Defect · Drying
Rim crack
Also called: lip crack
Cracks radiating from or along the rim of a thrown vessel, usually appearing during the leather-hard to bone-dry transition.
- Appears at
- Drying
- Severity
- Structural
- How common
- Common
Causes
Most likely
- ·Rim drying faster than the body of the piece
- ·Uneven wall thickness
Prevention
- ·Cover rims loosely with plastic during the first 12-24 hours of drying
- ·Compress the rim with a chamois or soft rib after throwing
Can it be fixed?
- ·At leather-hard, paint the crack with slip of the same clay body and burnish closed
Questions
- Why does rim crack happen?
- Most often: Rim drying faster than the body of the piece. Other causes: Uneven wall thickness..
- Can rim crack be fixed?
- Sometimes. At leather-hard, paint the crack with slip of the same clay body and burnish closed.
- How do I prevent rim crack?
- Cover rims loosely with plastic during the first 12-24 hours of drying. Compress the rim with a chamois or soft rib after throwing.
Further reading. The industrial treatment of this defect in the Ceramicware Defects Handbook on Wikibooks (CC BY-SA 3.0).
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.
Not sure which defect you're looking at?
Claybench can read a photo of the pot against this same reference and rank the likely causes for your clay, glaze and firing.