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. OM#4 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. - Digital Fire ceramic materials database
Ball Clays are a secondary, transported (sedimentary) clay which are very plastic and fire to a pale color... They have a high shrinkage rate and are difficult to handle on their own due to a very fine particle size.... - p. 14, Illustrated Dictionary of Practical Pottery, 3rd Ed. by Robert Fournier
Ball Clays are a secondary, transported (sedimentary) clay which are very plastic and fire to a pale color... They have a high shrinkage rate and are difficult to handle on their own due to a very fine particle size.... - p. 14, Illustrated Dictionary of Practical Pottery, 3rd Ed. by Robert Fournier
50# bag; brown bag, red text OM4 printed on side
