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Old Sep 13, 2012, 05:42 PM
Altitude is my friend...
Depronicus's Avatar
Southern California
Joined May 2009
1,615 Posts
Quote:
Originally Posted by anantken View Post
...what you guys are using for hinges...
Blenderm rules!

A lifetime supply for sixteen bucks.
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Old Sep 13, 2012, 05:45 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,929 Posts
Also, make sure you wipe all the sanding dust off the surfaces. Static cling keeps the fine dust on the surface and kills tape adhesion. A damp cloth will do the job. ('course then you have to let the surface dry, or wipe with lint free cloth)
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Old Sep 13, 2012, 07:50 PM
just Some Useless Geek
Chicagoland
Joined Oct 2008
2,543 Posts
I am actually starting to use those nylon live hinges (DuBro, HK, etc.) that you stick into the edge of the surfaces. If I use three or more hinges it gets rid of all the control surface rock that shows up in taped hinges.
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Old Sep 13, 2012, 07:58 PM
Registered User
NorCal
Joined Dec 2009
1,716 Posts
Quote:
Originally Posted by A Useless Geek View Post
I am actually starting to use those nylon live hinges (DuBro, HK, etc.) that you stick into the edge of the surfaces. If I use three or more hinges it gets rid of all the control surface rock that shows up in taped hinges.
Oh Oh, I think I understand a loss of control of a new plane I built. I used those hinges for the first time and cut slots in the foam for the hinges which left a gap of course. Live and learn, glue them on top.
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Old Sep 13, 2012, 08:29 PM
Altitude is my friend...
Depronicus's Avatar
Southern California
Joined May 2009
1,615 Posts
Quote:
Originally Posted by A Useless Geek View Post
...those nylon live hinges (DuBro, HK, etc.) that you stick into the edge of the surfaces...
Many of the major manufacturers of high-end 3D planes insist that we seal the gap between the leading edge of the control surfaces and the trailing edges of the wings and stabs. Precision Aerobatics is adamant about it.

Here's a blurb on why it should be done.

Using tape for the hinges seals the gap for you.
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Old Sep 13, 2012, 08:36 PM
Warriors
United States, MI, Farmington Hills
Joined Apr 2012
69 Posts
Quote:
Originally Posted by A Useless Geek View Post
I am actually starting to use those nylon live hinges (DuBro, HK, etc.) that you stick into the edge of the surfaces. If I use three or more hinges it gets rid of all the control surface rock that shows up in taped hinges.
You got it right. I have built Polaris plane. My Aileron control surfaces are easily moving up and down vertically. So there is always some vertical up or down movement when ailerons are operated. Also tape has started to come out. I sanded both the surfaces and tried cleaning them just by tissue paper, but I guess that was not enough.

So after putting those nylon hinges, do you also put the tape to cover the gaps. Also do u cut the forward edge of the control surfaces in 45 deg bevel fashion or you just keep them straight.

Thanks
Anant
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Old Sep 13, 2012, 08:41 PM
Warriors
United States, MI, Farmington Hills
Joined Apr 2012
69 Posts
Quote:
Originally Posted by springer View Post
Also, make sure you wipe all the sanding dust off the surfaces. Static cling keeps the fine dust on the surface and kills tape adhesion. A damp cloth will do the job. ('course then you have to let the surface dry, or wipe with lint free cloth)
I think thats what happened with me. I sanded the trailing edge of wing and leading edge of control surface but cleaned it with just tissue paper. That resulted in fine dust on tape.

So after cleaning with damp cloth, do u spray some adhesive (eg 3M Spray adhesive) to make those surfaces free of any foam dust and then put the tape on it.

Thanks
Anant
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Old Sep 13, 2012, 09:00 PM
AKA Don
bz1mcr's Avatar
United States, MI, Houghton Lake
Joined Dec 2002
7,642 Posts
I love Blenderm for hinges. It sticks well and it is strechy enough to be very tolerant of abuse and keep working. Check your local medical supply house or online places like http://www.jrsmedical.com/CORE_WOUND...FYHu7Qodi0Ozaw
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Old Sep 13, 2012, 10:55 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,929 Posts
anan: I haven't sprayed anything on the surface before taping, although after applying the tape, I do run the handle of an Xacto knife over it to insure it has "wetted" the surface of the foam completely. I apply a fair amount of pressure, enough to imprint the foam a bit. I've used both blenderm and packing tape, and it seems for me, it depends on the plane. If I am using the tape as a skin as well as hinge, I'll use the packing tape, while on the half sheeters (small 20-25" spans) I'll use the blenderm alone for hinges and not skin with packing tape to save weight.
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Old Sep 14, 2012, 02:17 AM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
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I keep coming back to the cloth hinges as used on the old Control Line planes.
They work really well, and cost and weigh next to nothing.
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Old Sep 14, 2012, 05:05 AM
Registered User
Michael V's Avatar
United States, CA, Torrance
Joined Apr 2012
724 Posts
Quote:
Originally Posted by Depronicus View Post
Many of the major manufacturers of high-end 3D planes insist that we seal the gap between the leading edge of the control surfaces and the trailing edges of the wings and stabs. Precision Aerobatics is adamant about it.

