Select to expand quoteFreeflight said..FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1
Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?
Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
In the case of this fuselage repair I'd still be inclined to go with Chicago bolts. Much stronger allow you to reinforce the area more completely.
Select to expand quoteGrantmac said..Freeflight said..FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1
Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?
Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
In the case of this fuselage repair I'd still be inclined to go with Chicago bolts. Much stronger allow you to reinforce the area more completely.
Grantmac, thanks for the feedback, I appreciate it. But drilling 3 holes through the fuselage, with all 3 aligned exactly perpendicular to the fuselage is a little much for my workshop. And I just do not like the idea of weakening the fuselage with the through holes.
But I am now thinking of peeling back the thin partially erupted carbon twill layer covering the top edge of the inserts, and then pull out the now loose inserts, then add epoxy on the outside of the inserts and the inside of the cavity, and then press the inserts back into the fuselage as I described above in step 3. That would insure the inserts were epoxied in about as good as originally. Then use epoxy to seal the carbon twill back down over the top edges of the inserts. But that is for mostly cosmetic reasons, the outside wall of the insert contacting the fuselage is what is going to keep the insert in place, much greater surface area than the 1/8" top edge of the insert.
Select to expand quoteGrantmac said..Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
You don't miss an opportunity to knock Slingshot, do you? So tedious.
FWIW - in our group of 30+ SS Hoverglide Frothers (collectively 100,000km+ on foil), I don't know of a single case of the threads in the aluminum fuselage failing.
so I decided to pull out one threaded insert from the fuselage, it is a tappex insert, see pic., has the distinctive tappex cutting edge (see upper left side). So these inserts were not epoxied in, but just screwed in. Not much to hold a big wing. Maybe go to an 8 mm tappex or similar style screw in threaded insert, but then wing holes will have to be drilled out a little. It would have been nice if someone from AFS would have told me beforehand what the insert was and how it was inserted. Last I heard, Julien want to do a video conference to explain how to repair it, and said okay I have Facetime, and then no response. So they screwed it in and then covered the collar with carbon twill. The threads seem shallow for what they have to hold.
McMaster has SS inserts, the 8 mm needs a 12 mm hole that is 16 mm deep, have the depth with the existing hole. 12 mm, or 1/2", diameter seems large but there is room in the fuselage for it.
Any thoughts on going with 8 mm inserts and screws? Lucky I did not try to epoxy the 6 mm insert back in like I said I would, because when the inserts got pulled out that small amount the grooves for the outside threads got degraded, and epoxy would have a hard time coming up from the inside even with a screw trying to force it upward. Probably would have ended up losing a wing in-flight.
Select to expand quoteGrantmac said..Freeflight said..FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1
Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?
Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
Not sure about that. Pretty certain my moses fuse is taped straight into the aluminium. I don't know why you would put inserts into a aluminium
Select to expand quotethedoor said..Grantmac said..Freeflight said..FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1
Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?
Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
Not sure about that. Pretty certain my moses fuse is taped straight into the aluminium. I don't know why you would put inserts into a aluminium
Hey guys, can we stay on topic, please! Topic is carbon fuselage with tappex inserts that partially stripped the grooves they cut in the carbon fuselage. Go to 8 mm inserts?
Select to expand quoteSandman1221 said..thedoor said..Grantmac said..Freeflight said..FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1
Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?
Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
Not sure about that. Pretty certain my moses fuse is taped straight into the aluminium. I don't know why you would put inserts into a aluminium
Hey guys, can we stay on topic, please! Topic is carbon fuselage with tappex inserts that partially stripped the grooves they cut in the carbon fuselage. Go to 8 mm inserts?
haha sure. I feel your pain bro...nothing worse than not being able to foil.
Before going to 8mm I would probably mix up some epoxy and filler and reinsert them.
You will need to set up some kind of jig to make sure they stay in the right position as it hardens.
Select to expand quotethedoor said..Sandman1221 said..thedoor said..Grantmac said..Freeflight said..FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1
Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?
Most decent alloy fuselages come with inserts? Only the really poorly built ones like Slingshot thread right into the aluminum from what I've seen.
