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Defect · Glaze firing
Kiln wash adhesion
Also called: shelf stick, stuck to shelf
Form is fused to the kiln shelf by glaze that ran off the foot.
- Appears at
- Glaze firing
- Severity
- Affects function
- How common
- Common
Causes
Most likely
- ·Glaze applied too close to the foot
- ·Glaze ran during firing
- ·Kiln shelf not adequately washed
Prevention
- ·Apply kiln wash (alumina + kaolin) to shelves regularly
- ·Keep foot of piece glaze-free
Can it be fixed?
- ·Gently tap to free; grind residual shelf material off the foot
Related defects
Questions
- Why does kiln wash adhesion happen?
- Most often: Glaze applied too close to the foot. Other causes: Glaze ran during firing. Kiln shelf not adequately washed..
- Can kiln wash adhesion be fixed?
- Sometimes. Gently tap to free; grind residual shelf material off the foot.
- How do I prevent kiln wash adhesion?
- Apply kiln wash (alumina + kaolin) to shelves regularly. Keep foot of piece glaze-free.
Sources. Compiled from Claybench's defect reference — the descriptions, causes and remedies that appear consistently across standard ceramics references and studio practice; no single source. It is the same reference the photo diagnosis tool reasons over. Where the Wikibooks Ceramicware Defects Handbook covers a defect it is linked above.
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