Planing rigid foam

[Art Kelly]

I just got a Weekly eTip that said to use a power planer to trim rigid foam. Interesting idea, but the last time (a LONG time ago) I used a plane to trim some plastic, I regretted it for the two hours it took me to reshape and resharpen my plane iron. Some plastics, while they are friable, are very hard.

Anyone have any experience?

Art

[Eric Gustafson]

The RC airplane folk make wings with a hot wire foam cutter. They are cheap to make and with jigs to guide the wire you get repeatable results and a smooth finish.

http://www.instructables.com/id/Hot-wire-foam-cutter/



I just got a Weekly eTip that said to use a power planer to trim rigid foam. Interesting idea, but the last time (a LONG time ago) I used a plane to trim some plastic, I regretted it for the two hours it took me to reshape and resharpen my plane iron. Some plastics, while they are friable, are very hard.

Anyone have any experience?

Art

[Ronald Kellison]

I suspect that a Surform or a microplane rasp would do the job easily.

Ron

[Myk Rian]

They use power planers to make surfboards. You have to move the tool very quickly. They do it in a room used for nothing else but planing because of the mess it makes.

[Bill Houghton]

They do it in a room used for nothing else but planing because of the mess it makes.

When I've cut rigid foam (mostly shipping foam - white stuff), I've had the impression there was a sudden snow storm in my shop. I can imagine the blizzard you'd get with a power planer.

[John Sanford]

It depends a lot on the type of foam. For extruded polystyrene (i.e. Styrofoam, the blue stuff and Owens-Corning's pink stuff) and expanded polystyrene, aka "beer cooler foam", any cutting tools other than a knife will generate a lot of particulates. The particulates get reallllll staticcy. If all you're looking to do is edge planing, you can do it with a Surform, works great. Hot tools are used extensively for cutting EPS, both the wire tools and hot knives. You can also use an electric carving knife, tablesaw, bandsaw, jigsaw, and router. If you need to flatten a face or the like, you can simply use an straight bit in your router, with a sled, moving the router quickly. Lotsa blue (or pink, or white, or ...) stuff floating around.

There is also expanding polyurethane foams, which are related to Gorilla Glue. Great Stuff (insulation in a can) is one of these foams. I have worked it with a Surform, not as friendly to work as polystyrenes. It is a less consistent texture.

I tried to use a regular handplane on the EPS, it doesn't work very well unless the blade is super duper sharp because of the compressibility of the foam. If you've ever cut EPS with a knife, you'll understand.