Not sure about that. Pretty certain my moses fuse is taped straight into the aluminium. I don't know why you would put inserts into a aluminium
Hey guys, can we stay on topic, please! Topic is carbon fuselage with tappex inserts that partially stripped the grooves they cut in the carbon fuselage. Go to 8 mm inserts?
haha sure. I feel your pain bro...nothing worse than not being able to foil.
Before going to 8mm I would probably mix up some epoxy and filler and reinsert them.
You will need to set up some kind of jig to make sure they stay in the right position as it hardens.
Thanks thedoor, what kind of filler? If I use the 6 mm McMaster hardwood tapping inserts, they will have plenty to cut into, can add epoxy and filler, and just mount wing and use that as an alignment jig since they will already be set from the cutting threads.
And I was looking at 6 mm and 8 mm inserts with deeper cutting threads than the tappex, the 6 mm from McMaster takes a 25/64" hole, while 8 mm takes 32/64" hole. The 6 mm would get a decent bite in the hole left by the tappex 6 mm because the tappex cutting threads are not as deep.
Okay, the new plan is to gently work out the other two tappex inserts, and screw the 6 mm McMaster hardwood 18-8 SS inserts into the same hole, without drilling it larger. Can apply epoxy with filler to the holes and insert, to fill in any gaps as the inserts cuts a new groove. Am I missing something?! this seems very straight forward. No drilling bigger holes in fuselage or wing. And the install bit is only $10, each insert is 3.50, so $22 plus shipping to repair the fuselage.
Select to expand quoteSandman1221 said..Thanks thedoor, what kind of filler? If I use the 6 mm McMaster hardwood tapping inserts, they will have plenty to cut into, can add epoxy and filler, and just mount wing and use that as an alignment jig since they will already be set from the cutting threads.
And I was looking at 6 mm and 8 mm inserts with deeper cutting threads than the tappex, the 6 mm from McMaster takes a 25/64" hole, while 8 mm takes 32/64" hole. The 6 mm would get a decent bite in the hole left by the tappex 6 mm because the tappex cutting threads are not as deep.
I'd try and just pour in epoxy - if a filler is needed I'd use Cabosil Silica filler - not micro balloons.
Your initial repair ideas seem good and I'd follow Subsonic's advice to epoxy multiple layers of carbon cloth over the insert.
Then I'd give it a go in shallow, clear water and see how it holds up.
Probably be fine - you said it was an only an unusual catastrophic event that broke in the first place 
Select to expand quoteazymuth said..Sandman1221 said..Thanks thedoor, what kind of filler? If I use the 6 mm McMaster hardwood tapping inserts, they will have plenty to cut into, can add epoxy and filler, and just mount wing and use that as an alignment jig since they will already be set from the cutting threads.
And I was looking at 6 mm and 8 mm inserts with deeper cutting threads than the tappex, the 6 mm from McMaster takes a 25/64" hole, while 8 mm takes 32/64" hole. The 6 mm would get a decent bite in the hole left by the tappex 6 mm because the tappex cutting threads are not as deep.
I'd try and just pour in epoxy - if a filler is needed I'd use Cabosil Silica filler - not micro balloons.
Your initial repair ideas seem good and I'd follow Subsonic's advice to epoxy multiple layers of carbon cloth over the insert.
Then I'd give it a go in shallow, clear water and see how it holds up.
Probably be fine - you said it was an only an unusual catastrophic event that broke in the first place
Thank you azymuth!, the only issue I see with putting multiple layers of carbon cloth over the inserts is it could affect how the wing seats on the fuselage, do not want to mess that up since it affects how the front wing is aligned with the rear stabilizer.
Oh, and it seems worth buying an$80 table top drill press "with a drill vise" to hold the fuselage, to make sure the inserts go in straight, what do you think? Only get one chance per insert to get it right!
I'd still put cloth over all the inserts - it won't change the angle of the wing on the fuselage.
Check first by adding an equivalent thickness of gaffa-tape, that the wing stills fits the fuse curve properly.
Once the cloth is on drill minimum size holes to fit the screws.
I wouldn't worry if the front wing ends up being 3mm lower than it was - the angle to the rear wing will be the same.
