If it catches the plastic, it's still sharp. You can swap in a new box cutter blade if the edge is worn out, or you can sharpen your dull utility knife to give it more life. This is a sensible ...

Let’s face it: cutting foam with a knife, even a serrated plastic knife meant for the job, is a messy pain in the ass. This is as true for insulation board as it is for the ubiquitous expanded ...