How much Whiting do potters use in a glaze?

Across 5,462 published glaze recipes containing it, the typical amount is 12.5% of the dry batch, with half of recipes between 7.8% and 18%. 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 Whiting used at?

It appears in recipes across the range; the most common cones among published recipes are cone 6, cone 10, cone 9. Where a material sits depends on the rest of the recipe more than on the material itself.

Is Whiting safe to use?

It carries no specific hazard flag beyond the general rule for all dry ceramic materials: avoid breathing the dust and read the supplier's SDS.

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Glaze material · Fluxes, feldspars & frits

Whiting

Also sold as: calcium carbonate, chalk, limestone

The main source of calcium, the alkaline-earth flux, in glazes. Helps make hard glazes.

fluxContributes: CaO

In published recipes

Used in 5,462 of 10,859 glaze recipes (50%)

Typical amount when present

12.5% of the dry batch — half of recipes fall between 7.8% and 18%.

Fired surface of those recipes

Glossy 59% · Matte 16% · Semi-glossy 15% · Satin matte 11%

Cones where it appears

Share of recipes containing this material that fire to each cone.

Most often mixed with

Materials that appear in the same recipes most often.

Silica85%EPK44%Custer feldspar30%Bentonite28%Red iron oxide27%Kaolin27%Zinc oxide27%Nepheline syenite25%

Chemistry

Raw formula: CaCO₃
Molecular weight: 100
Fired formula: CaO
Equivalent weight: 100

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

In excess it matts the surface. Whiting releases carbon dioxide as it fires — recipes plagued by pinholes sometimes swap part of it for wollastonite.

Handling and safety

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 Whiting do potters use in a glaze?: Across 5,462 published glaze recipes containing it, the typical amount is 12.5% of the dry batch, with half of recipes between 7.8% and 18%. 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 Whiting used at?: It appears in recipes across the range; the most common cones among published recipes are cone 6, cone 10, cone 9. Where a material sits depends on the rest of the recipe more than on the material itself.
Is Whiting safe to use?: It carries no specific hazard flag beyond the general rule for all dry ceramic materials: avoid breathing the dust and read the supplier's SDS.

Related materials

Glaze material	recipes	typical
Dolomite	2,402	10%
Wollastonite	1,298	15%
Bone ash	681	7%

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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