"Wayne Lundberg" wrote in message
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I imagine you burn out the foam the same as you would the wax? How do you
maintain a nice slick surface finish without using self skinning urethane
foams?


Dry sand is poured around the pattern, which is foam board (pink or blue
insulation board) or a pattern made from polystyrene bead, and then the
metal is introduced, which burns away the form and replaces it. It sounds
like it wouldn't work, but they're doing some pretty decent casting that
way.

Harold