ADAPTATION OF LOCAL POTTER'S CLAYS FOR CORE - MAKING

Abstract

The suitability of Igbara Odo and lsau Ekiti days for core making has been studied by testing their coring properties in the as-mined states. Consequent upon their' unsuitability in tlhe as mined states, they were thereafter adapted for foundary use in order for them to meet the standard values of the core mixture in use in reputable foundry workshop such a the Nligerian Machine Tools(NMT), Oshogbo by adding Igbokoda silica dust and cassava starch in varying percentages ranging from 10_100% I - 6%, and 0.5 - 3.% respectively. The coring properties tested include: green compression strength, baked permeability, dry compression and shear strengths, hot and baked strengths, baked haked hardness and bulk, densities .3.4. 5 and 6 blows of the rammer. The core mixture in use at the NMT was also tested for all these properties and the results obtained used as the reference values. After detailed tests and comparisons, the following compositions were ' found to conform closely with the reference values after igbokoda silica sand 2% saw dust1.5% starch.