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Wingtip repair what glass fibre cloth do I need?

Westerhuis

Active Member
Hi all

Unfortunately I damaged the wingtip on my RV8 :mad: and I wondered what glass cloth I should order for the repair and what resin and hardener you guys use? West System?

I'd like to add a bit of glass to at the top of the wing and add a strip across the seam inside the wing to add strength.

Where would you get it from? And any tips to do the repair welcome.

Thanks

Roger

cfpJxMFtmRuRuy6o4gD38rNn12-6_kgnAKI3qydRReo4SOciFkiMvYE7CG6d-yPtABKkdQpaDCsHQKmz50AyQKSMcLPobUinTqVo0ou37oROlbulD0CMx9_uJqjvxoX1gNdv6VVi8Czcu3u_FpEAObwlX4jSRhOa2roPuSusLdL_PEjFIqo84UJocaWqGQDUI80Z1IcrelyV80QNqqRLgmZ-tMFti2EQpyN9utfeyU4bwUbXnX0y7WSF2lFgPaJK7OaLZV3D9sya-bE767iDiSOmI4SgRWJH99QCyjFRS3tXUJSUEpnZSYybKj4HZQhpyCli5QLwf93lFuhHKn7m_DoaMzkQT-NyQT21rngvPqHSC_cAfei9U1ZOHMhcoflsmbcQbsL4cKp8apAXXS8RkF38HFBXt5wT3XYmdxM4SwXuYG7V4dm3OIhaVqtK3FLtOXlioIy_4ntEdzB2OEzG2ljxTNQzMeZP0ME5-oMf5BVq8-goWAJP3Z96szPyl3FXW5zqBLwBepe_4YVelx6UzKp0AFu9vOpddIGszWX6aj9YQcI7nQ03i1sZKhhPBIFnhEHd93iFpIVdqwHprP40rXkcLPnSioFKfgY5JRe6tDo3syq1uOzDka9PlZf08KU003gXM35OE4eD4fRKT8JeDHknPo_seU9LkEYX6oZcNl5q=w500-h1058-no
 
which tips are they? the older white polyester or the newer epoxy? if they are the older white tips i would just head down to the auto store or home depot and by a quart of polyester resin and a some cloth. most carry the bondo brand. the older white tips were pretty much made from the same stuff.

if they are the newer epoxy ones, then you have to use epoxy, polyester will not bond to epoxy. west is good stuff and available at most marine suppliers. a couple of layers of heavy cloth on the inside and a lot of filling and sanding and you should be good to go.

bob burns
RV-4 N82RB
 
Unfortunately I damaged the wingtip on my RV8 :mad: and I wondered what glass cloth I should order for the repair and what resin and hardener you guys use? West System?
I'd like to add a bit of glass to at the top of the wing and add a strip across the seam inside the wing to add strength.

Where would you get it from? And any tips to do the repair welcome.

You have a busted seam, so it will need more than just filler.

Wingtip and wheelpant repairs are pretty much the same. Here are how scarf joints are laid, with excellent sanding pictures from Doug, the repairer:

http://www.vansairforce.com/community/showthread.php?p=961431

The inside surface of the tip must be abraded heavily before bonding of any backing strips is attempted.

Any laminating epoxy will work. West is fine. Use 206 hardener. Plain weave 9oz glass is also fine; 7500, 7520. If the location has a lot of compound curvature, try 7781 8-harness. You must work in a warm place, so take the tip off the airplane and find one. And "search" is your friend. Lots of discussion about repairs, cloth, epoxy, methods.....
 
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Rocky,

Something like this https://www.aircraftspruce.com/catalog/cmpages/7781.php from Spruce would be suitable. I like lighter cloth for small repairs, for a wing tip more layers of lighter cloth is probably better than a couple of heavy layers. West is easy to use and readily available from yacht chandlers. Remove all the broken pieces and scarfe the edges, rough up well with 60 grit, get some kind of backing behind (a few layers of tape?) to hold the shape and lay up. Sand back when cured with a sanding disc to the surrounding profile, fill and paint. Get some help if you haven't done it before ...
Pete
 
Epoxy on Polyester OK

Epoxy resin is suitable for polyester repairs. Unsure if original part is poly or epoxy, use epoxy.
 
random thread direction

I would also use the random thread direction fiberglass cloth, not the orthogonal cloth because the square pattern of the orthogonal cloth shows thru paint. Random looks better.
 
Our go-to cloth for this type of repair is often Style 7725 which is a 300gm 2x2 twill cloth (about 10oz in your money). Lighter weights are available. The advantage of this cloth is it lays flat and will form around compound curves a lot easier than the standard 'boat cloth'. Should be readily available from your local suppliers. AC Spruce may even have it or a similar product.
Tip: Sit the wing tip on a table or similar with the damaged edge facing up. Use a large piece of peel ply draped over the repair and weight it down with clamps or similar hanging off it to hold the cloth in place. The cloth can tend to lift off the sharp corner of the wingtip if left to it's own devices.

