|Monthly Tech-Tip |
These two glazes have very similar chemistries (except that G2931G has a much lower SiO2 content, that is why it is melting better). Left: 0.75 molar boron is being sourced by a high quality frit in G3879C, Fusion Frit F-524. Right: Ulexite is sourcing the same 0.75 boron. Ulexite is a natural material (it is mostly ulexite, but does have other contaminants). Unlike the frit, it contains volatiles that produce an LOI on firing, these gases are generated during the melting phase, producing obvious bubbling.