Cutting polysio foam insulation with a track saw

[Bill Dufour]

Wondering if anyone has tried using a tracksaw to cut polyisocyanurate insulation. Did the chips clog up the dust port. Did the track slip on the foil facing? Seems like such a plan may be easier then using the tablesaw.
I do not own a tracksaw so I will use a skilsaw and a 2x4. It will be hard to clamp. Probably need wood on both sides so as not to crush the foam and allow the guide board to move around.
Bill D

[Lee Schierer]

I do not own a track saw. I suspect that the first cut will probably work okay, but after that the little bits of foam dust may start to cling to the track and make it tend to slide on the surface. I've had good luck cutting foam on my table saw using an older thin kerf ripping blade. You will get plastic melting onto the sides of the blade so don't use your best blades.

[Zachary Hoyt]

I would try a utility knife if it's 1" or 1.5", or a hand saw might work too if it's thicker. When I was a kid we lived in a passive solar house and had inside shutters made of that material that we put in the windows at night in the winter to keep the heat in. I remember my parents using a cheap hand crosscut saw to cut it, and the saw moved through the panel very fast and easily, and without any melting or other issues. I think they would back cut the last inch or two before starting the main cut so as to avoid chipping at the corner when the cut was completed.

[Mike Stelts]

I've cut quite a bit with a circular saw and Japanese saws. It cuts so easily that there's no melting.

[Keegan Shields]

If possible, the pink stuff is much nicer to work with. I use the pink ridged foam under whatever I’m cutting with my tracksaw to prevent cutting my workbench. Cuts it cleanly, no clogging issues.

[Rich Engelhardt]

I use a serrated blade steak knife that Outback somehow managed to sneak into my car one time when I ate there.
(I keep it in the drawer right next to the crab fork from Red Lobster that somehow managed to follow me home.)

[Edward Weber]

I know where I live, contractors use an abrasive metal cutting blade for vinyl. It may work the same for foam, I don't know for sure but it might be worth a try.

[Paul Haus]

If that's the foam insulation board, don't rule out an electric carving knife. I've cut some boards before that way and it worked out just fine.

[Paul F Franklin]

I've cut lots of rigid foam of all types with my tracksaw. Clean cuts and since I use a vacuum with it, very little foam dust escapes. Doesn't clog the hose or build up on the blade. I never bother to clamp the track but if for some reason you needed a cut to be perfect, you certainly could. If you're just using a 2x as a guide, then you will want to clamp it. If you use quick clamps, they won't dent the bottom of the foam unless you really overdo it.

[Jared Sankovich]

A track saw works great for polyiso. It's all I use to cut the stuff now.

461920
461921

[Jim Dwight]

I use my track saw with an old blade to cut drywall. Not sure I've ever tried it on foam board but I'm not surprised others report favorable results. It's a versatile tool.

[scott lipscomb]

I've always cut it with a sharp knife and straight edge. It cuts really easily.

[johnny means]

I've always cut it with a sharp knife and straight edge. It cuts really easily.

Yeah, I was thinking the same thing. Well for me it's a fillet knife. A track saw seems like a lot of unnecessary effort, though I have used a table saw when cutting dozens of sheets in the shop.

[Jim Becker]

I think there's merit in using a track or guided saw for cutting a quantity of this material and I'd consider it if I was going to be in that situation. Yes, a table saw can also be used, but a lot of times when folks are using a quantity of the foam insulation, it's more of an "on-site'" thing before the table saw moves in I would think. But that's an assumption that isn't necessarily valid. For a small amount...I'd also pull out a knife of some sort...even an old, cheap steak knife. (I actually have one of those in my tool chest)

[Bill Dufour]

People are right this is to insulate the roof of the garage before the saw is in the way. I would like nice clean cuts since it will be seen from below. Just was not sure if polyiso was as easy to cut as styrofoam. I understand a hot knife will not do much unlike styrofoam. I suppose I could use aluminum tape on the edges to hide everything.
Bill D

[Jim Becker]

Whatever method you choose, accuracy will be a good thing, not just for visual appeal, but also because it cuts down the amount of sealing you'll need to do along the edges of the material. Straight cuts and a snug fit are a good thing.

[Osvaldo Cristo]

If you are looking for a saw to cut a such insulation, consider a guided jigsaw with appropriate blade.

Bosch makes blade specific for it but I guess it can be done by other manufacturers also. These blades are toothless and have some kind of waved knife like cut similar to traditional bread knife.

[Wayne Cannon]

I switched to a thin putty knife sharpened along its side, after trying a serrated knife and twin-blade electric knife (which is the cat's meow for soft foam cushions, BTW). The putty knife's length makes cutting straight lines especially easy. Cuts are clean and beautiful. I don't remember where I saw this tip, but it works great.

[Myles Moran]

I switched to a thin putty knife sharpened along its side, after trying a serrated knife and twin-blade electric knife (which is the cat's meow for soft foam cushions, BTW). The putty knife's length makes cutting straight lines especially easy. Cuts are clean and beautiful. I don't remember where I saw this tip, but it works great.

I saw a similar tip as well. I just use a big knife since my use was limited to about 3 sheets of it. If I had more I would have sharpened up a putty knife. I tried using my circular saw, but found the dust it made stuck everywhere and was a huge pain to clean up.

[Bill Dufour]

Used a big kitchen knife and it went well today. After I cut it I shaved it back a few degrees so it fit in better here and there. Still made a big mess. Not as messy as styrofoam. I cut once at about 60 degrees to the travel maybe one inch deep then came back and went all the way through 2" deep pushing and rocking the blade on both ends.
Bill D

[Rich Engelhardt]

Mafell makes this little gem of a track saw for cutting insulation.
https://www.timberwolftools.com/mafell-dss-300cc-insulation-saw

[Alan Lightstone]

Mafell makes this little gem of a track saw for cutting insulation.
https://www.timberwolftools.com/mafell-dss-300cc-insulation-saw

IDK. $3800 saw vs pilfered knife. That's a tough call.

[Rich Engelhardt]

$3800 saw That's the cheap one! :O
The upgraded one is over 8 grand. It comes with the dust collector & table.

[Rick Potter]

Installers that I have seen all seem to wear a knife. Bread knife works great for me.