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Old Feb 24, 2013, 02:13 AM
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USA, OR, Salem
Joined Dec 2010
20 Posts
Before I found Kevlar thread at my local fly tying shop I used un-waxed dental floss. Worked great! I wrapped it down flat, soaked it with CA. Dental floss is tought as nails and about as strong and CHEAP!

I use Kevlar thread or tow now and CA it just to keep it from moving around on the spar. You don't need to glue it down for added strenght.

As far as twist, I can not remember ever having a twist in a wrapped spar. Most of the time, you wrap just enough to keep any spar cap( carbon or what ever) in place. Most of the wraps are in the wing connector box area. I don't ever remember a recommendation thats you torgue the wraps down to a pound or ounce rateper inch, so where is the twist coming from?

Gary
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Old Feb 24, 2013, 03:35 PM
Chuck it and see!
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UK, Cambridgeshire, Huntingdonshire
Joined Sep 2006
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I guess the twist is coming from over tension of the wrap. But lets get a grip, only one guy has mentioned it right? If you are spar wrapping on a spar with ribs, leading edge and trailing edge fitted that chance of a twist forming is less still. remember the wrapping is just to keep the spar top and bottom from separating as the spar flexes under load.
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Old Mar 07, 2013, 02:59 PM
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Joined Apr 2005
368 Posts
Recently I had to repair the left outer spar on my Wanderer as a result of a gust of wind lifting the Wanderer's right wing just before landing and the left wingtip's initial contact with the ground accompanied with that unwelcome 'kra-crunch' sound.

Could not find my small supply of kelvar tow but had a old sample of Glide (no kidding) dental tape which felt slick but I could not scrape off any wax from it with my fingernail. CA'ed the spar after aligning the wing and used thin ply to 'sandwitch' the spar and wrapped the Glide dental tape with epoxy and the repair has held up well so far.

Checked the Glide floss website and their dental tape is available 'lightly waxed.' I did check my old sample dental tape to see if it would stay embedded in epoxy after the epoxy set up and I could not pull out my dental tape from the hardened epoxy.
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Old Mar 07, 2013, 05:45 PM
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USA, CO, Fort Collins
Joined Sep 2010
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I thought Glide was Teflon-coated. I haven't ever tried gluing Teflon, but if epoxy is sticking to it, okay...
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Old Mar 07, 2013, 06:46 PM
Jim C Patrick
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Shenandoah County
Joined Jan 2008
786 Posts
The glue doesn't have to stick to the wrap material. It just needs to keep the wrap from sliding spanwise.
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Old Mar 07, 2013, 06:58 PM
Unrepentant Paragon addict
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United States, OK, Moore
Joined Jan 2006
2,516 Posts
Quote:
Originally Posted by HIR/Cer View Post
Recently I had to repair the left outer spar on my Wanderer as a result of a gust of wind lifting the Wanderer's right wing just before landing and the left wingtip's initial contact with the ground accompanied with that unwelcome 'kra-crunch' sound.

Could not find my small supply of kelvar tow but had a old sample of Glide (no kidding) dental tape which felt slick but I could not scrape off any wax from it with my fingernail. CA'ed the spar after aligning the wing and used thin ply to 'sandwitch' the spar and wrapped the Glide dental tape with epoxy and the repair has held up well so far.

Checked the Glide floss website and their dental tape is available 'lightly waxed.' I did check my old sample dental tape to see if it would stay embedded in epoxy after the epoxy set up and I could not pull out my dental tape from the hardened epoxy.
Just ordered some of this stuff off flea-bay, and it arrived today. It's the best looking kevlar I've come across, in terms of ease of application. Hope this helps someone!

http://www.ebay.com/itm/110996914776...84.m1497.l2649
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Old Mar 07, 2013, 08:55 PM
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United States, MI, Hastings Charter Township
Joined Apr 2005
41 Posts
Just ordered some, thanks for sharing!
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Old Mar 08, 2013, 08:48 AM
Kurt Zimmerman ≡LSF 4461≡
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Montrose, NY
Joined May 2003
1,349 Posts
Ya know, I've been giving this some additional consideration. If you use a thinned down carpenters glue, just to get it "wet" enough so it will absorb into the fibers of the wrapping, then wipe away any excess you can probably save yourself some weight and get the same job done. Just saying...
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Old Mar 08, 2013, 01:22 PM
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Joined Apr 2005
368 Posts
LV, thank you for the 'fee-bay' lead for the kelvar. Should order some to replace my misplaced kelvar. Built that Wanderer with Satellite City CA and Hobby Lobby epoxy, the latter used for joining the inner and outer wing spars and the wing joiner tubes, and everything has held up well over the years. The spar break occured about 1/2" beyond where the spars were epoxied together, and I figured out why it broke there.
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Old Aug 22, 2013, 12:12 AM
Full-Blown RC Junkie
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United States, MO, Liberty
Joined Jun 2011
365 Posts
The eBay link in post #21, can anyone confirm that this was in fact unwaxed Kevlar? And does it resemble a ribbon shape or is it round like thread? My main criteria is CA absorption.
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Old Aug 22, 2013, 09:35 PM
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Pittsburgh, PA
Joined May 2008
1,022 Posts
Just throwing in another option in the hat here. Ive used spiderwire braided 50# and it worked well. Takes the CA too being braided and is a bit thinner than mono for the strength.
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