Journal of Minerals & Materials Characterization & Engineering , Vol. 10, No.15, pp.1449-1455, 2011 jmmce.org Printed in the USA. All rights reserved 1449 Effect of Varying Corn Cob and Rice Husk Ashes on Properties of Moulding Sand Sunday Aribo Department of Metallurgical and Materials Engineering Federal University of Technology, PMB 704, Akure, Nigeria Corresponding Author: aribosunny@yahoo.com ABSTRACT The use of rice husk and corn cob ashes as aggregates for foundry moulding sand has been studied. 5-12.5 weight percent of rice husk and corn cob ashes were added to the sand mixture and the sand properties determined. A mixture of equal proportion of rice husk and corn cob ashes was also used. In each case, four weight percent water and clay were added to the sand mixture. Some of the properties of the sand tested are: permeability, green compression strength, dry compression strength, green shear strength, dry shear strength, moisture content and permeability. The results showed that the green compression strength, green shear strength, moisture content and permeability decrease with increase in the additives (rice husk ash, corn cob ash, and (50% rice husk and 50% corn cob ashes). While dry compression strength and dry shear strength increase with increase in weight percent of the additives. Key words: moulding sand, rice husk, corn cob, ashes, sand properties. 1. INTRODUCTION The urgent need to develop the foundry industries in Nigeria in order to meet the technological development of the country has led to so much interest in the characterization of the locally available materials. Silica sand is an extremely good material for making casting moulds because it has the ability to withstand the temperature of the molten metal. It can absorb and transmit heat, and has sufficient permeability to allow gasses generated during casting to pass between the particles without causing casting defects. Foundry sand is made within strict particle size distribution to tailor the properties of the materials to the intended casting process [1]. There are many deposits of silica sand for foundry application scattered all over Nigeria. Investigation shows that silica sand are abundant in Ogun, Ondo and Lagos states of the western