What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV-10 fairing cracks

Bill Boyd

Well Known Member
I have some cracking going on in the mold-in-place fairing at the base of the windscreen. A friend nearby (not a member here) has reported the same on his -10. This is cracking of the plies over the outside lower corners of the windscreen and has taken a year or better to appear. Thankfully, my bird is not yet painted; my friend's is.

I'm looking for suggestions on how to do the repair when the hangar warms up a bit this month. Hoping to shoot Stewart Eko this spring and this needs to be fixed first. Thanks, Dan and everybody. :D

Photos are rotated 90 for some reason - sorry.
 

Attachments

  • 66768317024__29EBA17A-DCBC-492F-9D01-F250F74F4710.jpg
    66768317024__29EBA17A-DCBC-492F-9D01-F250F74F4710.jpg
    262.9 KB · Views: 354
  • 66768319330__4C6E4EF8-22D2-44A5-84E3-2CE61C4B4BA1.jpg
    66768319330__4C6E4EF8-22D2-44A5-84E3-2CE61C4B4BA1.jpg
    444.4 KB · Views: 371
Looks like the layer may have been sanded through too far and possibly some moisture got between and cracked at the edges. I'd suggest grinding them area away and using a scarf joint feathered out to patch it up. make sure the surfaces are prepped and cleaned to help bonding new layers. also make sure the fiber is wetted all the way through as well.
 
My guess is the ply that looks separated was too “dry” (resin starved) when initially installed. Either the ply was dry, or not enough resin between plies. Any chance this top ply was installed after the plies below, and the surface wasn’t prepared properly?
 
The whole thing was laid up in one work session, wetted out with West Systems, squeegied with a credit card and carried to the plane on Saran Wrap so it didn't distort when picked up. It was sanded down later, of course, and probably too far...

Anyway, too late to avoid the issue - so the question is best repair technique. I'm sure the corner of the Cee Bailey transparency is just under the surface at this spot.
 
second pic looks like a delamination. Likely from air getting between the wetted out layers of glass. You can see the dome shape to it. It was being held down by the other side of the dome, which was later sanded off. I would sand it down and fix with bondo or micro.

First pic looks like a thin unsupported piece of resin with no support underneath. Tap with a screwdriver and break away all that will come out and fill with flox mixture and then fair with bondo or micro. If you bridge a gap like that, you either need filler underneath it or use more glass.

Larry
 
Last edited:
Damaged areas were hollowed out down to and slightly into the corners of the plexi with an oscillating multi-tool sander and filled with three layers of cloth and a micro slurry overcoat, then sanded down leaving only a slight bulge at the corners to avoid cutting too far into the repair patch. I'm happy with the results.

I have noticed a few patches along the length of the fairing which are not cracked or delaminating but are showing some raw/undersaturated glass ply on the outer surface with fraying and pin-holing of the weave. I went to address these last evening and got a rude surprise. Masked off the plexiglass, wiped down the fairing and brushed on a skim coat of neat epoxy that I planned to carefully finish-sand prior to paint. The resin coat beaded up on the fairing like water on a waxed car hood. Too late, I realized the Plexus polish I was using since flying had contaminated the fiberglass below the windscreen.

I managed to wipe the mess off before it set up, and now I'm wondering what product and process is likely safe and effective for prepping this area properly. I believe I need a solvent degreaser followed by some sanding maybe followed by another solvent wipe to surface prep this area for an epoxy sealer coat to fill the dry weave areas and pinholes. Can I get this at the auto parts store?

I was so proud of the contours and blended edges achieved on this fairing but it looks like I got the layup too dry somehow when I squeegied the resin into the cloth with a credit card. Then, in the 18 months of flying since then, I contaminated the surface with windshield polish. This is turning into a disappointment/challenge I didn't expect.
 
Damaged areas were hollowed out down to and slightly into the corners of the plexi with an oscillating multi-tool sander and filled with three layers of cloth and a micro slurry overcoat, then sanded down leaving only a slight bulge at the corners to avoid cutting too far into the repair patch. I'm happy with the results.

I have noticed a few patches along the length of the fairing which are not cracked or delaminating but are showing some raw/undersaturated glass ply on the outer surface with fraying and pin-holing of the weave. I went to address these last evening and got a rude surprise. Masked off the plexiglass, wiped down the fairing and brushed on a skim coat of neat epoxy that I planned to carefully finish-sand prior to paint. The resin coat beaded up on the fairing like water on a waxed car hood. Too late, I realized the Plexus polish I was using since flying had contaminated the fiberglass below the windscreen.

I managed to wipe the mess off before it set up, and now I'm wondering what product and process is likely safe and effective for prepping this area properly. I believe I need a solvent degreaser followed by some sanding maybe followed by another solvent wipe to surface prep this area for an epoxy sealer coat to fill the dry weave areas and pinholes. Can I get this at the auto parts store?

I was so proud of the contours and blended edges achieved on this fairing but it looks like I got the layup too dry somehow when I squeegied the resin into the cloth with a credit card. Then, in the 18 months of flying since then, I contaminated the surface with windshield polish. This is turning into a disappointment/challenge I didn't expect.

Depends upon whether or not it is silicone contamination. If not, wax and grease remover, done properly (wipe on with one cloth and wipe off with a clean one) will take care of it, but will need to be done a few times to get it all. If not, I would work agressively with laquer thinner or acetone, changing paper towels often, then follow with W&G remover. Silicone is a BITC$ to remove and why it is concerned a forbidden poison in any paint shop. NOTHING will stick to it. Be sure to tell you painter about this. They will need special prep, else you will get a nasty call from them after they spray the first coat of primer. Anywhere you placed your hand on the plane after holding the polish rag is now contaminated. The silicone won't just go away over time like other stuff.

W&G remover can be found at any auto paint supplier. There are water based varieties and solvent based. Ask the counter guy, but suspect the solvent based version is better in your case.

Larry
 
Last edited:
Thanks, Larry.

On advice of my painter, I hit the area twice with blue Dawn and water on a soft towel followed by a thorough rinse and dry. I plan to lightly sand the fairing and apply a test sample of resin to see if it sticks after this. I want to keep solvent exposure to a minimum since this area directly abuts my plexiglass windshield. If it turns out the area is still contaminated, I will seek out a water based degreaser from the auto paint supplier.

I am very cognizant of the hazard of silicone and have banned silicone spray lube from my shop and hangar for decades. I think it snuck in on me in the form of Novus plastic polish that I used once to remove a light scratch haze on the windows after the first year of flying. The internet says Novus has silicones; I cannot find the same claim for the Plexus I use all the time. I will obviously need to regard the fiberglass areas around all five windows with the same suspicion of contamination before shooting primer.

I just checked the West Systems website and found a recommendation for DuPont PrepSol or similar as a silicone decontamination product. I'm unable to find info on how safe this stuff is around plexiglass. I'm not willing to risk a crazed windshield unless I know it's deemed compatible.

UPDATE: just got off the phone with Desser/Cee Bailey. The only solvents they approve for decontaminating surfaces from silicone where contact with the plexiglass is a possibility are 100LL avgas and naphtha. That's what I'll roll with. Of course instructions everywhere for dealing with silicone stipulate white paper towels and forbid fabric rags/cloths due to high likelihood of leaching organics from fabric and possible presence of silicones in fabric softeners if you launder your own shop rags. Gougeon/West Systems website says water-sheeting during a rinse is a good indication of successful silicone removal. Good to know.
 
Last edited:
Back
Top