Low Expansion Frit (Potclays 2279)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Frits
- Formula
- Li₂O 1.1%, CaO 3.6%, ZnO 3.3%, MgO 2.4%, Al₂O₃ 8.2%, SiO₂ 63.6%, B₂O₃ 17.8%
- Also called
- Low Expansion Frit, Potclays 2279, Bath Potters LOEF
- Sold in
- UK
- Similar materials
- Low Expansion Frit (Potterycrafts P2960)
- Source
- Potclays, 'Frit Formulae' technical sheet (John Beeston, January 2010), Internet Archive copy of 2013 (2010-01)
Leadless low-expansion frit; small additions raise a glaze's craze resistance, large amounts give milkiness. Firing range 1020-1150 °C (Bath Potters) or 1040-1100 °C (Potclays). Potclays' sheet, and Bath Potters after it, prints Li₂O 0.10, which leaves the analysis at 99.0%. Potclays' own formula on the same sheet (0.176 Li₂O) gives 1.06%, as the near-identical Potterycrafts P2960 does, so 1.1 is used.
Oxide analysis and unity formula
Glazecalc has the analysis of Low Expansion Frit (Potclays 2279) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Low Expansion Frit (Potclays 2279) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| Li₂O | 1.1 | 0.183 |
| CaO | 3.6 | 0.319 |
| ZnO | 3.3 | 0.202 |
| MgO | 2.4 | 0.296 |
| Al₂O₃ | 8.2 | 0.400 |
| SiO₂ | 63.6 | 5.263 |
| B₂O₃ | 17.8 | 1.271 |
- Equivalent weight
- 497.24
- Fired weight
- 497.24
- Loss on ignition
- 0%
The equivalent weight is the grams of Low Expansion Frit (Potclays 2279) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Not classified (equivalent Potterycrafts P2960 SDS); avoid breathing the dust.
Use it in a recipe
Add Low Expansion Frit (Potclays 2279) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.