worse than homasote

Razor knife is best for foam and homasote. My opinion.

Yep. Even a hot knife if you have one.

Dennis

I was trying to make bridge abutment piers  and I tried hot knife straight not so much. and a knife seems to create a pulled area at top with mini tears as I go.

I bought a tippi guess I should have gotten the power part as it gets to hot holding power switch on as is and it literally melted the wire tip!!

but thanks for the ideas like I said I'd rather cleanup the dust from homasote than the foam, can you hear me chuckling.

StPaul, your right on the power controller, and too much heat.

Our club opted for a reostat controller, and did some experiments, so I guess to say, it's kinda like "Baby Bear's Porrage" now ,cuts quick, with a minimal of smoke-n-smell!................And No More Dust!

A saber saw will make less mess than a table saw. Try different blades to see what works best on the particular material. 

DMASSO posted:

Razor knife is best for foam and homasote. My opinion.

Ditto.

Try this next time.... Knife Edge Jig Saw Razor Blade

Hello STPAUL    I use my table saw to cut blue foam board, because I also make walls, portals and abutments that need a clean square cut with a smooth finish, personally I think Homasote is by far worse than Blue styrofoam. now that white beaded foam board, that's a mess. maybe try a different blade, smaller teeth? I think I use a plywood blade and always carbide if that matters.

Clem

I like the knife edge jig saw unfortunately  the big box stores around me again are useless.  but can get from amazon ironic!

thanks for the alternative ideas will give the jig saw one a whirl.

Southwest Hiawatha posted:

A saber saw will make less mess than a table saw. Try different blades to see what works best on the particular material. 

Exactly!.....   And that's what I use to cut all my construction foams....blue/pink open-cell, white Styrofoam closed-cell.

But I use a knife blade to do so....NO teeth whatsoever.

The old blade I've had kicking around in my motley blade collection is a simple 4" straight-edged blade.  But today they make more sophisticated variations for cutting soft materials.  Like this 6" offering...

Sabre Saw Knife Blade

I once used an old electric carving knife with a scalloped-edge knife to cut a bunch of beaded Styrofoam.  It cut cleanly, minimal foam mess....OK for the job-of-the-moment.  But the same sort of blade in a sabre saw gave me much better control for cutting large sheets.  It's been even more useful for cutting curved patterns in sheet foam for scenery work, etc..

I believe the home improvement stores have these sorts of blades available.  More certainly a well-stocked hardware store.   Found quite a few brands/options on-line, too.

ANY blade with teeth....no matter how fine (high tpi number) the teeth or diamond-grit edge...will create a lot of static dust.  A clean cutting knife edge.....very, very little dust.  AND NO FUMES such as you get from a hot wire/knife cutter.

FWIW, always...

KD

I also strongly suggest a knife for straight cuts, and a knife-edge blade (jigsaw) for curved and angle cuts. I have used them for cutting QuietBrace, Asphalt board, and Homasote. No mess at all, no clean up, no kerf.

However, I am not sure whether the jig saw with a knife-edge blade would cause some melting on foam board.

Alex

When my son was building with foam board, we purchased an inexpensive set of kitchen knives at our local supermarket and he used those.
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Try a variable speed Multi-Tool, like a Fein, Bosch, etc.  You will be surprised at the variety of blades and what one of these tools will do.  It is not a Skill Saw in nature but a precision instrument for performing a host of unusual projects.  Made our kitchen & bath projects easy from removal to installation in those impossible places to cut.  

Check out Jon Eakes for more information:  www.joneakes.com   By the way the proper name is "oscillating tool".  I got the vacuum pick up attachment for both tools.  They work.  You will be surprised what you can do with one when you remember to use it!  The Fein will outlast most of us with sensible use.

Richard Snipes

For my Saber saw (jig saw) I grind my own knife blades from a dull toothed blade. 

I tried a knife blade in the saber saw, but the only one I had was too flexible and wouldn't keep a straight cut. If you can find a knife blade for a saber saw that is really stiff, I would agree that is the best choice. I forget what I wound up using but it didn't produce too much dust.

I started out using the knife blade in the sabre saw, but wore these out too fast.  Figured out that using my band saw worked great and I could also put the bevel in for road bed using it w/o much of a mess; nice polished edge and minimal dust and debris.  If the piece was large or awkward, just cutting with a hand saw worked fine to get it to be manageable.

Just use a regular hand saw for foam.......