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Old Jul 24, 2006, 12:52 AM
Ego varius quis.
Cheesehead's Avatar
Wisconsin
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How to make/get really thin foam?

I've been tinkering with indoor flight lately, but I seem to be limited by the fact that all I own is "thin" (3mm+) Zepron, as opposed to something thinner. I've also got 5mm low-density EPP.

What's a good source for large panels of really, really thin foam? Styrofoam plates are too small for most wings, but are just the right thickness. Super-thin (2mm) EPP might work nicely for "skinning" EPS ribs for a flexible wing, but I doubt that a homemade hot-wire cutter would work.

So, what should I do? I've got power transformers and associated parts (incl. rheostats and assorted load resistors), and I can get nichrome. Should I cut my own foam, or try and find bigger plates? Should I stick with EPS, or use EPP?

Thoughts?
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Old Jul 24, 2006, 01:07 AM
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Columbus,Ohio
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You could check here, might have something you can use.

link here
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Old Jul 24, 2006, 02:37 AM
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USA, OR, Damascus
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Foam cutters
http://www.rcgroups.com/forums/showthread.php?t=243271
http://www.utahflyers.org/

2mm foam here
http://www.depronusa.com/
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Old Jul 24, 2006, 11:34 AM
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http://www.rcgroups.com/forums/showthread.php?t=243271
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Old Jul 24, 2006, 01:51 PM
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HAH! Beat ya, Brad!
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Old Jul 24, 2006, 02:38 PM
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Crawley, West Sussex, UK
Joined Jun 2004
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> I doubt that a homemade hot-wire cutter would work

It does, although it takes more care with adjusting the runners because any taper is more obvious in a thin sheet.

Over here we get 2mm EPS in long rolls for sticking to walls under wall paper.

You can also get 0.5mm, 1mm and 2mm depron
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Old Jul 24, 2006, 03:02 PM
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Quote:
Originally Posted by Cheesehead
So, what should I do? I've got power transformers and associated parts (incl. rheostats and assorted load resistors), and I can get nichrome. Should I cut my own foam, or try and find bigger plates? Should I stick with EPS, or use EPP?

Thoughts?
Power transformers are good - especially one that will drop wall voltage to 24V. It should put out a few amps minimum - 100VA (~4 amps) is even better.

Forget the load resistors and rheostats; a *good* quality dimmer (Leviton makes one rated for 600W) or ceiling fan speed controller is what you are after. I built my own PS, but if I had to do it again, this is what I'd use.

Forget NiCr - use stainless steel instead; it takes less juice, and (much) more tension. Anything in .015 to .020" thickness is good. Braided or solid doesn't matter.

Thread on home-made foam cutters: http://www.rcgroups.com/forums/showthread.php?t=287621

Wire: http://www.cabelas.com/cabelas/en/te...equestid=49376


Brad (sheesh - I got beat to my own thread I bookmark the good ones too )
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Old Jul 24, 2006, 03:13 PM
Ego varius quis.
Cheesehead's Avatar
Wisconsin
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Quote:
Originally Posted by arx_n_sparx
Power transformers are good - especially one that will drop wall voltage to 24V. It should put out a few amps minimum - 100VA (~4 amps) is even better.

Forget the load resistors and rheostats; a *good* quality dimmer (Leviton makes one rated for 600W) or ceiling fan speed controller is what you are after. I built my own PS, but if I had to do it again, this is what I'd use.

Forget NiCr - use stainless steel instead; it takes less juice, and (much) more tension. Anything in .015 to .020" thickness is good. Braided or solid doesn't matter.

Thread on home-made foam cutters: http://www.rcgroups.com/forums/showthread.php?t=287621

Wire: http://www.cabelas.com/cabelas/en/te...equestid=49376


Brad (sheesh - I got beat to my own thread I bookmark the good ones too )
I think mine's rated to at least 120VA, and I've got an 18v transformer that should do at least 7A. (Huzzah for industrial-grade electronic surplus!)
I'm tempted to try your foam-slicer-thingamajig, but I have no place to put it. I think I'll try hitting the local grocery stores for bigger plates before anything else. (That, or make a polyhedral wing.)
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Old Jul 24, 2006, 06:53 PM
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flypaper 2's Avatar
Kingston, Canada
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I cut pink foam down to 1 MM with a wire cutter, then cover it with Doculam for a tough wing skin. The old EZ OK wings were skinned this way. I just copied it
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Old Jul 24, 2006, 11:10 PM
Registered User
Lancaster, OH
Joined Mar 2004
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Flypaper,

What thickness of Doculam do you use. What width works best
for you. I'm getting up courage to buy some.

WWII
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Old Jul 24, 2006, 11:14 PM
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United Kingdom, England, Redditch
Joined Jul 2006
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Warm it gently 75c 30 seconds and then press it with a heavy roller, two thick metal plates and a heavy truck driving over them will do too also makes the foam more dense and heavy so I don't know if that right for your needs
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Old Jul 25, 2006, 01:25 AM
Ego varius quis.
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Wisconsin
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Quote:
Originally Posted by foxabilo
Warm it gently 75c 30 seconds and then press it with a heavy roller, two thick metal plates and a heavy truck driving over them will do too also makes the foam more dense and heavy so I don't know if that right for your needs
Tempting, actually.

What, exactly, is Doculam? I'd like to cut my airfoil out of foam, but it's always been too fragile. This sounds like a possible solution.
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Old Jul 25, 2006, 06:40 AM
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Kingston, Canada
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This is .002 thou thick. 13 1/2 in wide. Handles much like monocote inasmuch as it can be heatshrunk and stretched around the tips. Makes a nice stressed skin structure. Can be painted with no prior preparation. I get mine from Staples. Made right here in the best country in the world It's a clear sticky back plastic film made to protect documents among other things.
PS : It's cheap.
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Old Jul 25, 2006, 12:22 PM
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Doculam Discoveries: http://www.rcgroups.com/forums/showthread.php?t=274520

I haven't tried this stuff. Personally, I have a real hatred for anything iron on (as in I really suck at it ) Doculam comes in various thicknesses - you want the thinnest stuff - I believe 1.5 mils (whatever that actually is ) It comes in a roll of 500 or 1000 ft, and is about a foot wide.

Brad
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Old Jul 25, 2006, 01:06 PM
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Wisconsin
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Interesting. Perhaps I should make a foam-and-doculam wing?
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