Ok, got some time today so I tested those blades. They are the cats ***! I was concerned that they would not go through that felt paper like stuff on the outside. It goes through it like butter and leaves a very clean cut. And no mess at all. They are clearancing them at Menards now for 9.95 for a 3 pack.
Cutting polyiso insulation.
- Thread starter wantacoe
- Start date
NIS240SHU
Member
I do the same as Sherk and earlybirds. I sharpen the curved side of a 6” putty knife and it goes through foam easily with little mess. It works well because unlike a knife, its thickness is uniform throughout, so it doesn’t bind up.
dfiler2
Well-known member
I think you could mount the saw on the back side of sheet of plywood,run the blade up through a hole, then use a 2x4 and a couple of clamps for a fence and run them through pretty fast.
stokefire7
Well-known member
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- Oct 5, 2011
- Messages
- 616
Looks very similar to the stuff I got in Utah , fiberglass type cover , both sides. Table saw gives a good cut but have used everything mentioned above. Thickest I've got is 2.5". Firestone recommends not to breathe the dust, if you're concerned.
zeekh
Well-known member
Do we have any updates on cutting this? Right now I'm using a table saw to cut 3"? polyiso and the dust is wicked bad. Dust masks are hard find right now in stores. I'm eye balling the bosch blades but they'll take a week to get here. The circular saw blade mentioned above looked good but the 10" blade for a table saw got crappy reveiws. Right now my game plan is to make a hood to go over the blade with vacuum hoses attached. I have one connected to the saw dust output but it doesn't help much. Any input would be appreciated.
ETA: I have about 80 sheets to cut.
ETA: I have about 80 sheets to cut.
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rustyjames
Well-known member
I always cut it outside with a straightedge and a handsaw.
dutchgray
Well-known member
Extract the table saw with a hood will help but I would still want a mask, the dust is really fine and always seems to escape no matter how much extraction you have. I have cut hundreds of sheets on a table saw, have literally spent entire days ripping sheets to fill between studs. Its never a fun job.
Could you also rig up a leaf blower to blow some of the dust away ?
Leaflessshadetree
Well-known member
I set my table saw up just inside the garage door and put a big fan behind be blowing out. Worked good as long as the wind wasn't blowing in.
masterofall
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- Apr 6, 2022
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I have developed a unique way to do my rim joists when framing using inch and a half poly ISO. For cutting I use a wallboarders buddy drywall cutter and simply score both sides then snap it just like wall board. The cut is clean and there is no waste to clean up.
We set the TJI rim joist back an inch and a half, place 2X4 squash blocks in line with the stud layout, place rock wool in the web space and then squeeze the poly ISO between the squash blocks. The rim area then gets covered with sheeting material nailed to the squash blocks.
It is one part of a smart framing technique developed to reduce thermal bridging. The energy savings are noticeable.
We set the TJI rim joist back an inch and a half, place 2X4 squash blocks in line with the stud layout, place rock wool in the web space and then squeeze the poly ISO between the squash blocks. The rim area then gets covered with sheeting material nailed to the squash blocks.
It is one part of a smart framing technique developed to reduce thermal bridging. The energy savings are noticeable.
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nmk_61802
Well-known member
I used either a table saw or a retractable snap blade utility knife that I could keep the blade extended out on. This was for 2" foam, 3.5" may make the blade wander slightly if you need a perfect cut TS is the best way.
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Chris705
Well-known member
Not sure of the intended use for the foam described above….”tar-like paper” it sounds like polyiscosanurate or what is commonly used on commercial roofs. This can be used in walls & roofs but should never be used underground for slab insulation. It will absorb water. Hopefully under slab use is not the intent.
man I hate it when I fail to read OP date….
masterofall
New member
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- Apr 6, 2022
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When we are cutting the poly ISO it is out side on a jobsite so the drywall cutter avoids setting up a tablesaw and all the waste that needs to get cleaned up after.
A word of advice if your ever cutting XPS styrofoam. Do not use a table saw. We had an incident a few years back in town where someone was cutting a lot of it. All the particles left over from the cutting were in the catch base of the table saw and ended up catching fire. I think there is some type of exothermic reaction the occours after cutting, possibly from the gas that is released.
Another note, I was at a lecture another time pesented by an architect who used too much thickness of spray foam on a energy efficient house project. The foam did not set up properly and again an exothermic reaction caused a fire that ended up burning the house down