Synthetic Isu Ash (合成柞灰)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Fluxes
- Formula
- SiO₂ 17.59%, Al₂O₃ 3.13%, Fe₂O₃ 0.31%, CaO 37.09%, MgO 5.25%, Na₂O 0.06%, K₂O 0.17%, LOI 36.4%
- Also called
- 合成柞灰, 合成イス灰, gōsei isubai
- Sold in
- JP
- Source
- 佐賀県陶磁器原料株式会社 (Arita): 釉薬原料の化学分析表, the supplier's typical analysis of what it sells (undated; read 2026-11-04)
A typical analysis from one supplier in Arita: check it against your own supplier's. A synthetic stand-in for 柞灰 (isu ash), a wood ash of Japanese glazes; it is not real ash, which varies a great deal. The supplier's figures add up to 96.48%, so the 3.52% they leave out is counted here as lost on firing, with its LOI of 32.88%.
Oxide analysis and unity formula
Glazecalc has the analysis of Synthetic Isu Ash (合成柞灰) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Synthetic Isu Ash (合成柞灰) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 17.59 | 0.369 |
| Al₂O₃ | 3.13 | 0.039 |
| Fe₂O₃ | 0.31 | 0.002 |
| CaO | 37.09 | 0.833 |
| MgO | 5.25 | 0.164 |
| Na₂O | 0.06 | 0.001 |
| K₂O | 0.17 | 0.002 |
- Equivalent weight
- 125.87
- Fired weight
- 80.06
- Loss on ignition
- 36.4%
The equivalent weight is the grams of Synthetic Isu Ash (合成柞灰) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Avoid breathing the dust.
Use it in a recipe
Add Synthetic Isu Ash (合成柞灰) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.