These two transparent glazes are opposites: In melt fluidity and surface tension

Thursday 16th June 2016

This insight-live.com/glossary/119">cone 04 flow tester compares two commercial low-fire transparent glazes. Their different chemistry strategies are revealed by the shape of these melt flows. While 3825B appears to have the higher melt fluidity, it also has much higher melt surface tension. This is evident in the narrow, rope-like stream and the way the flow meets the runway at a high angle before pulling into a rounded bead. A, by contrast, spreads and wets the runway, meandering downward in a broad, flat and relatively bubble-free river.

This difference is important in low-fire ware because these glazes must pass far more gases and bubbles than high-temperature glazes. The lower surface tension of A aids bubble release and healing after bubbles break. A is Amaco LG-10. B is Crysanthos SG213 (Spectrum 700 behaves similarly, although flowing less). Both approaches have advantages and disadvantages and are worth testing in your application.

Pages that reference this post in the Digitalfire Reference Library:

Ulexite, High and low melt surface tension: As demonstrated by two pure frits, Surface tension differences between two glazes: This simple test shows them best, The perfect storm of high surface tension and high LOI: Blisters., Surface Tension, Melt Fluidity, Transparent Glazes, Terra Cotta, Glaze Blisters, Clouding in Ceramic Glazes

This post is one of thousands found in the Digitalfire Reference Database. Most are part of a timeline maintained by Tony Hansen. You can search that timeline on the home page of digitalfire.com.