Has concrete been used as a permanent mold for casting aluminum and other nonferrous metals?
Concrete has not been used as a permanent mold for casting aluminum and other nonferrous metals and we would recommend against its use. The basic reason for this is that the temperature of the molten metal (about 1200 degrees F) may cause spalling of the concrete and excessive volume changes will occur because of temperature changes of the mold as the molten material cools. However, experimental work is presently underway on the use of regulated-set cement and sand for making of foundry molds. These, of course, are single-use molds. Information regarding regulated-set concrete is available from the Portland Cement Association, Old Orchard Road, Skokie, Illinois 60076.