TENMOKU 0.68 0.07 0.03 0.01 0.12 0.08 TOMATO RED 0.65 0.08 0.02 0.02 0.03 0.08 0.05 0.06 PIER BLACK 0.50 0.12 0.01 0.04 0.02 0.14 0.08 0.02 0.042 0.03
  65. 65. SiO2 Al2O3 TiO2 K2O Na2O CaO MgO SrO ZnO CoO CuO FeO MYSTERY BLUE 0.71 0.07 0.03 0.03 0.01 0.14 0.006 0.006 SEAFOAM 0.70 0.07 0.03 0.03 0.01 0.14 0.022 WOO BROWN TO BLUE 0.70 0.07 0.03 0.03 0.01 0.12 0.03 RUTILE 0.63 0.08 0.07 0.02 0.01 0.14 0.05 LAURA'S TURQUOISE 0.51 0.11 0.03 0.02 0.01 0.30 0.002 0.020 BRINGLE'S GREEN 0.51 0.09 0.01 0.04 0.02 0.06 0.13 0.10 0.033 0.01
  66. 66. SiO2 Al2O3 B2O3 SnO2 Li2O K2O Na2O CaO MgO SrO ZnO CoO CuO DEPENDABLE RED 0.65 0.07 0.02 0.005 0.02 0.04 0.12 0.02 0.04 0.004 SPECKLED LAVENDER 0.67 0.06 0.02 0.005 0.02 0.04 0.03 0.12 0.01 0.03 0.003 0.003 A tiny bit of cobalt makes a big difference

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