A saw and a knife that cut rockwool insulation like a "laser"
"Amazon likes to show me things they think I'll like... and in this case, their algorithm worked.
These are Swedish-made Bahco Insulation knife and saw. For years I've used a cheap bread knife to cur Rockwool insulation. It works really well; it was the best thing that I had found. But I heard some guys talk about these, and took a stab at it, and they work really, really, really well. You can see my bread knife is no longer sitting here, it has been replaced, and I save it for peanut butter and jelly at lunchtime.
I want to say this knife is $19, something like that and the saw is in the $30 range, maybe forty bucks. So they're not cheap, but from the reviews I have read, guys say they last for a really long time. It's not like you buy them and throw them out.
I like that the knife has measurements on the blade—granted, it is in metric—but when I'm insulating an attic, I can hold it into a tight spot, get an idea of measurement, transfer it over to a batt and cut it. It cuts cleanly, quick.
The saw works really well for the rigid board; it cuts like a laser through that stuff. You end up with a factory split without piles of shredded insulation sitting all over the place."
—This tool tip was gathered from builder/remodeler Ben Bogie on the jobsite of Professional Remodeler's 2017 Model Remodel.