Repaired AFS W95 fuselage wing inserts that were pulled out.

First, thanks for all the advice on how to go about doing this repair.

Here is a detailed guide on repairing an AFS W95 foil that had the wing inserts partially pulled out after a gust picked up the whole kit (board/foil attached to mast/sail) and threw it 30 feet down the beach with the right wing tip hitting the hard packed sand upside down so it pulled away from the fuselage, a force which it was not designed for. Other than one wing screw being bent, and the inserts pulled out slightly, there was no damage to the F770 wing, stabilizer, T-bar fuselage/mast, and Goya Bolt 135 board and foil box.

1) the inserts were pulled out ~3 mm and were also crooked, use a 70-100 mm M6 zinc plated steel bolt to straighten the crooked inserts out (a 100 mm SS screw bent doing it).
2) using a straight M6 bolt or screw with ~30-40 mm of threads, screw it into the insert (they are through hole inserts) until it bottoms out inside the fuselage, then keep turning to force the insert out with a minimal amount of damage, you may be able to reuse the old inserts if they still catch the grooves in the holes.
3) clean up the fuselage saddle with a small sharp chisel and sandpaper, then use a 1/4" round file to bevel the tops of each hole (or Dremel with grinding tip). Make sure the saddle is level side to side, since mine was not around the holes, check that the wing seats in saddle without rocking due to high spots.
4) take slightly over sized A4 SS blind inserts (original through hole inserts were 8.4 mm OD, new inserts 9.0 mm OD advertised, 8.8 OD actual (off of eBay from the UK) and treat the outside with muriatic acid tor 15 min., then hot distilled water, followed by 100 grit sandpaper between the threads, thread surface, and bottoms.
5) drill insert holes a little deeper with a drill bit the same size as the existing holes so the longer blind inserts will thread in, blowout holes with compressed air.
6) mount inserts onto M6 bolts with a nut locked onto insert so that bolt does not bottom-out inside of the insert, screw in using a socket wrench while applying pressure from the side so inserts go in straight, mine were all bent in the accident to the right side (with foil upside down) and new inserts wanted to tilt to the right to follow old holes. Once I got the new inserts in "straight" by eye balling with pressure on bolt shaft, they stayed straight with light pressure on the bolt head, but once pressure was released the bolt head wanted to go to the left.
7) use a dental pick to scratch up the insides of the holes including bottom, blow out again, and then clean out holes with Q-tips soaked in 70% isopropanol (lots of carbon dust inside) repeat until clean. Dry holes with hair dryer.
8) mount foil upside down via fuselage, in front of the mast, in a vise with a pipe clamp (used 2 layers of 1/16" thick plastic to protect fuselage). Take a string with a lead fishing weight attached to the end, and tape string to top back edge of mast so that weight hangs down the length of the mast past the mast head, adjust fuselage in clamp until the mast is straight with the string and then tighten clamp. Can then check alignment of stab. by putting a level across it, shim as needed to get level. This is very important for getting the wing inserts straight.
9) fill insert holes in fuse. with SixTen West Systems epoxy using mixing tip "after discarding first inch of mixed epoxy to make sure epoxy ratio is correct" (45 min. working time at 72 degrees F, but if you are going to move something do it right away to avoid making air bubbles in the epoxy), use steel end of dental pick to push epoxy to bottom of holes and into walls, then refill holes with epoxy.
10) screw inserts into holes wiping away the epoxy as it gets pushed out (Q-tips work good) making sure the inserts go in all the way (locking nut makes it hard to see), break locking nut to release bolt from insert, remove bolt and coat lower bolt threads lightly with grease, then screw bolt back onto insert and screw into the bottom of the insert finger tight leaving nut loose on the bolt shaft.
11) now for the tricky part, with stabilizer level and mast straight (check in case fuse. moved in clamp) place a level across wing saddle, and place an adjustable T-square on top of the level, with the slide extending down the side of the level. While holding the level so bubble is centered, align T-square slide against the bolt head and loose nut on shaft (nut faces aligned with bolt head faces, both are approximately the same width) to align the bolts straight. Mine would go straight (but not further) under light pressure, but then when pressure was removed relaxed crooked to the left, so I put duck taped on bolt heads and then wrapped tape around fuselage to keep bolts straight until epoxy cured. Once the epoxy setup, I checked around insert edges to make sure epoxy had filled in, one insert required a touch of epoxy to seal a small gap.

