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easiest way to cut Styrofoam

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ive done some playing around with some styrofoam on a small scale, its worked ok,  my question is whats the easiest way to cut an shape larger pices??thanks

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If it’s the extruded polystryene foam insulation (pink or blue), then a hot knife or hot wire works well. You can get a length of nichrome wire and some fittings to hold the ends and hook it to a transformer to slice big stuff up if you make a jig to hold it sort of like a bandsaw setup. They have just hot knives as well.





Hotwire cutting does not work so well on compress beaded styrofoam and I generally avoid it as messier to work with and does not shape as well as the extruded polystryene.


other options are plain old finer tooth hand saw or hack saw or a circular saw or table saw with a plywood blade on them. But this is messy and the resulting styrodust statically clings or everything and has sharp little edges which can irritate your skin, especially when it gets under clothing.


dollar store serrated knives (bread knives) and larger serration steak knives also cut it well.


there are a few topics on the forums on this I’ll see if I can find them.





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What are the issues with the beaded whitestuff?  I am pretty sure lots of the R/C glider wing cores I have bought have been white beaded foam and are cut using a hot wire.  


Not disagreeing with you -- just asking what the issues are due to my remembered previous experiences buying such things.  I could be totally off in my remembrances and it was a white colored extruded foam, but typically if they were the more dense stiffer cores they were blue or pink.

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The beaded polystryene does seem to come in a spectrum of densities. I’ve just had the cheap packing stuff melt very easily and leave a much more rough edge. Also cheap stuff when using a rasp or even serrated knife will rip out balls instead of cutting or filing them off. Extruded stuff just behaves much more like manipulating a very soft wood more and I’ve had much better results with it.


i know the beaded foam you are referring to in gliders and it’s a lot denser and better fused than the packing stuff is. Extruded polystyrene is much stiffer (and probably why not used in glider wings you may want to flex some) and why I like it for scenery as it can actually be quite structural if needed, but still lightweight.





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The stiffer better wing cores actually are usually pink or blue.  But I had a lot with white foam as well.


Thanks for the response.


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Welcome, yeah the beaded stuff is just so varied. Some is so fused it breaks just like the extruded stuff and some just explodes. All the stuff I ever have hanging around of the beaded stuff (and I expect most folks) is almost always pretty cheap stuff which I’ve just had rotten luck with playing with for scenery I just avoid it. I only keep it around to use for packing boxes. Pink and blue extruded insulation board is just so available at big box stores even in 2’x2’ chunks that it’s always my goto.



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