I'm considering modifying a foam glider into an RC plane, but one of the problems I'm worried about is that all the electronics will be sitting rather exposed on top of the fuselage(I think that's the right term for the long skinny tube part). So I figured 'oh I'll just cut out some holes and set the stuff in there' but I don't know how I would cut the channels and holes for wires and hardware and leave a floor for it to sit on. If needed I can cut all the way through, chop off the top bit or so, and then duct tape the bottom part back into the plane to make an indent. But this method still needs a knife or something to go all the way through the foam, and I know that's not gonna happen without seriously mangling the plane and wasting foam. I looked into hot wire cutters, but for that I would have to cut from the outside of the plane and that would weaken the plane overall.

How can I cut through up to 4 inches of foam while minimizing the amount that turns into that annoying fluffy snow stuff that gets everywhere?

  • 1
    Can you add a photo of the glider, and/or a link to a product listing for the glider (if it's a commercially available product) or the foam you made it out of (if it's homemade)?
    – csk
    Oct 6, 2020 at 22:53
  • @csk, it will be something along the lines of this although I might buy a different version locally but it's the same general thing. Oct 6, 2020 at 23:18

1 Answer 1


The "aircraft" you reference is made of expanded polystyrene foam, also known as Styrofoam™. It is sensitive to heat to the point that there are high-temperature-based tools to address your goal.

Rather than spend a bunch on specialized tools, you can use a soldering iron set just low enough to control the level of melt generated. If you have a single temperature tool, speed becomes the control.

Another approach that I've used is a bit more time consuming, but allows for much greater detail work. A butane lighter or steady heat source is used to bring a long sewing needle up to temperature. Obviously, pliers or similar must be used as a handle. You can drive the needle to the required depth at the corners of your recess, "draw" a cut-out outline and then use a soldering iron to eat away at the middle of the mass.

If you're handy with other tools, hammer the point of a nail to a flat blade and use that as your tool. You can hammer a spoon shape into the nail to get a smoothing tool.

The possibilities are limited only by your imagination and available resources in the tool department.

  • 2
    A heated knife is also a very useful tool. Old kitchen knives tend to be better than craft knives for this. Personally I wouldn't use either of my soldering irons because I want to keep them clean for soldering and the fumes from styrofoam at full iron temperature are unpleasant at best, toxic at worst. Good ventilation is essential
    – Chris H
    Oct 7, 2020 at 10:58

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