Here's a blurb on why it should be done.

Using tape for the hinges seals the gap for you.
Yet slotted flaps are known to be more efficient because they help holding the boundary layer.
http://www.love4aviation.com/Dynaero...June+2003.html
So by the same token that leak can produce more efficient control surfaces. Granted in level flight it may cause a shortening of the wing aspect ratio.
I'd venture to say that it's not as black and white as it may seem, and only wind tunnel testing would really show real impact (positive or negative).

I'm new to this business, but I created hinges out of PVC (transparent blister material, same used for thermoforming canopies)
You cut a small strip, fold it in the middle back and forth. I drill a small hole on each mounting sides (for the glue to be), then slit the MPF, put a drop of gorilla glue in the hole on the hinge, insert in the slit and I have a perfect hinge. Light, cheap, easy to make, slick, takes no space at all, easy to install. And the gap is really minimal (no photos yet, but to come)

I tested it by pulling it apart, the hinge breaks before the glue joint or the foam connection, and that is with a very hard pull.
I also tested the hinge to see if it breaks after folding it a thousand times, and it doesn't. I couldn't make it separate by folding. Next is test flights.
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Last edited by Michael V; Sep 14, 2012 at 05:11 AM.
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Old Sep 14, 2012, 07:14 AM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
10,736 Posts
Quote:
Originally Posted by Whiskers View Post
I keep coming back to the cloth hinges as used on the old Control Line planes.
They work really well, and cost and weigh next to nothing.
I have done this with Monokote before, sticking short strips of the adhesive side together, then cutting into pieces that can be ironed on. I was just thinking the other day about trying this on a foamie. Though you would need a better adhesion surface than the bare foam affords. Probably a strip of packing tape over the edge of each mating face. Then you don't even have to bevel the edge.

Or even the sewn hinges. Loved those for small RC glow models.

Ken
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Old Sep 14, 2012, 09:45 AM
Exodus 4:13
bhoov128's Avatar
United States, FL, Davenport
Joined May 2012
9,434 Posts
Quote:
Originally Posted by A Useless Geek View Post
I am actually starting to use those nylon live hinges (DuBro, HK, etc.) that you stick into the edge of the surfaces. If I use three or more hinges it gets rid of all the control surface rock that shows up in taped hinges.
I've used demonGti's tape hinge method that I learned from his build guide for the Easy Build Ultimate. I've never had any control surface rock or instability, the ailerons hardly move in any way but the one they're supposed to. FFF and good ol' 3m packing tape. demonGti's illustration from his build guide is attached below - black lines are a side-view of the wing/aileron surfaces, red denotes the tape. You accomplish this by setting the aileron upside down on top of the wing, taping tightly, laying it flat and taping the other side. Demon if you happen across this post I hope you forgive me for sharing your illustration from the build guide.

And if you already knew about this and are using it.... sorry
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Old Sep 14, 2012, 10:16 AM
Warriors
United States, MI, Farmington Hills
Joined Apr 2012
69 Posts
Thanks guys for all your responses. Yesterday i tried what bhoov128 has mentioned. I didn't sand any surfaces. I made 45deg cuts to both the surfaces with x-acto knife (to get maximum movement). Then taped it tightly with 3M Packing tape (that you can get anywhere e.g. walmart http://www.walmart.com/search/search...m+packing+tape) on both side as bhoov128 showed in the attachment and it worked great. No slipping, no foam sanding dust, packing tape grips to MPF very well. I used 2inch wide Packing tape. Now I am a happy pilot. I am new to this hobby and learning new things everyday.

Thanks
Anant
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Old Sep 14, 2012, 11:51 AM
Registered User
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United States, PA, Beaver
Joined Sep 2001
3,524 Posts
FWIW, I use SCotch 810 magic tape. http://www.staples.com/Scotch-810-Ma...product_504662 Seems to really work better than any other tape. After applying I set it with a covering iron set low enough to heat the tape/glue to press into the foam, but not enough to melt the foam or tape. It is lighter and thinner than the packing tape (same here though, use a good quality tape; it matters) and the 1" is more than enough to make a strong hing. You just have to be careful to get the alignment right as there is less room for error.
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