Is there a way to cleanly cut Styrofoam?

Question

My roommate is a bit of a pack rat and has several old TV and computer monitor boxes with Styrofoam supports.

I am thinking of cutting the Styrofoam into little "bricks" and building a small house out of it.

Is there a trick or special tool to make clean cuts without making a mess of little Styrofoam bits everywhere?

Just a quick note: styrofoam bricks are often a problem to build with. Make sure you use the right adhesive or it will fall apart with time. Some people prefer cutting with hot wire, then sticking the still tacky blocks together an letting it set,but this requires lots of practice to get straight. — Gwyn, Mar 19 '21 at 10:45

score 16 · Accepted Answer · edited Oct 26 '22 at 21:51

16

Is there a trick or special tool to make clean cuts without making a mess of little Styrofoam bits everywhere?

Yes, it's called "hot-wire (foam) cutter" which can be bought starting at prices of about $20, or you can also make one yourself.

foam cutter

The hot wire melts the Styrofoam, releasing toxic fumes (styrene), so it's best to use it in a well-aerated room or outside. (See e.g. this link for more safety advice.)

It will work on Styrofoam, but probably not very well on soft foams.

edited Oct 26 '22 at 21:51

fixer1234

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answered Apr 26 '16 at 22:24

Earthliŋ

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Is there anything we need to know about how to use this properly and safely? Does it work the same on all types of foam? – Apr 27 '16 at 23:23
The YouTube video is gone. – ken Mar 18 '21 at 22:47

score 1 · Answer 2 · edited Oct 26 '22 at 14:11

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An X-Acto knife is probably going to be your best bet for the least cleanup of loose Styrofoam. Cut firmly but not so deep as to tear the Styrofoam. Basically just the tip each pass and make multiple passes. It will be slow and tedious, but if you do it right, it won't be messy.

A faster method is to use a scroll saw with a vacuum attachment. This will create more pieces of Styrofoam but most of them should end up in the vacuum receptacle, reducing the amount of clean up. This will be a lot faster at the cost of a bit more clean up.

edited Oct 26 '22 at 14:11

Allison C

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answered Apr 26 '16 at 21:15

Chad

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Scroll saw I think is a terrible choice for this since it would be moving up and down. Foam is light enough that the blade would be picking it up. Not to mention that cutting the foam could make it move around and expand just slightly as it is cut so that the blade would rip it more that cut it. This can largely depend on your foam choice as there are OODLES. Craft knife would be good as long as the blade is thicker that the work piece. – Matt Apr 26 '16 at 21:27
@Matt It is what I have used in the past It moves so fast and the blade is small enough that the "sawdust" pieces are actually very small. I have used it on several different types of styrofoam. The only type I would be leary of trying would be the spongy type that never really hardens. – Chad Apr 26 '16 at 21:35
Cant argue with experience then. – Matt Apr 26 '16 at 21:37
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Why don't you use a hot-wire cutter? – New Alexandria Apr 26 '16 at 23:06
@NewAlexandria Well I do not have one first. I suspect that would leave the styrofoam blocks with a foul smell. Maybe I am wrong and maybe that wont matter. Not really sure. – Chad Apr 27 '16 at 02:32
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Styrofoam releases VOCs, so the odor doesn't stay around for long. – New Alexandria Apr 27 '16 at 03:33

score 0 · Answer 3 · answered Oct 21 '19 at 18:42

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They call them hot knives. Specifically designed for making clean cuts through styrofoam.

answered Oct 21 '19 at 18:42

kkulpa

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Is there anything we need to know about how to use this properly and safely? Does it work the same on all types of foam? More details could help expand this answer to be more useful! – Erica Oct 22 '19 at 09:15
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Hot knives is a little vague. From what I have seen styrofoam cutters actually use a wire, not really a knife at all. – rebusB Oct 22 '19 at 19:41

score -2 · Answer 4 · edited Dec 08 '18 at 19:43

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Just take a lighter and slightly burn the area that was broken in half or cut and it will no longer shed. Be careful as it will burn and may drip on your skin.

edited Dec 08 '18 at 19:43

inkista

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answered Dec 06 '18 at 13:18

M.T.Ford

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This is useful, but not much of a help for making clean cuts in the first place. – Erica Dec 10 '18 at 00:23

Is there a way to cleanly cut Styrofoam?

4 Answers4