Calcium Chloride Flake is used as a flocculating agent in glazes (to suspend and gel them). For many, especially larger manufacturers, it is the product of choice (more effective than epsom salts and vinegar). It works well with glazes containing bentonite or carbonates. This material is the key to being able to apply a glaze to non-porous porcelain bisque ware, the slurry stays in place after application because of the gel state.
Usually small additions (.1-.3%) added to glaze slurries are sufficient to produce gelling. But sometimes higher, or considerably higher, percentages are needed (which may be an important consideration if small amounts of epsom salts would work).
Calcium Chloride Flake is hygroscopic and needs to be kept in a sealed container otherwise it will absorb the moisture from the air.
Glaze Suspender - General
Gels glaze slurries.