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CA fin repair strong enough?

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Mr G

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After falling flat from a mile high with only a parachute still wrapped in a burrito, one Vulcanite fin took the brunt of the impact bending at the root about 15 degrees. The wood failed along the grain but did not separate. The first thought was to wiggle the fin back and forth until it broke of and then epoxy it back together. On second thought, with all the fibers sticking up, the chance of getting a good fit was considered minimal. So, on a whim, I decided to just inject thin CA glue into the seam on both sides. The thought was that the CA would wick up into the voids between the separations in the grain creating a strong bond.
IMG_7135.jpg IMG_7136.jpg
I will likely test fly the repaired Vulcanite on a G motor to keep forces low but would like to take full advantage of the 38mm motor mount if the fin will hold up. Does anyone have experience with how strong a 1/8 inch birch ply fin is after being CA'd like this?

More info on the Vulcanite build can be found in this thread: http://www.rocketryforum.com/showth...-Partizon-build-challenge&highlight=vulcanite
 

tab28682

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I predict that a repair using thin CA that is fully wicked into the damaged wood fibers will make the fin effectively as strong as it ever was. I would go back to flying the same motors as always in the Vulcanite.

It might end up being a touch more brittle and if it takes another similar impact, it might crack worse than the first time, but that would be a future problem. If t did crack again, I would effect a fiberglass repair for that fin joint.
 

ksaves2

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As long as it's not punched hard with a very powerful motor, you won't have to worry about fin flutter. It should work. Kurt
 

Salvage-1

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A couple of weekends ago at NXRS, I had a rocket fall and do roughly the same damage as I see on yours. Mine bust a crack the whole length of one of the fillets, I couldnt see if there was any damage to the wood.
One of the TAP's that was hanging around our camp shouted for the CA and told me to do exactly what you did.
Next day I flew it on an L265. I have difficulty now trying to find where that crack was.

Hope yours works as well, no reason it shouldnt.
 

Mr G

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Thanks all for the input. After letting things cure, it feels tight. Nice to know others have had positive experiences. Gives me some confidence to fly it again.
 
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