"Best way to cut foam core?" Topic

Seems every time I try to cut Foam Core, the paper catches on the blade and rips instead of cutting. Any tips on tools, techniques, etc? Thanks Much

Xin

I use a laser. It is the best way I have found.

you have to use a brand new blade regularly, as a blunt blade just tears the coating. foamcore blunts blade more quickly than you'd expect.

regards

jim

I use one of those hobby knives with the break off edges. Foam core dulls blades fast and with the break off tips you always have a sharp tipped blade ready and the X-acto one is nice and slim for those tight corners.

They have tools made specifically for cutting foamcore

dickblick.com/zz574/44

If you are going to use an xacto or similar blade, you'll need to change the blade really frequently (like every 5-10 cuts) or else you end up tearing the paper ;)

You can also make a quick light cut to cut through the paper, again to cut through the foam and one more for the paper on the other side.

Lastly, gatorboard is a wonderful alternative for foamcore as its very lightweight, durable and won't warp – plus, with a sharp knife it cuts really well.

Besides using a sharp knife, as mentioned, use shallow cuts. Do not try to cut through entire piece with one slice. Break the paper surface on one side with first slice, then cut the foam, then slice again to get the bottom paper layer. Use the sharpest knife to do the paper, but you can use a more used one on the foam. Cut the foam with a sawing motion.

That Logan cutter looks nice, but it costs $20. USD It would solve my problem of never getting a square cut. My blades always angle just a bit when cutting, having the top longer or shorter than the bottom of the foam. This has made working with foam core a real PITA for me. Cutting window openings is also a nightmare.

Unfortunately the advice above is probably your best solution – in my experience you go to Michaels and purchase the 50 pack of #10 Xacto blades and start cutting. When you are done, you have a couple of blades left over – depending on the size of the project.

Never try to cut it in one go.

If you cut slowly and steadily, using 3 cuts per sheet (top layer, then foam, then bottom layer) then a new blade (or snap-off blade section) can last you a fair while.

If the foam starts tearing in the middle then you have to change blade.

My blades always angle just a bit when cutting, having the top longer or shorter than the bottom of the foam

This is easy to remedy for free:

Cut along a steel ruler with only one eye open – have that eye lined up directly above the cutting line and cut toward you – you should be able to produce a perfect cut this way. (indeed you can cut a virtually straight edge without even using a ruler using this methodology)

Cutting window openings is also a nightmare.

Mark out the window on the foamboard, then cut the window smaller than you need it – then sand it down using a "sanding stick" (or glue some 400-600 grit wet'n'dry to a piece of plywood) sand it down to the exact size you want (the marks you put on originally).

Doesn't take very much longer and is as precise as you need it to be, plus you get nice sharp 90degree corners.

Darn link didn't work…

Allen

Back when I was working theater scenery crew, we cut Foamcore with a saber saw. You can get a knife blade (no teeth) for it. Works fine and is reasonably fast, but may not be precise enough for what you're doing. Also, you'd have to dress the edges, since the saw leaves them a little rough.

X-acto makes a foam board cutter that you can pick up at Wal-Mart or similar big box store for about $9. USD It allows you to cut at 90 or 45 degrees, plus it holds two blades so you could cut long strips if you needed to.

Thanks guys. Woot, I get to go buy more tools.

My fine tooth table band saw works well with foam core.

The logan cutter works great. With a fresh blade the cut will come out perfectly.

I have had good luck cutting FC board with razor blades. Not so common in the stores any more but if you can find some, break in half, put tape on non sharp side to hold better and slice away. Also, one side blades, used for paint scraping, work well

@ Pictors studio…

What laser setting do you use because when I've cut through with a laser the foam melts in the middle. What laser, Trotec or Universal?

cheers

For windows, puncture the corners first with a drawing pin. This makes it a lot easier to cut and less stressful on the blade.

Sorry for the thread necro… haven't had time for the hobby lately.

Just keep a whetstone out when you're cutting foam. A few quick passes against the stone will restore the edge. The high carbon steel in an X-Acto blade sharpens very well. (Make sure you know how to sharpen knives though…)