Yes, buy a drill press - I bought one when I installed the Helicoils on my fuses, worth getting it straight.
The AFS dealer manual did not explain how to change the inserts but it is old and as I mentioned the new AFS foils are made with the ability to do such repairs more easily.
The new foils have the holes going right through the fuselage and then the top of the holes are filled. The idea being that if the inserts need replaced they are replaced from ABOVE.
Select to expand quoteSailrepair said..
The AFS dealer manual did not explain how to change the inserts but it is old and as I mentioned the new AFS foils are made with the ability to do such repairs more easily.
The new foils have the holes going right through the fuselage and then the top of the holes are filled. The idea being that if the inserts need replaced they are replaced from ABOVE.
Interesting, thank you Sailrepair. Julien from AFS asked me to take a picture of the top of the fuselage above the inserts, maybe he wanted to check to see if there were filled in holes there like on the newer versions? And once he saw they were no filled in holes he decided not to talk with me?
Select to expand quoteFreeflight said..
Maybe get the price for the replacement fuse before spending any money
Cheers
Rod
Freeflight, The fuselage is connected to the mast, one piece all carbon, 950 euro for the 85 cm version plus shipping, probably 120 euro, so around 1100 euro and I am stuck with the 85 cm mast/T-bar since my F-series wings will not fit the new 95 cm mast/T-bar. $22 in new inserts seems a bargin!
Select to expand quoteazymuth said..
I'd still put cloth over all the inserts - it won't change the angle of the wing on the fuselage.
Check first by adding an equivalent thickness of gaffa-tape, that the wing stills fits the fuse curve properly.
Once the cloth is on drill minimum size holes to fit the screws.
I wouldn't worry if the front wing ends up being 3mm lower than it was - the angle to the rear wing will be the same.
Yes, buy a drill press - I bought one when I installed the Helicoils on my fuses, worth getting it straight.
Okay azymuth, thank you, will get the new inserts installed and then check about adding cloth over them.
looks like only place I can get self tapping A4 SS inserts is from the UK. Good news is I found some that have a larger external thread diameter so the existing holes do not need to be enlarged!, they will screw right in. So drill press is not needed.
Select to expand quoteSandman1221 said..Freeflight said..
Maybe get the price for the replacement fuse before spending any money
Cheers
Rod
Freeflight, The fuselage is connected to the mast, one piece all carbon, 950 euro for the 85 cm version plus shipping, probably 120 euro, so around 1100 euro and I am stuck with the 85 cm mast/T-bar since my F-series wings will not fit the new 95 cm mast/T-bar. $22 in new inserts seems a bargin!
Oh that makes sense. If you don't switch front wings. And if this expoxying of the inserts does not work, then I would just epoxy the wing to the fuse and hope I can fit it in my car all connected
Select to expand quoteSandman1221 said..Sailrepair said..
The AFS dealer manual did not explain how to change the inserts but it is old and as I mentioned the new AFS foils are made with the ability to do such repairs more easily.
The new foils have the holes going right through the fuselage and then the top of the holes are filled. The idea being that if the inserts need replaced they are replaced from ABOVE.
Interesting, thank you Sailrepair. Julien from AFS asked me to take a picture of the top of the fuselage above the inserts, maybe he wanted to check to see if there were filled in holes there like on the newer versions? And once he saw they were no filled in holes he decided not to talk with me?
They might be busy at the Defi.
One good-news thing about this is that the front wing PUSHES against the fuselage when in flight. This means that the inserts and screws need to mostly just hold the wing against the fuselage, but not carry any lifting force. Not much tension on the screws and inserts. Yes, of course, there will be some left/right rocking tension on the screws, but that is not nearly as forceful as lift. (Unless, of course, a beach flight slams the foil around in all sorts of unplanned ways.)
The stab, on the other hand, PULLS against the fuselage in the AFS and Moses (and some others). The stab screws do indeed carry lifting force, but since it is relatively small, tension on the screws and inserts for the stab is not as critical.
The repair ideas here look really good. Good enough for the front wing. Thanks for the discussion.
Select to expand quotethedoor said..Sandman1221 said..Freeflight said..
