Custom/Hybrid Whats best way to cut polstreyne foam

[bobob729]

Well im trying to cut my tray smooth amd cut out my foot holds. Is there a good way to the footholds out. A knife wasnt working so well so figured id get some insite on this?

 

[The Penguin]

a hot knife?

http://www.harborfreight.com/130-watt-heavy-duty-hot-knife-66182.html

 

[BruceSki]

I used a sheetrock saw, didn't want to breathe the fumes from the hot knife method.

 

[WFO Speedracer]

Air body saw, rotozip, dremel with a rotozip bit, if you are really poor a regular drill with a rotozip bit, a jigsaw with a metal cutting blade, a close quarter hacksaw, a chainsaw for those really tough footholds

 

[Cannibal]

I use a carpentry razor blade in a vise grip heated to red hot with a propane torche...poor man's hot knife.

I didn't notice any fumes or smoke coming from it with this method...I'm not saying you should do this in a coat closet either, but a garage with the doors or windows cracked would be fine IMO.

 

[bobob729]

well i waswanting to try and use a hot wire if possible but the hot knife was on the list i have been using a small blade to cut the foam so far until i broke two of them. so now i need other options.

 

[bobob729]

what rotozip bit works best for doign this i already have a dremel so it wouldnt be hard to finish the rest with just a bit.

 

[Cannibal]

I have one of those oscilating multi-tools and I'm going to try that on mine the next time I need to cut some. Should cut it very clean and with ease.

 

[harris414]

dremel with rotozip and just dig out with hand, easy and fast

 

[harris414]

mine looks like this

 

[NVJAY775]

It's a bit messy, but for most of mine I use an angle grinder with a flapper disc on it. Works VERY fast and can take big bites, but is awesome for shaping and removal. And I will use a flapper disc on the dremel too. Very speedy and smooth. I like catching a buzz, so maybe I'll hot knife it next time.

 

[Waternut]

I actually organized my tool box using polystyrene and a dremel with a tile cutting bit. You can get really clean and accurate cuts with a careful hand. I've been using that same bit for 3-4 years on metal, fiberglass, and carbon and it's still sharp as can be. When cutting something like foam or fiberglass though, you need to take it slow. I say slow but you can cut a section for footholds in your hull in a minute or two. Just if you go too fast, the bit will want to chatter and you'll end up with a gigantic hole in the material instantly.

http://www.amazon.com/Dremel-562-Tile-Cutting-Bit/dp/B00004UDIC

 

[Vumad]

I prefer to use wood blades. A sawsall with a good blade or an airbody saw with a modified sawsall or hacksaw blade. They will cut through foam and glass pretty quick. The sawsall is hard to control but the airbody saw is not. I also have an old handheld tree saw that's about 12" long I like to use on foam (no good for glass). I also like using my Die grinder with a toothy carbide tipped metal bit. The carbide tips are very expensive, cost about $50, but makes short work of glass and foam and lasts forever. I used to use stone bits but when used on glass they quickly loose their shape and have to be replaced. The money spent on carbide bits is worth it since they are over-engineered for the job so they just keep going and never deform. For more detailed stuff I use a dremmel with a drum sanded or sand by hand with a 40 grit.