Glaze material · Fluxes, feldspars & frits
Soda ash
Also sold as: sodium carbonate
A soluble source of sodium — a strong alkaline flux with brilliant colour response and high expansion.
In published recipes
Used in 469 of 10,859 glaze recipes (4.3%)
Typical amount when present
5% of the dry batch — half of recipes fall between 3.3% and 10%.
Fired surface of those recipes
Glossy 51% · Semi-glossy 27% · Satin 12% · Smooth matte 10%
Most often mixed with
Materials that appear in the same recipes most often.
Chemistry
- Raw formula
- Na2CO3
- Molecular weight
- 106
- Fired formula
- Na2O
- Equivalent weight
- 106
From Linda Arbuckle's materials table. Mineral formulas are idealized; buy an analysis for the bag you have. Equivalent weight is the weight that supplies one molecule of the fired oxide — the number glaze calculation uses.
What potters should know
High amounts craze, and sodium as a major flux makes a mechanically soft glaze. Deflocculates. Ultramarine with cobalt, turquoise with copper, chartreuse with chrome, plum with manganese.
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 Soda ash do potters use in a glaze?
- Across 469 published glaze recipes containing it, the typical amount is 5% of the dry batch, with half of recipes between 3.3% and 10%. 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 Soda ash used at?
- It appears in recipes across the range; the most common cones among published recipes are cone 10, cone 9, cone 6. Where a material sits depends on the rest of the recipe more than on the material itself.
- Is Soda 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 |
|---|---|---|
| Borax | 143 | 12% |
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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