Monthly Tech-Tip | No tracking! No ads! |
These glazes have not just crazed or shivered, they have pulled part of the body with them. What can generate forces great enough to create failures between glaze and body like this? Differential thermal expansion. Consider:
First, the glaze is thick. Very thick. Much too thick.
Second: A strong body:glaze interface zone has developed. That's good.
Third: The body is not firing to optimal strength (it appears porous). Not necessarily bad if the glaze fits.
What to do? Apply the glaze thinner, of course. But, testing should also be done to determine whether the glaze is under compression or tension. This could be done using the EBCT test.
Glossary |
Co-efficient of Thermal Expansion
The co-efficient of thermal expansion of ceramic bodies and glazes determines how well they fit each other and their ability to survive sudden heating and cooling without cracking. |
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