The SixTen epoxy is thickened and sets up really hard but is still flexible. Epoxy was used to anchor the studs that windmill blade were attached to, the threaded studs were embedded in only by epoxy (not threaded into steel or anything else!), so for this purpose it should be plenty good.

The original AFS inserts were molded in the fuselage but did not bond to the epoxy because they were not etched/scratched up, if they had been they may not of pulled out from the impact.

I did contact AFS about repairing the inserts, and Julien got back to me with detailed drawings on how to repair the inserts, it required drilling holes through the fuselage and putting the inserts into the topside of the fuselage, so the wing screws pulled the inserts into the fuselage, not out of it. That is how their new foils are made. That required a drill press and removing more material which then had to be replaced with epoxy, so I figured I would try the above method first since it required minimal drilling, and the use of epoxy to hold windmill blade studs in place convinced me it would work for this application where the normal foiling forces drive the wing into the fuselage. Should work as long as the inserts bonded to the epoxy, and the epoxy bonds to the carbon fiber. Talked with West Systems support, they were very knowledgeable and helpful, their website had a link to the story about the windmill studs, pretty interesting.

I did get the inserts in very straight and centered since the inserts all lined up with the wing holes, and the F770 wing required just one layer of clear Gorilla tape on one side of the mounting area to make it perfectly level. But since I never checked the wings for level like this before, I do not know if and/or how much they were out of level before the accident, though the stab. was quite a bit of alignment before the accident, fixed that with a shim.

Took it out today and the foil performed great, and after the session I checked the inserts and they were tight with no cracks or anything else. The blind inserts allow epoxy to stick to the bottom, and that combined with the treatment of the inserts to make the epoxy bind, makes me think the new blind inserts are far stronger than the original through hole inserts. Top pic. is of the repaired fuse. with blind inserts after one session with the F770 wing, Last pic. is of a screw with from the left to right: nut, old insert, and blind insert. In the middle, pic. of the foil in a vise with the bolts attached to the inserts and Duck tape holding them straight.

Note that I did have to trim down the original 20 mm long screws to 16 mm so that they did not bottom out in he blind inserts.

And note that while SixTen epoxy can be put under load after 24 hrs per instructions, it continues to harden. So I did not use the first mixed epoxy that came out of the mixing tip, and after 24 hr it was hard but also flexible, now after 72 hrs it is not nearly as flexible, so it is continuing to harden.

So it is a little tricky getting the wings and stab. all level with each other and the mast. For the wings I need a 48" level to span the wing tips, and the bubble on that level has space between it and the guide lines, so I also stack a 32" level on top of it because the 32" level has no space between the bubble and guide lines. I can use the 32" level on the stab. by its self. Of course everything depends on the mast being perfectly vertical, but hanging a weight along the trailing edge of the mast is very sensitive, just have to be careful not to knock the mast out of alignment. As for the bubble level app., it is only as accurate as the level it is calibrated to. In the end the 32" level was the easiest way to get level. Everything is now dead on level using different thicknesses of tape for the wings, and a plastic shim and tape for the stab.

In an above post I mentioned I had everything to within +/- 0.2 degrees using the bubble level app., but 0.2 degrees is actually a lot to be off when you see how much the wing tip has to move to be level.

Going on a dozen sessions now and inserts are solid, no cracks or anything, have run aground on a sandy bottom at slower speeds too. And no sign of corrosion between the screws and inserts, so everything is A4 like it is supposed to be.