How do you make channels in foam? - RC Groups
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Sep 20, 2001, 01:40 AM
Just an average RC'er
Jim McPherson's Avatar

How do you make channels in foam?

I have a new terry that I'd like to reinforce with some carbon fiber strip that I have. I have seen others who have cut a thin (1-2mm) channel in the foam. The Terry is made of what looks to be a dense EPS foam. Every time I have atempted a thin channel in this type of foam it looks terrible and is very ragged. Any suggestions?
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Sep 20, 2001, 01:50 AM
Registered User
with a sharp dremel routing bit at high RPM, you should be able to make a smooth cut in just about anything
Sep 20, 2001, 01:54 AM

cut groves in foam

I use my dremel with a bit that I got at home depot or the local hobby shop , it looks like a
small ball at the end with streaks , it does a great job.You can also use a taper flute bit or a roto zip bit , you will have to do 2 or 3 pases with this one until you get the width you want.
I fasten a straight edge with tape or clamp it and let the dremel guide against its edge. wrap some tape along the bit to use as your gauge for your depth this way you wont go through the wing It works like a charm. good luck, geoff
Sep 20, 2001, 07:45 AM
Registered User
same here... dremmel all the way! i have had mine for 6 years now, and i find something new to use it for about every day!!
Sep 20, 2001, 08:10 AM
SEFF Contest Director
rcjunkie's Avatar
I've been using my soldering gun with that flat blade "foam cutter" that came with the soldering kit. I have the 100/140 watt soldering gun sold at Home Depot. With a steady hand, you can cut a small channel to lay wires or carbon fiber into. It works pretty good and it doesn't throw foam dust to every corner of my basement like the dremel does.
Sep 20, 2001, 09:40 AM
Most Exalted Windbag
For running the wires to the aileron servos on my Terry I merely pushed down the foam with a blunt object and then ran tape over it. For the very thin kevlar strengthening fibers, I didn't put in a groove at all.

For the servo I cut to depth around the edges with a knife, then plucked out chunks with tweezers and knife to depth and then smoothed out the bottom by pushing on the foam with a blunt object. You can collapse the individual spheres of foam to the point that they don't spring back, but before they rip away from adjacent spheres.

I didn't like the hard melted plastic that resulted from the soldering iron technique.


Sep 20, 2001, 11:02 PM
Registered User
A trick that works well in EPP is to cut the plunge lines
first, and then cross cut through the adjacent wall. You
get a clean cavity, then glue the slit line back together.

Can you get a thin blade through the material? Try one
of those 5" Repala fishing knives.
Sep 21, 2001, 01:02 AM
Cal Slope Criminal@DV
Duke58's Avatar
I've made custom foam cutting shapes by foarming 1/16" to 1/8' brass wire and attaching it like the tip on the solder gun , you can even make stops from small collars and mika placed on the wire befor bending. Controlling the temperature can be done by timed trigger pulls or a lamp dimmer. With a little trial and error you will be cutting perfect groves in your wings or whatever.

Sep 21, 2001, 09:00 PM
EFlight=Fun,Big-T=BIG FUN
Dremel tool with the dremel router base and the bit that looks like a roto-zip bit (spiral flutes all the way to the end).
It cuts a good 1/8' wide slot.
Use a piece of alumimun angle for a guide and it cuts nce and straight.
Use the smaller bits for narrower slots.
Do have a vaccum running close at end.
After cutting the slot, use a popiscle stick to push out the cuttings stuck in the slot.