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Carbon Boom Breakage.
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keycocker



Joined: 10 Jul 2005
Posts: 3385

PostPosted: Wed Sep 04, 2013 2:10 am    Post subject: Reply with quote

Thanks for the info. Who might that other guy with a good success rate be?
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swchandler



Joined: 08 Nov 1993
Posts: 5830

PostPosted: Wed Sep 04, 2013 3:55 am    Post subject: Reply with quote

If I were to guess, it would be Mike Zajicek. But he is a very busy guy, so I seriously doubt that he would take on such work. Far too many windsurf and kite boards to make.
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bamer



Joined: 30 Sep 2014
Posts: 58

PostPosted: Wed Sep 04, 2013 12:08 pm    Post subject: Reply with quote

swchandler is correct. It is Mike Z and he is too busy to do it unless there has been some big change in the last few months.

BTW, Mike Z has also had success fixing masts. Some failed, but many/ most have held and he was able to replicate bend. But Mike is a magician.
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keycocker



Joined: 10 Jul 2005
Posts: 3385

PostPosted: Wed Sep 04, 2013 2:20 pm    Post subject: Reply with quote

Thanks for the lead. I will try him.
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bamer



Joined: 30 Sep 2014
Posts: 58

PostPosted: Wed Sep 04, 2013 4:02 pm    Post subject: Reply with quote

If you want to outsource it, I would try Roberts Composites or anyone that does carbon frame repair on bikes. They would only need to slightly adapt their process and would likely be stoked to not have to worry about cosmetics (because the repairs are almost always hidden under boom grip). Then just regrip the area yourself.

Calfee claims to have fixed over 8000 carbon frames or parts. Yet I bet if you polled cyclists, a majority would tell you that once a carbon frame is cracked it needs to be replaced because it will never be safe again (i.e. repair is not an option). You have to just throw a $2,000 frame in the garbage! Total nonsense! A primary feature of carbon/ composite construction is how easy it is to repair.

http://calfeedesign.com/repair/

http://www.carbonframerepair.com/

http://www.robertscomposites.com/
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keycocker



Joined: 10 Jul 2005
Posts: 3385

PostPosted: Thu Sep 05, 2013 5:50 pm    Post subject: Reply with quote

Of course A bike not the same as, say, a mast. You don't usually risk drowning, and the margins are less with a mast. I have had race masts break while carrying them rigged because they got a tiny scratch going sideways. A bike frame or boat spar won't collapse while carrying it from a tiny mark.

That is why mast repairs that only work sometimes are exactly the same as those that always fail.
Repared masts can get you killed.
Thanks for the links.
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whitevan01



Joined: 29 Jun 2007
Posts: 489

PostPosted: Thu Sep 05, 2013 7:46 pm    Post subject: Reply with quote

the best way to avoid carbon failures is not to impact it. any kind of impact of carbon against a hard surface can cause internal cracks that aren't visible on the outside. A surface scratch can come from such an impact and can be a sign that there is something wrong inside the carbon structure.


and, yes, failure of a carbon tube on a bike can cause death. suppose one is doing 30+ mph down a hill on pavement and the top tube fails. I think there would be a good chance of a catastrophic result in that case.
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GURGLETROUSERS



Joined: 30 Dec 2009
Posts: 1354

PostPosted: Fri Sep 06, 2013 3:42 am    Post subject: Reply with quote

Still in two minds about carbon. Have gone back to a couple of new alloy booms. Carbon may be wonderful if properly built, but it doesn't give any warning of imminent failure. Bang, and it's gone!

As carbon man (sorry, Whitevan man Wink ) says about bikes, the ground is hard, even at 30 m.p.h. downhill. Methinks I'll stick with alloy there too.

There was a video doing trhe rounds a while ago of a mountain bike hard man attempting to 'crack' 100 m.p.h. down a long steep mountain side. Just as he hit the magic ton (radar gun) his front tele forks snapped. (He survived, but was badly injured.)

Also, while in the mad vein, three playboat whitewater kayakers shot a long steep twisty dam spillway, and were 'clocked' at 56 m.p.h. They survived - but were arrested!

