How do you cut holes in EPP? - RC Groups
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Jan 19, 2001, 04:17 PM
Registered User

How do you cut holes in EPP?

This is probably a stupid question but...

In the past I have used a dremel with a pointed cutting bit to eat out pockets in foam for servos, receivers, etc. I am getting ready to do an all EPP zagi-like wing and got to thinking about using a hot knife. Maybe attaching an x-acto blade to a soldering iron or something. I am thinking I might be able to get cleaner, more accurate cuts that way. Plus, less dust everywhere. Does it work?
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Jan 19, 2001, 10:00 PM
Registered User
You might want to have plenty of ventilation--- I think the fumes from burning EPP is quite toxic.

You can also heat up a length of coat-hanger wire or music wire with a torch. Many foam wing crafters use electric soldering irons (Weller) with various-sized wire loops in them to create custom pockets. Or just have at it with a screwdriver and cover it up with covering film like the rest of us. :-)

Jan 20, 2001, 03:17 AM
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Clive Henry Jones's Avatar
You are a Butcher!

Screwdriver indeed!!

I use a bread knife.

Jan 20, 2001, 03:36 AM
Caution:Makes sharp left turns
Troy's Avatar
First I outline the servo pocket area with a sharp razor blade/Exacto to desired depth (mark the knife blade). Then I carefully (no rush)use my Dremel with a toothy side cutting bit. Start from the center working slowly out towards the edges. When you get close to the edges stop and pull foam out manually. It should come out in thin slivers leaving a clean wall behind. I get very acurate hole depth and shape. I also use the hot poker tool to melt away long holes through EPP (servo wires, etc). The hot poker can work for servo pockets too. I just feel I have more control with my dremel. Find what works for you and stick with it.

[This message has been edited by Troy (edited 01-20-2001).]
Jan 21, 2001, 11:51 PM
Registered User
If you're cutting out pockets, it's pretty easy to do: Cut the square pocket from the front, don't cut too deep... At 90 degrees to the first cuts, cut all the way through the edge and the pocket. When you're done, the pocket slides right out. The resulting Cut in the side can be glued with goop easily.
Jan 22, 2001, 11:24 AM
Registered User
Have you tried a 1/4 inch routing bit on the Dremel? I just built a Push-E Cat and they suggested the bit with the router attachement, and it rocks. Very clean cuts with lots of control. Too many fluffies flying around my garage/house now, but who said it had to be clean? The router base accessory allows very good depth control, as well, but ran about $40 at Sears. I think I found it for $5 less at Wal-mart the day after I bought it. Wish I could take credit for this, but it's what Garrison Aerodome recommends. Hope this helps.


PS, I accidentally almost cut the canopy in half when I free handed the canopy with a cutting bit (ie. rotozip/drywall style). Much better control with the router......
May 16, 2001, 12:31 PM
Registered User
I used this technique with Pink foam for my T-52, and it should work well on EPP, too:

I first make a rectangular shape with Nichrome wire with one side open, and solder it to an old Radio shack breadboard. I connect the two ends to a variable power supply, and adjust the current till I am happy with the melting. Now by placing shims of the right thickness between the edge of this PCB and the foam surface, I can adjust and maintain the depth of the cut as I slide it along. The removed foam block is taken out with a toothpick. Produces very clean, accurate cuts. Of course, do it in a well ventilated area.
May 16, 2001, 05:07 PM
Registered User
Darwin's Avatar
Quick note: EPP is not toxic in the amounts that a modeler will see. Rather, it is an irritant for eyes, nose, throat and bowels. (Blech!)

Urethane foams are VERY toxic when heated to the gassing point (sanding, sawing, routing OK). Please remember this. Styrofoam, EPP = OK, Urethane = DEAD.

TOP 2 Tools for primary shaping of EPP:
#1) Hot wire (FeatherCut a personal favorite)
#2) 14" Delta Bandsaw

#1) Table saw (Works fine for the first bit until the rising teeth grab the work piece and fling it back out at you, leaving you shakey, panting, weak kneed and counting your digits).

My top 10 favorite tools for cutting holes, pockets slots etc in post-hot wire EPP:

#1) 1/2 HP Porter Cable Plunge Router with a Roto-Zip tool.
#2) 1/2 HP Porter Cable Plunge Router with a 1/2" straight cut carbide tool.
#3) Dremel on a router base with a Roto-Zip tool.
#4) Dremel on a router base with a 1/4" router bit tool for pockets.
#5) Dremel on a router base with a 1/8" router bit tool for control cables.
#6) Forstener Bits in a drill press.
#7) El-Cheapo snap off utility knife with a really thin blade.
#8) #26 Exacto blade.
#9) Weller soldering gun with standard tip for control cables.
#10) Weller soldering gun with 12GA copper wire shaped to whatever I need for a pocket.

God I love this job.
Feb 05, 2010, 11:06 PM
Sl0flyer's Avatar
Wow.. old post huh?

These days I'd probably use a Phlat Printer