The production, properties and casting potential of a clay/oil-bonded foundry moulding sand

An investigation has been carried out into the use of an organo-clay as a bonding medium for foundry sand moulds. The method and means of the modification of a naturally occurring Na bentonite to an oleophilic organo-clay, dimethyldioctadecylammonium bentonite, have been researched and the findings reported. The physical properties of moulding sands bonded with the organo-clay and a light mineral oil have been investigated and the effects of varying the clay content, oil content, mulling temperature, mulling time, polar material additions and mould temperature have been reported. The effects upon the physical properties have also been studied when storing the mulled sand, using it over a number of casting cycles and making restorative additions of clay and oil after its use. Finally, castings produced in moulds bonded with the organo-clay have been made in an aluminium–magnesium alloy, phosphor–bronze and in cast iron, and the surface finish, dimensional accuracy and casting soundness monitored.