OM #4 Ball Clay

Alternate Names: OM4 Ball Clay, OM4, OM#4, OM 4, Old Mine #4, OM-4 Ball Clay

Description: Tennessee Ball Clay

Oxide	Analysis	Formula
CaO	0.20%	0.01
K2O	1.10%	0.05
MgO	0.50%	0.05
Na2O	0.20%	0.01
TiO2	2.00%	0.10
Al2O3	26.30%	1.00
SiO2	59.70%	3.85
Fe2O3	1.30%	0.03
LOI	9.30%	n/a
Oxide Weight		354.09
Formula Weight		390.40

Notes

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.

Physical Properties
===================
Water of Plasticity: 32.8%
% Dry Shrinkage: 6.2
Dry M.O.R. (50:50 ball clay:silica, psi): 610
pH: 4.0
M.B.I. (meq/100g): 9.2
Specific Surface Area (sq-metre/g): 23.1
Soluble sulphur SO₄: Low

P.C.E.: 32

Particle Size, Microns: 20 10 5 2 1 0.5
(% finer than) 96% 91% 83% 68% 57% 46%

Fired Properties
================
Cone 5 10
Total Shrinkage: 11.3% 13.6%
Absorption: 11.1% 4.2%

Shipped from Mayfield, KY

*This info is from a data sheet from Jan 2013

Related Information

OM4 Ball clay fired from cone 10R (top), 10 down to 4 (downward)

Ball clays are normally refractory, none of these are vitrified to any extent. The cone 10R bar is yellow because it is stained by the soluble salts present in the material. These are very typical of what most ball clays look like.

Links

Typecodes	Ball Clay Ball clays are abundant and very plastic and are used in all types of plastic forming bodies. They are not as white-burning or refractory as kaolins but lower in iron and fluxes than bentonites.
Materials	Gleason Ball Clay

Data

Pyrometric Cone Equivalent	31

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