Gillespie Borate
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Boron sources
- Formula
- SiO₂ 11.8%, Al₂O₃ 1.7%, B₂O₃ 24.5%, CaO 23%, MgO 3.9%, SrO 0.45%, K₂O 0.01%, Na₂O 3.77%, LOI 30.9%
- Also called
- Gillespie Borate - Natural (CTM)
- Made by
- Hammill & Gillespie Inc. (Chatham, New Jersey, USA)
- Sold in
- US, UK, EU
- Similar materials
- Gerstley Borate
- Replaces
- Gerstley Borate
- Source
- Hammill & Gillespie, 'Gillespie Borate Fact Sheet', Chemical Analysis [Typical] (PDF created 2011-04-25; copy hosted by Kerasil, Finland) (2011-04)
Blended borate (mainly ulexite with some colemanite and about 10% clay-like material) made as a pound-for-pound replacement for Gerstley Borate; currently produced and sold in the US, UK and Europe.
Oxide analysis and unity formula
Glazecalc has the analysis of Gillespie Borate as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Gillespie Borate that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 11.8 | 0.343 |
| Al₂O₃ | 1.7 | 0.029 |
| B₂O₃ | 24.5 | 0.615 |
| CaO | 23 | 0.717 |
| MgO | 3.9 | 0.169 |
| SrO | 0.45 | 0.008 |
| K₂O | 0.01 | 0.000 |
| Na₂O | 3.77 | 0.106 |
- Equivalent weight
- 174.77
- Fired weight
- 120.76
- Loss on ignition
- 30.9%
The equivalent weight is the grams of Gillespie Borate that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Borate: do not ingest; high-dose animal studies of inorganic borates show reproductive/developmental effects (U.S. Borax Gerstley Borate MSDS, Apr 2013). Avoid breathing dust.
Use it in a recipe
Add Gillespie Borate to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.