Cutting foam for cases
This is not something I need right now but probably will again sometime... thought I'd pass it along.
I think most of us have struggled at one time or another with cutting foam for camera cases, etc.... or at least cutting it well. I've forgone things like attempts with the hotknives you can buy at Harbor Freight, etc., and the last few times I have needed I have used an electric carving knife (that I actually bought at a thrift store for just a couple of bucks). It works pretty well. But far from perfectly.
I do a big Halloween blow-out every year, and a few minutes ago I was browsing the website of the company where I buy things like actuators and prop motors for my animatronics, a place called Fright Props. I saw something that I'd never noticed there before, that being a whole bunch of specialty foam carving and cutting tools...
They might have some things I'll try the next time I have to outfit a case, and just thought I'd pass it along.
Fantastic Plastic Entertainment, Inc.
You'll get better results using the "bow" or "scroll saw" style of hot wire, than the long, thin one that looks like a very skinny soldering iron... those are very, very delicate. While they will work for something like trimming the foam in an instrument case, you have to be careful and patient in the speed and amount of force you apply on it as they bend and break easily. They're made for styling the very light "floral" foams. The large knife with the blue handle is the same as the one from harbor Freight, which is a high-heat item used for cutting linoleum tiles. On regular foams it tends to just melt everything before you can make a serious cut.
I do a lot of foam cutting in my model airplane hobby, is where my experience comes from. I reserve an old pencil iron for making holes in foam, then I use a bow style to complete inside cutting in a scroll-saw style.
Nichrome wire is the best choice, but you can get results using steel fishing leader or even steel guitar string. An old model train transformer/speed controller rheostat regulates the power. You can make the "bow" out of anything non-conductive. The key is to keep the wire in tension once it's hot: a sagging wire makes sloppy cuts, so add a tensioning spring to the rig somewhere to keep the wire tight, or make the bow itself impose the tension.