The thin ridge of excess clay that seeps into the joint between mold sections during slip casting or pressing. If left on the greenware, it becomes a sharp, unsightly flaw after firing. Workers must trim and sponge away this seam while the clay is still leather-hard, a process itself known as fettling.
Heard on the job
You missed a fettle on the handle of this mug and now it feels sharp in the hand.
Insider tip
Always use a flexible fettling knife and a damp sponge to smooth the fettle, rather than sanding it dry, to avoid creating hazardous clay dust.
Also heard as
- seam line
- mold mark