you just like re-inventing wheels Denny wink a cheap Olfa knife with snap-off blades does fine for rigid foam, extend the blade far enough to cut the depth/thickness needed - what most construction folks around here use, and worked fine doing daBus floor with very little mess, does nice curves and notches too

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics