Alternate Names: OM4 Ball Clay, OM4, OM#4, OM 4, Old Mine #4, OM-4 Ball Clay
Old Mine #4, Mayfield, KY.
A fine-grained ball clay with excellent plasticity and strength. Old Mine #4 is an "industry standard" based on its popularity in both casting and plastic formed bodies. It is also widely used as a suspension aid in glazes.
Ball clay is variable in nature and tends to be more vitreous than some of the more refractory ball clays that are available. It has some soluble salts which can give a brown coloration to the surface, so barium, carbonate may be needed to precipitate these.