claybench

Reference

Glaze materials

What each raw material does in a glaze, how much of it potters actually use, and at which cones — computed across 10,859 published glaze recipes — with the studio hazards you should know.

Figures are aggregates over many published recipes, not recommendations. Always test.

Glass former

The backbone of every glaze — silica melts with the fluxes into glass.

Silica8,070 recipes · typical 20%

Clays

Alumina and silica in a form that suspends the bucket and stiffens the melt.

EPK4,397 recipes · typical 11.7%Kaolin2,677 recipes · typical 11%Ball clay1,683 recipes · typical 11.4%Calcined kaolin285 recipes · typical 12%Grolleg kaolin255 recipes · typical 12.1%Redart195 recipes · typical 27%Albany slip163 recipes · typical 60%Barnard slip75 recipes · typical 20%Alberta slip60 recipes · typical 51%

Fluxes, feldspars & frits

What brings the melting point down to your cone; the choice of flux shapes surface and colour response.

Whiting5,462 recipes · typical 12.5%Nepheline syenite3,138 recipes · typical 30%Dolomite2,402 recipes · typical 10%Custer feldspar2,210 recipes · typical 37.5%Zinc oxide2,144 recipes · typical 5.5%Talc1,975 recipes · typical 8.1%Gerstley borate1,926 recipes · typical 14.5%Ferro frit 31341,907 recipes · typical 20%Potash feldspar1,446 recipes · typical 36%Wollastonite1,298 recipes · typical 15%Lithium carbonate1,064 recipes · typical 4.1%Barium carbonate948 recipes · typical 12%Strontium carbonate757 recipes · typical 12%Spodumene721 recipes · typical 15.6%Bone ash681 recipes · typical 7%Ferro frit 3124675 recipes · typical 30%Soda feldspar660 recipes · typical 30%Kona F-4 feldspar601 recipes · typical 32%Soda ash469 recipes · typical 5%Minspar 200418 recipes · typical 33%Ferro frit 3110408 recipes · typical 30.2%Magnesium carbonate384 recipes · typical 5.5%Cornwall stone330 recipes · typical 37.3%G-200 feldspar320 recipes · typical 34%Colemanite293 recipes · typical 12.9%Wood ash277 recipes · typical 31.1%Ferro frit 3195275 recipes · typical 23%Gillespie borate215 recipes · typical 13.5%Borax143 recipes · typical 12%Petalite89 recipes · typical 15%Ferro frit 324921 recipes · typical 13%

Opacifiers

Turn a clear glaze white or milky.

Tin oxide1,345 recipes · typical 4%Zircopax1,098 recipes · typical 9.4%Titanium dioxide1,036 recipes · typical 4.6%

Colorants

Metal oxides and carbonates that give a glaze its colour; most need care in handling.

Red iron oxide2,413 recipes · typical 4%Copper carbonate1,779 recipes · typical 3%Rutile1,518 recipes · typical 4%Cobalt carbonate1,181 recipes · typical 1%Chrome oxide648 recipes · typical 0.5%Cobalt oxide604 recipes · typical 1%Manganese dioxide534 recipes · typical 3%Copper oxide445 recipes · typical 2%Ceramic stains266 recipes · typical 7%Nickel oxide201 recipes · typical 1.5%Yellow ochre148 recipes · typical 5%Silicon carbide125 recipes · typical 1%Yellow iron oxide119 recipes · typical 2%Black iron oxide81 recipes · typical 2.8%Ilmenite52 recipes · typical 2%

Additives

Small amounts that fix suspension, brushing, and settling without changing the fired result.

Bentonite2,907 recipes · typical 2%Alumina112 recipes · typical 8.2%Epsom salts103 recipes · typical 1%CMC gum68 recipes · typical 0.5%

Restricted — read before using

Toxic in the studio and regulated on food surfaces. Listed for reference — Claybench does not recommend them.

Lead compounds47 recipes · typical 55%Cadmium compounds0 recipes

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.

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.