L3685U slurry was applied to the insides of both of these mugs. But on the left it is a "slip", on the right an "engobe". Why? The left mug only has a thin layer, applied by painting a gummed version on (at leather hard stage). On the right a gelled slurry was poured into the leather hard piece, poured out and the rim dipped (creating a much thicker layer with more power to impose its own drying and firing shrinkage). So it is much more important that the latter be compatible with the underlying body. The EBCT test is used to measure how compatible the body and engobe are.
Engobes are high-clay slurries that are applied to leather hard or dry ceramics and fire opaque. They are used for functional or decorative purposes.
The term Slip can have various meanings in traditional ceramics.
|Tests||Engobe Body Compatibility Test|