What results from excessive flux oxides in a glaze?

Unit 2 Topic 4
The Glaze Triangle
Excessive flux causes a glaze to run and tends to create variable texture on the surface.

 

The texture may vary from shiny, where the glass is balanced, to matt where excessive flux oxides may form visible, possibly lumpy, crystals.

The glaze represented by the example model in the diagram might be runny at certain temperatures and could be patchy with areas of clear glaze interspersed with matt opaque areas where crystals have developed around the free CaO molecules not bound with Al2O3 and SiO2 into glass structures.

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