Clive Whittfield
Auckland, New Zealand
RV6 wings on, nearly there!
 
...If the location has a lot of compound curvature, try 7781 8-harness...

I'm going to respectfully disagree. I think that 7725, sometimes called "Rutan BID," or more accurately "Jiran BID," or by it's Interglas equivalent 92125, is the best thing for this. It drapes well, saturates quickly, and builds thickness reasonably fast.

People keep trying to give me hundred-yard rolls of 7781, and I keep turning them down. It might be great for pressure molding or resin infusion, but I've found it to be hateful stuff for wet layup or vacuum bagged parts. The weave is so tight that it doesn't drape well, saturates slowly, and is reluctant to release air bubbles.

--Bob K.
 
Hi all

Unfortunately I damaged the wingtip on my RV8 :mad: and I wondered what glass cloth I should order for the repair and what resin and hardener you guys use? West System?

I'd like to add a bit of glass to at the top of the wing and add a strip across the seam inside the wing to add strength.

Where would you get it from? And any tips to do the repair welcome.

Thanks

Roger

cfpJxMFtmRuRuy6o4gD38rNn12-6_kgnAKI3qydRReo4SOciFkiMvYE7CG6d-yPtABKkdQpaDCsHQKmz50AyQKSMcLPobUinTqVo0ou37oROlbulD0CMx9_uJqjvxoX1gNdv6VVi8Czcu3u_FpEAObwlX4jSRhOa2roPuSusLdL_PEjFIqo84UJocaWqGQDUI80Z1IcrelyV80QNqqRLgmZ-tMFti2EQpyN9utfeyU4bwUbXnX0y7WSF2lFgPaJK7OaLZV3D9sya-bE767iDiSOmI4SgRWJH99QCyjFRS3tXUJSUEpnZSYybKj4HZQhpyCli5QLwf93lFuhHKn7m_DoaMzkQT-NyQT21rngvPqHSC_cAfei9U1ZOHMhcoflsmbcQbsL4cKp8apAXXS8RkF38HFBXt5wT3XYmdxM4SwXuYG7V4dm3OIhaVqtK3FLtOXlioIy_4ntEdzB2OEzG2ljxTNQzMeZP0ME5-oMf5BVq8-goWAJP3Z96szPyl3FXW5zqBLwBepe_4YVelx6UzKp0AFu9vOpddIGszWX6aj9YQcI7nQ03i1sZKhhPBIFnhEHd93iFpIVdqwHprP40rXkcLPnSioFKfgY5JRe6tDo3syq1uOzDka9PlZf08KU003gXM35OE4eD4fRKT8JeDHknPo_seU9LkEYX6oZcNl5q=w500-h1058-no

Hi Rocky,

You sent me pictures of the crack near the aileron and the above picture which I take to be the tip?

Does the crack run all the way from the tip to the aileron?
 
I'm going to respectfully disagree.

No problem here. You and Clive are both pros. 7725 is a standard with sensible properties for this repair.

Minor debate point; 7781's seven-over, one-under weave means the fibers can slide around rather freely. Here's an example, a 4-ply duct wrap.

http://www.vansairforce.com/community/showpost.php?p=1120096&postcount=12

We're down to head-of-a-pin stuff. Truth is, a fella could probably make this repair with a few plies cut from a burlap sack ;)
 
..........'Minor debate point; 7781's seven-over, one-under weave means the fibers can slide around rather freely. Here's an example, a 4-ply duct wrap.

http://www.vansairforce.com/community/showpost.php?p=1120096&postcount=12'.........

That's some clever work Dan and you are right, there is definitely more than one way to skin this particular cat.

..........'Truth is, a fella could probably make this repair with a few plies cut from a burlap sack'.............

And I would almost bet that's been done before now too:)

Clive
 
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Use 206 hardener..

Sorry for the potential thread drift. However, I am curious about this recommendation. Does the fast hardener perform better? I typically use slow and wondering if I am giving something up here.

Larry
 
Just speeds up the reaction time. It's coming into summer in this part of the world and warming up (About 75F in the workshop at the moment). Have been doing some small repairs using the fast hardener. At this temperature any resin left in the cup will start to exotherm in about 15 minutes. I should really be using the slow hardener to give myself a bit more time:eek:
 
No problem here. You and Clive are both pros. 7725 is a standard with sensible properties for this repair.

Minor debate point; 7781's seven-over, one-under weave means the fibers can slide around rather freely. Here's an example, a 4-ply duct wrap.

http://www.vansairforce.com/community/showpost.php?p=1120096&postcount=12

We're down to head-of-a-pin stuff. Truth is, a fella could probably make this repair with a few plies cut from a burlap sack ;)

Yep, here with clear resin the burlap is seen but not felt.
ix8r34.jpg
 
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