How much Kona F-4 feldspar do potters use in a glaze?

Across 601 published glaze recipes containing it, the typical amount is 32% of the dry batch, with half of recipes between 16.7% and 44%. 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 Kona F-4 feldspar 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 Kona F-4 feldspar 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

Kona F-4 feldspar

Also sold as: F-4

The classic soda feldspar in North American recipes — flux, alumina and silica with a sodium bias.

fluxglass formerstiffens the melt (alumina)Contributes: Na₂O · K₂O · Al₂O₃ · SiO₂

In published recipes

Used in 601 of 10,859 glaze recipes (5.5%)

Typical amount when present

32% of the dry batch — half of recipes fall between 16.7% and 44%.

Fired surface of those recipes

Glossy 46% · Matte 22% · Satin matte 18% · Semi-glossy 14%

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.

Silica63%EPK61%Whiting46%Ball clay33%Bentonite33%Dolomite32%Nepheline syenite24%Red iron oxide23%

Chemistry

Raw formula: Na₂O·Al₂O₃·6SiO₂
Molecular weight: 524
Fired formula: Na₂O·Al₂O₃·6SiO₂
Equivalent weight: 524
: idealized soda feldspar

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

No longer mined. Substitute Minspar 200 in old recipes.

Handling and safety

Crystalline silica: the primary respiratory hazard in a ceramic studio (silicosis with chronic exposure). Wet processes, ventilation and a fitted respirator when dry.

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 Kona F-4 feldspar do potters use in a glaze?: Across 601 published glaze recipes containing it, the typical amount is 32% of the dry batch, with half of recipes between 16.7% and 44%. 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 Kona F-4 feldspar 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 Kona F-4 feldspar 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
Minspar 200	418	33%
Soda feldspar	660	30%

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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