(Popular Mechanics, January 1945, page 145)
"In casting small objects from soft metals, I have four that portland cement mixed with silicate of soda provides good molds for the work. Enough soda is used to make a mixture of the right consistency for easy shaping of the molds. Such molds stand up well for casting toys, small statuary, etc. I have also used them for casting aluminum and zinc as well as brass."
[illustration of a normal cope and drag two piece mold]
PM: casting in concrete
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