Maybe get the price for the replacement fuse before spending any money
Cheers
Rod
Freeflight, The fuselage is connected to the mast, one piece all carbon, 950 euro for the 85 cm version plus shipping, probably 120 euro, so around 1100 euro and I am stuck with the 85 cm mast/T-bar since my F-series wings will not fit the new 95 cm mast/T-bar. $22 in new inserts seems a bargin!
Oh that makes sense. If you don't switch front wings. And if this expoxying of the inserts does not work, then I would just epoxy the wing to the fuse and hope I can fit it in my car all connected
Thedoor, the new 6 mm inserts have a larger OD and are also longer, and so will screw into the fuselage holes from the pulled out old inserts, so should be good. Not going to epoxy wing in, I switch them too often!, but I can fit the fully assembled foil into my car.
Select to expand quotesegler said..
One good-news thing about this is that the front wing PUSHES against the fuselage when in flight. This means that the inserts and screws need to mostly just hold the wing against the fuselage, but not carry any lifting force. Not much tension on the screws and inserts. Yes, of course, there will be some left/right rocking tension on the screws, but that is not nearly as forceful as lift. (Unless, of course, a beach flight slams the foil around in all sorts of unplanned ways.)
The stab, on the other hand, PULLS against the fuselage in the AFS and Moses (and some others). The stab screws do indeed carry lifting force, but since it is relatively small, tension on the screws and inserts for the stab is not as critical.
The repair ideas here look really good. Good enough for the front wing. Thanks for the discussion.
Thanks Segler, not sure why no one from AFS suggested this approach, i.e., use M6 inserts that are larger in OD and longer too, both will help keep the wing on.
Chicago bolts will be stronger in every way because of how they distribute force (pulling the fuselage together instead of relying on a weak mechanical bond to the core material) and they are actually smaller outside diameter than all these inserts which will allow adding material to properly locate them. Any "peeling back" of the fuse skin is a recipe for disaster since that is literally where all the strength is, the core just holds it apart and you'll never get that adhesion back since epoxy doesn't chemically bond to previously cured epoxy.
I think any solution is likely to fail but the Chicago bolts will be the least likely. But it's your foil and you will do what you want. I just build custom fuselages and repair boards for fun so what do I know.
Lack of any inserts is a major shortcoming in foil design. Not going with a cross-bolt in the fuselage/mast connection is another (as Armstrong found out). Manufacturers who spend significantly more money developing their equipment then promoting it seem to have this figured out.
Select to expand quoteGrantmac said..
Chicago bolts will be stronger in every way because of how they distribute force (pulling the fuselage together instead of relying on a weak mechanical bond to the core material) and they are actually smaller outside diameter than all these inserts which will allow adding material to properly locate them. Any "peeling back" of the fuse skin is a recipe for disaster since that is literally where all the strength is, the core just holds it apart and you'll never get that adhesion back since epoxy doesn't chemically bond to previously cured epoxy.
I think any solution is likely to fail but the Chicago bolts will be the least likely. But it's your foil and you will do what you want. I just build custom fuselages and repair boards for fun so what do I know.
Lack of any inserts is a major shortcoming in foil design. Not going with a cross-bolt in the fuselage/mast connection is another (as Armstrong found out). Manufacturers who spend significantly more money developing their equipment then promoting it seem to have this figured out.
Thanks Grantmac, you could be right about the Chicago bolts, but I just do not want to try installing them, too many things I could screw up! Bigger in OD and longer inserts should be better than the originals, and the original inserts took many hard hits and were fine, just having the board/foil flying in the air and then landing on one wing tip on hard packed sand was just too much for them. With Chicago bolts that same impact could of broken the fuselage, and that would of been the end of it. Looking at the original inserts I am amazed they held up they way they did. I think overall the AFS design is good, and that is why I am sticking with inserts. I mean that was a catastrophic impact, and nothing was broken!, yes the inserts pulled out but the wing, stabilizer, and foil are all good.
Select to expand quoteSandman1221 said..Grantmac said..
