I find i always have trouble cutting thick insulation foam with a razor knife so i was wondering whats the best way to cut it? With what type of tool? A hot knife? Hot wire cutter?
Hotwire Foam Factory - I use their hot knife and freehand router. I've also used an electric turkey carving knife for softer foams. Shaping with a flap wheel on a 4.5 inch angle grinder.