Glaze material · Fluxes, feldspars & frits
Ferro frit 3249
Also sold as: frit 3249
A magnesium borosilicate frit with a low coefficient of expansion.
In published recipes
Used in 21 of 10,859 glaze recipes (0.2%)
Typical amount when present
13% of the dry batch — half of recipes fall between 5.6% and 19.5%.
Fired surface of those recipes
Glossy 69% · Satin matte 13% · Matte 13% · Smooth matte 6%
Most often mixed with
Materials that appear in the same recipes most often.
What potters should know
Reached for to fight crazing and in glazes for flameware and ovenware.
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 Ferro frit 3249 do potters use in a glaze?
- Across 21 published glaze recipes containing it, the typical amount is 13% of the dry batch, with half of recipes between 5.6% and 19.5%. 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 Ferro frit 3249 used at?
- It appears in recipes across the range; the most common cones among published recipes are cone 6, cone 5, cone 7. Where a material sits depends on the rest of the recipe more than on the material itself.
- Is Ferro frit 3249 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 |
|---|---|---|
| Ferro frit 3134 | 1,907 | 20% |
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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