M370 mug using M370 clear glaze by Victor Duffhues.
Creating a Non-Glaze Ceramic Slip or Engobe
It can be difficult to find an engobe that is drying and firing compatible with your body. It is better to understand, formulate and tune your own slip to your own body, glaze and process.
The flocculation process enables technicians in ceramics to create an engobe or glaze slurry that gels and goes on to the ware in a thick yet even layer that does not drip.
Glaze slurries can gel if they contain soluble materials that flocculate the suspension. Gelling is a real problem since it requires water additions that increase shrinkage.