Sawing styrofoam insulation

[Les Staley]

Anyone have occasion to saw white styrofoam blocks into 3-1/2" slabs for insulating a frame building.   Would the "sawdust" from this stuff ball up on the drive pulley and cause the band to over tighten?   I have a chance to get a large amount of solid styrofoam blocks, over run on a road building project.   Just wondering.    Thanks for any advice.  

[thecfarm]

No idea about the white stuff on a bandsaw.
But I cut a bunch of blue, 2 inch thick, with a plywood blade on a skil saw. The saw dust was very fine. Worked great.

[Larry]

I live on a COE lake. Some years ago they outlawed raw styrofoam billets for dock flotation, it had to be encapsulated. Lots of big blocks of the stuff was headed for the landfill. I sawed quite a bit to be used for outbuilding insulation. Made a big mess which I vacuumed up, but no problem sawing it.

[Resonator]

The cleanest way I've seen to cut styrofoam is with a electric hot wire cutter, as it melts it to cut it (no dust). Different types and sizes available online (I've even seen home built ones). Main caution you need good ventilation from the fumes created.

[Jeff]

[Ljohnsaw]

I have to ask, what in the world were they using blocks of Styrofoam for on a road project?

When I made my 6'x8' bathhouse for my cabin property, I wanted to insulate it well. I picked up a bunch of free foam boards and didn't want to make a mess sawing them up

I made a cutter with nichrome wire and a house dimmer switch. Could dial up the heat to whatever was necessary.

The wire is "live" so be sure not to touch it! Wonder if a GFCI would work on that circuit to provide protection?

[beenthere]

Insulate the road from freezing. Attempt to minimize frost upheaval. Thinking is it allows frost/freezing below the insulation, but prevents the thawing on warm, sunny days. i.e. keeps it frozen longer. 
Maybe someone discovered it didn't work or was leading to "garbage" under the road? 

[Les Staley]

Ljohnsaw, they were using the blocks under the bridge approach on State Hwy #3 crossing the St Joe river.  The water is at flood stage at times of heavy snow melt and still frozen ground.   Seems to work.  I cross that bridge multiple times Most days and the approaches are stable.  

[jaciausa]

What thickness or lengths are you receiving them? Depending on the thickness and width will tell how to saw. As others have said a hot knife is the only way if you have to resaw rip. I have cut many pieces of the correct 3-1/2 thickness with hand saw or a serrated long blade knife. It will snap correctly if you score deep enough.

[NE Woodburner]

I have to ask, what in the world were they using blocks of Styrofoam for on a road project?

I wouldn't say it's real common, at least in the northeast, but I have seen foam blocks used as lightweight fill. It will take a significant load if the load is spread out and good DOT gravel compacted in place is expensive, so in some cases it could be cost effective. I've seen it mostly used as a base backfilling near bridge abutments. Probably less horizontal pressure against the abutment than gravel, but that is a guess on my part.

[Nebraska]

I used my job site table saw it did melt a little on the blade and made a moderate mess. I was cutting 2 inch bead board for basement insulation.  Blade cleaned up with a little brushing. 

[WV Sawmiller]

   The only time I ever tried sawing it I used a portable 10" table saw and it melted and hardened right back into a sheet behind my blade.

   I have seen 1" thick (or thereabouts) sheets about 3'X4' on pallets of frozen food. It is used just inside the thick cardboard outer skin. I don't know a source or if it is sent back and reused.

[Hilltop366]

I've only used the circular saw and table saw, it worked well. May not be a issue but I think holding the foam in the mill may be the hardest part but worth a try.

If the mill does not work out perhaps it would work well combined with the hot wire using the mill up and down and travel to move the wire?

[DanielW]

That dust sticks to everything and is far from healthy to inhale. I like the idea of doing on a bandmil, but a hot knife is probably better for large thicknesses. Or investigate something like this (see link) - wavy-edge bands for your mill. Looks like these guys offer them in 1" and 1-1/4" widths and made to length. One blade would probably last the rest of your life (though I'd get two just in case one breaks).

https://industrialbandsaw.ca/wavy/blades.html

[Ljohnsaw]

Got an old nail strike blade? Make it a wavey blade!

[jpassardi]

I have cut quite a bit of extruded polystyrene (blue and pink board) on the table saw to insulate the Wife's She Shed.
The expanded polystyrene (white board) also cuts well on a table saw.

[SawyerTed]

I can see a bandsaw mill with a hot wire cutter mounted in the same planed  the blade would be in. 

There are 4' bow type cutters than could be a solution if mounted to the band mill.  That way setworks and power feed could be used AND NO SAWDUST.