I read this in another link from Farss ( Bob ) and thought it interesting enough to repost here:
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To scuplt foam rubber freeze it first. The stuff ends up like wood. A dark secret I learned from the guys who make props.
You do need to get it really cold, around -20 C or lower, at a pinch hit it with a CO2 extinguisher.
Bob.
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Now my addition:
I use an electric kitchen knife to cut my foam rubber. It does a great job - infinitely better and faster than hacking away with a regular blade and/or scissors.
v