Why do gummed dipping glazes do this as they dry? How to fix it.

Gummed glazes dry slowly and on porous, dry bisque this often happens. The one on the top left was dipped for three seconds, and the ones on the top right and bottom right for five seconds. Thus, the thicker the application the worse this is. A complicating factor is that this is a base-coat dipping glaze, it has enough gum to slow down drying significantly, providing plenty of time for escaping air, displaced by the water being absorbed, to create these holes. If these tiles were much thinner the problem would obviously be much less. But the thickness also enables a simple solution: The bottom left tile was dipped into water first. An extra benefit of the water is that the glaze penetrates into recesses in the surface better.

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Links

URLs	https://www.zschimmer-schwarz.com/en/ceramic-auxiliaries/tiles/glaze-additives/wetting-agents Wetting agents from zschimmer-schwarz.com: Surfactants that reduce the surface tension of aqueous glaze systems.
URLs	https://en.wikipedia.org/wiki/Surfactant Surfactants at Wikipedia
Glossary	Surface Tension In ceramics, surface tension is discussed in two contexts: The glaze melt and the glaze suspension. In both, the quality of the glaze surface is impacted.
Glossary	Glaze laydown Refers to the quality of the dried ceramic glaze layer and how this affects the fired result: e.g. density, hardness, evenness, thickness, freedom from defects, etc.

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