circular saw to cut foamboard?

[Dave Maxwell]

Anybody use a circular saw to cut foamboard. If so what blade. Fine tooth plywood?

 

[venturesomerite]

I just use a t square and a box cutter to score it.

 

[Dave Maxwell]

The two inch stuff? Will try
Thanks

 

[shoturtle]

I would guess a metal blade without the big notches. Think the wood blades have the with their large notches on the teeth would cause a rough cut. I normally use a jigsaw for foam board.

 

[Gregishome]

Take one of Momma's 4-6 inch long kitchen butcher knives and break/cut it off to where it has a square end on it and resharpen it. Keep a sharpening stone handy to keep it sharp between cuts and just bear down hard while running it up against a straight edge to make good straight cuts. Lay the foam on a piece of old plywood for a cutting board.

 

[Dave Maxwell]

Even thought about an electric knife

 

[Gregishome]

The pros that install Drivit use an electric "hot" wire knife to cut their foam board.

 

[Falcon67]

Score with a knife and snap like Sheetrock.

 

[aar_man]

I used 2" blue board under my slab for insulation and cut it with my cordless Dewalt and the utility saw blade they include with the saw.
It also worked great for the 45 degree cut I put on the vertical perimeter insulation to set my floor grade.

 

[Gary S]

Score with a knife and snap like Sheetrock.

Yep, that is what I do. It is so simple to do this way, why make it any harder?

 

[Ken Greene]

good old fashion wood hand saw is all we use when installing foam to houses.
fast cuts, quiet. less messy.

 

[Dave Maxwell]

Bought a fine tooth saw. Working good so far. Going to try baby powder for the friction binding

 

[matouse3]

I used a table saw with a fine tooth blade. Used it to strip it and then put a 45 on the edge pieces. Worked great but make sure you hook up a vac to the saw as it creates a lot of bits and pieces.

 

[casetractorfarmer]

Works awsome only thing is it makes one hell of a mess

 

[GMBracing]

just used one of those cheap razor knifes, the one that the blade extends out an you can snap off to keep sharp. used straight edge and extended the blade and cut the 2" board clean. get a couple because you will dull them.

 

[demographic]

I usually just use a normal hardpoint handsaw thats past its best, cuts just fine and I don't like wasting a good new handsaw on it.

 

[Dave Maxwell]

Got a little fine tooth handsaw from home depot that is working pretty good so far. Cuts clean. Blade grabs sides because of friction

 

[jlckmj]

My battery operated saws-all with about a 6 inch blade worked great for cutting the 2 inch board.

Jim

 

[Big-Foot]

I had a couple hundred feet of 2" pink to cut and used a circular to do it. Go slow or you will have a mess as the sawblade will get hot enough to melt the foam. While on the surface, that might not seem like a bad thing, blieve me when i tell you that it will make a gooey mess of your saw.

 

[rburke65]

Thoughts on using a hot wire set up?

 

[steel 35]

Thoughts on using a hot wire set up?

It really stinks! but works on thick stuff and a wire wheel on a grinder does some nice shaping but its messy....

 

[kellymc]

We used a guitar string set up on a c-shaped steel section with a guitar tuner to tension the string. We mounted the steel-c on a piece of ply and used a 2x4 to control the width of the cut, just push the foam through the tensioned wire and it cuts it like butter. No heat, no mess

 

[Highbeam]

I have cut lots with a circular saw. Go slow so that the blade stays cool or else the boogers of melted foam will harden onto your blade and then the next cuts are wider and uglier. I cut lots of 45 degree bevels with the saw too. Looks good with the high speed blade. Use whatever framing blade was in the saw, teeth pointing the normal direction.

I've also cut lots with a sawzall and demo blade. The sawzall doesn't melt the foam but cuts are less precise. This is good for cutting the bevel into the top of the installed perimeter foam.

 

[NUTTSGT]

When I cut some 1 1/2" white styrofoam I used a steak knife, maybe a bit of WD40 on the blade here or there. I'm not sure how it will work with pink foam board though.

 

[rsa]

It was too expensive, but I used a beveled, toothless blade on my table saw. They're advertised for cutting cotton insulation. On two-inch foam, I would set the depth to a little over an inch and cut twice, flipping the foam. Not the right choice is you need cut edges as perfect as the factory edges, but was close enough for me. No mess and much less kickback. The one I used was only eight inches in diameter.

I haven't used one yet, but next project, I might try an Insul-Knife. Reviews say you need to sharpen it often.

 

[kert]

Used a table saw to cut mine. The few crosscuts I did with a handsaw.

I disagree with the slower is better mantra. As anybody who has worked with cherry will tell you if you don't maintain a good feed rate, you'll get burn marks. The key is to move fast enough so the blade doesn't have time to transfer heat.

 

[ishiboo]

I just use a t square and a box cutter to score it.

I cut a bunch of foam board a year ago. I bought the HF hot knife blade, had a pruner blade in my recip saw.

Only way to go is to score and snap unless you need a VERY accurate edge. ZERO mess and it's SO fast. The use of any toothed blade puts staticy foam everywhere.

It will take a couple cuts to figure out the best angle for the box cutter. You can also spray silicon on the blade prior to a cut, which makes it go easier.

 

[weston]

I use a Fein oscillating multi-tool with the wide blade. It works like a champ on up to about 2" foam thickness. It's fast, generates minimal dust due to the narrow kerf, and makes clean, accurate cuts. Excels at plunge cuts and final shaping.

 

[BFBOB]

Depends on how much you need to cut and how accurate the cuts must be. I've used most of these methods except the Fein and the cold wire (gotta try that!!) For me, table saw is best for accuracy and appearance, if the foam will be visible. Messy, but vacuum hookup catches most of it. I made my own hot wire cutter from a foot of 18ga nichrome wire from an old space heater, powered by a 10A battery charger. Crude, wooden construction, overarm like a bench jigsaw, but works great for curved cuts, intricate shapes. For rectangles, I like the table saw.

 

[Relie]

just used one of those cheap razor knifes, the one that the blade extends out an you can snap off to keep sharp. used straight edge and extended the blade and cut the 2" board clean. get a couple because you will dull them.

This is how I did mine and you will dull them. Be patient, I did my 24x40 with foam board. (By the way, it is the best insulator I've used to date.)