Monthly Tech-Tip | No tracking! No ads! |
This rutile glaze is running down on the inside, so it has a high melt fluidity. "High melt fluidity" is another way of saying that it is being overfired to get the visual effect. It is percolating at top temperature (during the temperature-hold period), forming bubbles. There is enough surface tension to maintain them for as long as the temperature is held. To break the bubbles and heal up after them the kiln needs to be cooled to a point where decreasing melt fluidity can overcome the surface tension. Where is that? Only experimentation will demonstrate, try dropping a little more (e.g. 25 degrees) over a series of firings to find a sweet spot. The hold temperature needs to be high enough that the glaze is still fluid enough to run in and heal the residual craters. A typical drop temperature is 100F.
Troubles |
Runny Ceramic Glazes
Glazes of high melt fluidity are likely to run if applied to thickly or have not catcher glaze |
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Troubles |
Glaze Blisters
Questions and suggestions to help you reason out the real cause of ceramic glaze blistering and bubbling problems and work out a solution |
Glossary |
Fluid Melt Glazes
Fluid melt glazes and over-melting, over fired, to the point that they run down off ware. This feature enables the development of super-floss and cyrstallization. |
Glossary |
Melt Fluidity
Ceramic glazes melt and flow according to their chemistry, particle size and mineralogy. Observing and measuring the nature and amount of flow is important in understanding them. |
Glossary |
Rutile Blue Glazes
A type of ceramic glaze in which the surface variegates and crystallizes on cooling in the presence of titanium and iron (usually sourced by rutile) |
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