Glaze material · Fluxes, feldspars & frits
Wood ash
A natural flux and glass former: calcium, potassium and phosphorus with silica and traces of everything.
In published recipes
Used in 277 of 10,859 glaze recipes (2.5%)
Typical amount when present
31.1% of the dry batch — half of recipes fall between 15.3% and 45.1%.
Fired surface of those recipes
Glossy 48% · Semi-glossy 25% · Matte 16% · Satin matte 11%
Most often mixed with
Materials that appear in the same recipes most often.
What potters should know
Variable by species and washing; potters test each batch. Washing removes soluble alkalis and makes it safer to handle.
Handling and safety
Soluble in water — can migrate to the surface as it dries and irritate skin; handle with gloves and keep out of food-contact glazes unless fritted.
Dry ceramic materials generate respirable silica dust. Use a NIOSH-approved N95 or P100 respirator and adequate ventilation when mixing dry, and wet-clean surfaces.
This information is provided for planning purposes and is derived from publicly available sources including OSHA regulations, NIOSH guidance, and manufacturer safety data sheets. It does not constitute professional safety advice. Consult your material suppliers' SDS documents and applicable local regulations for authoritative safety guidance.
Questions
- How much Wood ash do potters use in a glaze?
- Across 277 published glaze recipes containing it, the typical amount is 31.1% of the dry batch, with half of recipes between 15.3% and 45.1%. Colorants and additives sit far lower than fluxes and glass formers; treat these as a range to test around, not a target.
- What cone is Wood ash used at?
- It appears in recipes across the range; the most common cones among published recipes are cone 10, cone 6, cone 9. Where a material sits depends on the rest of the recipe more than on the material itself.
- Is Wood ash safe to use?
- It carries a specific hazard flag: Soluble in water — can migrate to the surface as it dries and irritate skin; handle with gloves and keep out of food-contact glazes unless fritted. Read the supplier's SDS and follow local rules before using it, and never assume a glaze is food-safe without testing.
Related materials
| Glaze material | recipes | typical |
|---|---|---|
| Whiting | 5,462 | 12.5% |
Sources. Usage figures are computed by Claybench over 10,859 glaze recipes compiled from publicly shared community recipe collections (snapshot 2026-02-27) — counts only; no recipe is reproduced, and the figures describe that collection, not every recipe in existence. Material roles and notes are paraphrased from Linda Arbuckle's Ceramic Materials handout unless noted. Hazard notes summarise supplier SDS guidance; read the SDS for the product you buy.
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