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PostPosted: Mon Aug 29, 2011 5:00 am 
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Location: Chattanooga, TN
Took the Getaway out yesterday for only the 2nd time this summer. Irene provided winds so it was a good day until I started to rig the boat. I noticed that the comp tip and mast had separated leaving about an inch gap. We tried everthing from using the winch to close the gap. Fortunately the strength coach from the UTC Mocs was there and putting the end of the mast against the truck bed and using his strength, he was able to push the comp tip down into the mast. We were able to sail but since I had snapped the halyard cleat earlier trying to pull the 2 together, I had to tie the main halyard to the bottom of the mast which worked for the 3 hours we were out. I now have a new problem. Should I attempt to separate the 2 and reglue or leave it, and why would they seapate. How much of the comp tip in inserted into
the mast.

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PostPosted: Mon Aug 29, 2011 8:12 am 
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There is about 6-8 inches of "bury" into the aluminum. While sailing, the CompTip would not come out. Likely this is from trailering. The tip should be epoxied into the aluminum. The halyard can help hold the two together while trailering. You can add a few rivets at the joint to strengthen the connection if desired. All of the other model masts (but the wave) are riveted together.

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PostPosted: Mon Aug 29, 2011 9:44 am 
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Matt--Thanks for the reply. Would a bolt through the mast assist any in keeping the comp tip in place?

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PostPosted: Mon Aug 29, 2011 11:55 am 
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I would rivet (stainless) before using a bolt.

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PostPosted: Wed Oct 05, 2011 11:14 am 
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I have a little experience with composites. I'm not sure that drilling holes in the composite is a good idea unless the composite was specifically designed for it.

Drilling a hole and loading it with a bolt or rivet will cause very high stress and probably induce cracks in the composite. Usually the manufacturer will lay up a metallic re-enforcement between the layers in preparation for any such holes.

Maybe Hobie can comment on this...

But meanwhile, you won't catch me drilling anything into my $700 comp tip!

I've had my '11 getaway for just over a month. Went sailing this weekend, and as we de-rigged i noticed the comptip had come loose. Since the epoxy is really only under load when the mast is not vertical, probably hobie could put grooves on the comp tip and inside the mast (around the circumference) so that the epoxy will fill these voids and create solid connections.

I'm guessing when we pull out the comp tip, it is covered in cured epoxy but the inside of the mast is fairly clean of epoxy?

The way it currently is, the epoxy probably doesn't bond to the smooth aluminum very well so that when the mast is horizontal on a trailer or being rigged, the bending moment shears the bond. If the epoxy was shaped to interrupt this smooth bond I think it would actually have to shear the epoxy which might hold a lot better than the aluminum-epoxy bond.

Now that i think about it, as a retrofit, maybe putting a wire brush in a drill and plunging it into the aluminum would create enough texture within the aluminum for the epoxy to grip better... I'll have to try that.

Wow, what a mouthful. Sorry! :-)

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PostPosted: Wed Oct 05, 2011 11:24 am 
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Just thinking about this more... It might help to redo the epoxy and keep the aluminum hot (boiler water?) while the epoxy cures. The aluminum will expand, the epoxy will fill the larger gap, then after the epoxy cures the cooler aluminum will contract and form a tighter bond.

Conversely, If you cured your epoxy in the cold the aluminum may expand and pull away from the epoxy/comp tip when the mast is exposed to the sun and warmth.

Makes me reconsider doing the epoxy job in my cold garage!


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PostPosted: Wed Oct 05, 2011 6:36 pm 
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It doesn't change your original assessment that with a shock load the bond between the epoxy on the com tip and the inside of the mast fractures. In our business we have the same problem only with bonding stainless steel and we do have to rough it up some for the epoxy to bond properly.

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PostPosted: Wed Oct 05, 2011 7:00 pm 
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Yeah my thoughts went from grooves to just roughing it up with some coarse grit paper or a wire brush- preferrably a rotary wire brush to make the marks around the inside rather then lines in and out.

DONT TAKE ABRASIVES TO YOUR COMPOSITE TIP!!! This breaks the fibers and seriously weakens the composite!

I also think that heat trick will help out. I believe heat also speeds up the curing time.


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PostPosted: Mon Oct 10, 2011 10:10 am 
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Dude,
You're waaaay overthinking this. Install the comptip as per the manual. Rivets are fine in the comptip if you need them. Every H14/16/18 comptip is installed using rivets and epoxy, and the build is the same for the Get comptip.

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