Cutting Rigid Foam Board the Easy Way
 

We have a stack of 4 inch rigid foam board to use in the attic. This looks like a lot cleaner method of cutting rigid foam insulation board than the messy table saw or kitchen knife..........
I suppose if you didn't have a lot then you could do it like they did it on Fine Homebuilding http://www.finehomebuilding.com/how-...nsulation.aspx

But I like this way best....
Video

That is pretty cool. Its a nice idea. I don't think I'd ever cut enough foam to make buying that tool worth while though.

When I cut a BUNCH of foam for my solar hot water lines between the house and the solar panel rack, I cut them with a pocket knife... It took a while, but it wasn't messy and I cut it all inside my house.

http://ecorenovator.org/forum/attach...-house-018-jpg

this works for me.
$0.75 Handheld Hot-Wire Foam Cutter - YouTube

To cut larger sections or swaths, I rig up a stationary vertical wire section to some jumper cables on the side of a bench.

Thanks Guys. I really like the wire cutting tool, but I ended up sharpening the edge of a 4.5" putty knife and cut all of them in about 30 minutes. Now for the fun part of installing them in the attic!

Cutting foam with heat produces pretty nasty gasses so I think the blade idea is way better.

I've been using a small drywall keyhole type saw when cutting against the grain of 2" XPS but when I'm cutting with the grain I'd score each side with a box cutter and then snap it. The snap is clean but if I try to use the box cutter against the grain it breaks up the foam and doesn't cut well so I use a keyhole saw for that.

I wish I knew the putty knife trick because that sounds slick. I ended up making a big mess in the basement when cutting my sill plate foam plugs but it wasn't too big of a deal with a shop vac on a concrete floor.

On second thought I'm curious if buying one of the bigger style pizza cutters(large enough to go all the way through the foam you are cutting, not the tiny ones) and sharpening a good knife edge to it would be a good way to do this.

Wow, I used a circular saw. Made a fair mess and really gummed up the saw. That was a real pain to clean.

OTOH, It did a nice job. Since I was cutting WAY TO FAR from the sides or ends to use the yardsale flashlight model, it seemed like the thing to do at the time. :eek:

IYeah, just like a supermassive olfa tool. Just make sure to go fast enough and with lots of downward pressure.

Another easy way is the mighty Rotozip. A shopvac hose placed close to the messy end helps grab the chips and.dust.before they fly away.

I had a load of 2" EPS to cut for my kitchen floor, so I set up my contractor-type table saw in the back yard and did the deed all at once.

I had a passive debris catcher bag thingie (old tee-shirt with the sleeves & neck sewn shut) hanging on the out put of the saw, that caught some of the kerf-dust, and what little escaped the catcher bag has now become part of nature.

Overall, it worked just fine... fast and accurate and not nearly the debris problem I had imagined.

-AC

Looks like a pizza slicer, but works really well.