Glass Phase Molecular Engineering
High-Fire Glaze Chemistry
Glazes are not liquid pigments; they are amorphous aluminosilicate glasses balanced in the Seger Unity Molecular Formula (UMF) system. Learn how fluxes, stabilizers, and glass formers coalesce to yield crystal-free, scratch-resistant, non-leaching surfaces.
Theoretical Foundation
The Seger Unity Molecular Formula (UMF)
STOICHIOMETRY
Column 1: RO / R₂O
Fluxing Oxides (Normalized to 1.00)
Alkali metals and alkaline earths that lower the melting point of silica.
- • K₂O / Na₂O: 0.20 – 0.30 (Vivid color, high expansion)
- • CaO: 0.50 – 0.70 (Durability, hardness)
- • MgO: 0.10 – 0.25 (Silk matte surface)
- • ZnO: 0.00 – 0.15 (Crystalline blooms)
Column 2: R₂O₃
Amphoteric Oxides
Viscosity stabilizers that prevent the molten glass from running off vertical vessel walls during peak heat-work soak.
- • Al₂O₃ (Alumina): 0.35 – 0.55 mol
- • Fe₂O₃ (Iron Oxide): 0.00 – 0.08 mol
- • B₂O₃ (Boron Oxide): In mid-fire glazes
Column 3: RO₂
Glass Formers
The structural backbone of the glass network. Excess silica leaves unmelted particles; deficient silica creates an acid-soluble, easily scratched glaze.
- • SiO₂ (Silica): 3.20 – 4.50 mol
- • TiO₂ (Titania): Opacity and phase phase-separation
- • ZrO₂ (Zirconia): White opacifier
Tested Lab Formulations
Field-Tested Cone 6 & Cone 10 Bases
RECIPE ARCHIVE
| Ingredient Mineral | Cone 6 Satin White Matte (%) | Cone 10 Celadon Reduction (%) | Cone 10 Oil Spot Tenmoku (%) |
|---|---|---|---|
| Custer Potash Feldspar | 20.0% | 38.0% | 42.0% |
| Silica (Flint 325#) | 28.0% | 28.0% | 26.0% |
| Whiting (Calcium Carbonate) | 16.0% | 18.0% | 14.0% |
| EPK Kaolin | 18.0% | 12.0% | 8.0% |
| Strontium Carbonate / Wollastonite | 12.0% | 0.0% | 0.0% |
| Dolomite / Talc | 6.0% | 4.0% | 0.0% |
| Red Iron Oxide (Fe₂O₃) | 0.0% | 1.2% (Pale Sea-Green) | 9.5% (Metallic Rust Crystals) |
| Tin Oxide / Zircopax | 4.0% (Opaque white) | 0.0% | 0.0% |