As for F 1, boring (sorry sir Laughing ) except when Kimi gets upset, and tells his excitable pit crew to shut their cake holes! (Got to like that!)
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keycocker



Joined: 10 Jul 2005
Posts: 3385

PostPosted: Fri Sep 06, 2013 3:05 pm    Post subject: Reply with quote

Of those links kindly provided, only Roberts agreed to consider a repair.
One outfit said it would cost more than wholesale on a new boom, which runs from about $480 to 550.
I guess that is a right price range for a repair on a $2000 bike frame.
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bamer



Joined: 30 Sep 2014
Posts: 58

PostPosted: Fri Sep 06, 2013 7:30 pm    Post subject: Reply with quote

keycocker wrote:
Of course A bike not the same as, say, a mast. You don't usually risk drowning, and the margins are less with a mast. I have had race masts break while carrying them rigged because they got a tiny scratch going sideways. A bike frame or boat spar won't collapse while carrying it from a tiny mark.


While a bike frame is unlikely to fail from carrying it, a bike failing underway is much more dangerous than what we deal with. Most windsurfers' anecdotal experiences on bikes, daily happenings in emergency rooms, and national/ international statistics would back this up.

Having raced windsurfing for >10 years, I would go so far as to say that a broken mast or boom is not dangerous in the vast majority of situations. The danger is associated with what breakdowns can cause: lack of mobility in a dangerous sailing area (i.e. exposure, drifting out to sea, drifting into a sketchy area).

I fully appreciate the real danger or perception of danger which may lead to overexertion and/ or cause a string of bad decisions that may result from any breakdown. This is a primary reason why I will not post directions for fixing a boom. Where most people sail is safe when they can move with impunity at 20-30+ mph or even slog at at 4 mph. Take away either of these options and the outlook can change in a hurry.

This may be the same danger that 'can get you killed' that you are eluding to. I hope we are not talking about people getting impaled or rolled up into some kind of scary splintery sea burrito.

Also, I don't want to be argumentative and didactic, but a mast will not break from a scratch or tiny mark. In the absence of taking an ultrasound, the scratch may just be an indication of broken fibers in this location.

Masts primarily break from being overloaded (including point and compression loading), impact damage, or from heat deflection related failures. For race masts a large percentage of breaks are related to heat deflection. In these cases the mast gets hot as the rig is sitting on the beach (grass, leaning up against a tree, etc.), the epoxy matrix starts to soften, and the wall loses adequate structural integrity so it buckles. A thin walled, high carbon content mast is more susceptible because of the ratio of surface area to wall thickness.

The heat deflection danger goes away when the rig hits the water or you start sailing because of the water/ air cooling coupled with the change in angle of incidence for the sun.

Carrying gear is one of the more common times for a heat deflection failure because you quickly introduce an extra force onto the rig in the form of gravity (which is dispersed when sitting on the ground). The worst scenario can be when a mast is nice and hot, to flip the rig over so the hot side is now the compression side, connect the board, and then start your carry with some bounce in your step.

I'm sure I sound like a total didactic dick for telling you what likely happened with your masts. But this is infinitely more likely than only a scratch causing a break. Every race mast that goes into a cambered sail has scratches from the cambers and yet breakages at the cambers are not all that common. No manufacturer to my knowledge has ever tried to alleviate surface scratching, which could be done by simply adding aluminum powder to the gel coat, but many have and continue to use white, gold, or silver finishes that reflect light/ heat.

Heat defection occurs well below 150 degree Fahrenheit on most of composites we use.

Back to my last post: The point of the links was to show there are people that repair carbon tubes; thousands of tubes where the stakes are high. Having fixed both carbon booms and bikes, I can tell you bikes are much more difficult to work on.

I am not an engineer, but these repairs involve basic engineering concepts that are fairly easy to work through and composite techniques many already know. From what I have seen there are a lot more engineers in the bike industry than in the windsurf industry. This is why a guy/ woman from the bike industry may be easily able to step over and fix booms but an expert board builder may not (reference to your earlier post). This is an engineering problem and an engineering degree is generally more portable in solving different problems than empirically derived expertise in one area.

Below is a picture of an aluminum frame I cut up and spliced in carbon tubes. The top tube, seat tube, and seat stays now have carbon bridges. The idea is to force the vibrations through the carbon for less rider fatigue. The bike has about 5,000 miles on it and is one of my favorite road bikes.

The bike is currently a few feet away from both my Pryde X9 Formula booms. Both were repaired after breaking: one ~6 years ago the other ~8 years ago. Each boom has a minimum of 5,000 miles (one should be
closer to 12,000 miles). The booms work great, have had zero problems since, and are both substantially lighter than an equivalent Maui Sails boom. I could post a picture of the booms, but they just look like ordinary booms.

BTW while using these items I have weighed between 210 and 240 pounds. I am 220 now for those keeping tabs. About 70% of my sailing is done on an 11.0 in conditions from 15-25mph. So the booms have been loaded once or twice; )

As before, I do not advocate fixing masts.



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