- Strong alkaline flux
- Similar to sodium oxide except
- Slightly weaker
- Begins fluxing action earlier than sodium oxide, at about 1382°F
- Predictable, stable flux
- Produces bright glossy glazes
- Can’t be used alone as a flux
- It produces slightly stronger glaze surfaces than sodium oxide
- Low viscosity and surface tension creates fluid glaze melts
- High coefficient of expansion and contraction may cause crazing
- Often found combined with sodium oxide, so commonly written as KNaO
- Only slightly volatile at ceramic temperatures
- Slightly soluble
- Usually used in its insoluble forms like feldspars or slightly soluble Frits
- Can be introduced to glaze recipe as a soluble like pearl ash (potassium carbonate), which can cause flashing like sodium carbonate.
- Insoluble sources are
- Potash feldspars
- Custer
- G-200
- K-200
- A-3
- Kona F-4
- Cornwall Stone
- plastic Vitrox
- Volcanic ash
- Kona A-1
- Bell
- Eureka
- A-200
- Mica
- Potash feldspars
- All soda feldspars have some potassium oxide
- Frits
- P-25
- 3110
- 3124
- Soluble forms include pearl ash (K2CO3), potassium nitrate )saltpeter), and unwashed wood ash
- Frits