Chicago bolts will be stronger in every way because of how they distribute force (pulling the fuselage together instead of relying on a weak mechanical bond to the core material) and they are actually smaller outside diameter than all these inserts which will allow adding material to properly locate them. Any "peeling back" of the fuse skin is a recipe for disaster since that is literally where all the strength is, the core just holds it apart and you'll never get that adhesion back since epoxy doesn't chemically bond to previously cured epoxy.
I think any solution is likely to fail but the Chicago bolts will be the least likely. But it's your foil and you will do what you want. I just build custom fuselages and repair boards for fun so what do I know.
Lack of any inserts is a major shortcoming in foil design. Not going with a cross-bolt in the fuselage/mast connection is another (as Armstrong found out). Manufacturers who spend significantly more money developing their equipment then promoting it seem to have this figured out.
Thanks Grantmac, you could be right about the Chicago bolts, but I just do not want to try installing them, too many things I could screw up! Bigger in OD and longer inserts should be better than the originals, and the original inserts took many hard hits and were fine, just having the board/foil flying in the air and then landing on one wing tip on hard packed sand was just too much for them. With Chicago bolts that same impact could of broken the fuselage, and that would of been the end of it. Looking at the original inserts I am amazed they held up they way they did. I think overall the AFS design is good, and that is why I am sticking with inserts.
Drilling it out and using some kind of bolt does sound like a better back up plan than epoxying the wing on. 
If the original inserts have partially pulled out, then the bond between the insert and the fuse is compromised. I would think that they then need to be fully removed and replaced. The Chicago bolts are a sound alternative. Replacing the fuse is another.
Trying to push the insert back into position and reuse is a band-aid fix
Understand the reluctance to drill through the fuse, but with a proper jig (you can make one out of clay) and a drill press the process is very simple. I would then install helicoils on the far side of the fuse, to receive the bolts. The advantage of this is that the helicoil is being pulled into rather than out of the fuse as you torque each bolt.
I do suspect you're going to eventually have to acquire a new fuse, expensive though it is. The risk of having the front wing come off four miles out would frighten me to death, I'd ride more cautiously and as we all know - that's when the trouble really starts....
Select to expand quoteAwalkspoiled said..
Understand the reluctance to drill through the fuse, but with a proper jig (you can make one out of clay) and a drill press the process is very simple. I would then install helicoils on the far side of the fuse, to receive the bolts. The advantage of this is that the helicoil is being pulled into rather than out of the fuse as you torque each bolt.
I do suspect you're going to eventually have to acquire a new fuse, expensive though it is. The risk of having the front wing come off four miles out would frighten me to death, I'd ride more cautiously and as we all know - that's when the trouble really starts....
Awaikspoiled, thanks for the information, I will keep that in mind since as you point out it is a very strong attachment, my only concern is the fuselage was not designed with that in mind, like the new ones are. I ordered the A4 SS replacement tapping inserts, since they are larger in OD with deeper cutting threads and longer, they will cut new grooves into the fuselage, just like the originals ones. Installing them with epoxy will make a stronger bond than the original inserts which from what I can tell did not have epoxy put on them during installation, that combined with rather shallow cutting grooves made for a weaker bond.
Select to expand quoteJohn340 said..
If the original inserts have partially pulled out, then the bond between the insert and the fuse is compromised. I would think that they then need to be fully removed and replaced. The Chicago bolts are a sound alternative. Replacing the fuse is another.
Trying to push the insert back into position and reuse is a band-aid fix
John340, I agree with you, just ordered larger OD and longer M6 tapping inserts, so they will cut new grooves during installation into the old holes, that along with adding epoxy on the insert should make for a stronger attachment than the original ones which were not epoxied during installation from what I can tell, though the original ones all the same took a lot of high speed impacts.
Select to expand quoteJohn340 said..
If the original inserts have partially pulled out, then the bond between the insert and the fuse is compromised. I would think that they then need to be fully removed and replaced. The Chicago bolts are a sound alternative. Replacing the fuse is another.
Trying to push the insert back into position and reuse is a band-aid fix
I agree with this statement
John 340, that's a great seabreeze Avatar image of you blazing on the foil 
Love to get a shot of myself looking that good one day
