# Limb flew off !!



## c365 (May 15, 2013)

HOW and why did the limb come off? you have to determine that first, unless the string broke or the limb bolts stripped out.


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## Dacer (Jun 10, 2013)

If your carbon riser is cracked. Its done. It would be unsafe to just shoot some epoxy into it and think its fixed. They form those under high pressure and temp. 

Contact the retailer, probably under warranty. 

Sorry to hear - its always a really disappointment when a piece of equipment fails. Best of luck


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## Bigjono (Apr 21, 2009)

Are the limbs too stiff for the riser? All that torque needs to go somewhere. Hopefully warranty will cover it for you.


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## c365 (May 15, 2013)

Without good, sharp, closeup photos, it's impossible to tell what you mean and how bad. If worse comes to worse for some reason, and if the riser can't be replaced, take it to a carbon bike frame repair guy. LIke with a chair, the worse thing to repair is when the owner tried to repair it themselves, in most cases, making the job far harder.


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## yurmes (Apr 2, 2013)

if you anyway will use epoxy, put over few layers of serving threat. 
I old time we use to fix cracked limbs in this way


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## Kristjon (Feb 19, 2013)

My camera's battery is dead. Will take and post photos tomorrow. Thanks for input.


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## limbwalker (Sep 26, 2003)

Agree you need to know why that happened before you proceed to "fix" anything.


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## normlefebvre (Aug 21, 2010)

I know that The fibrebow risers have had issues with the carbon cracking in the dovetail limb pocket area. Also, UUKHA limbs have a shorter than usual limb fork.

The question is whether the riser already had a crack in it causing the limb to loosen itself from the riser. Or, that the upper limb wasn't inserted all the way in. 

But for a carbon riser to crack around the limb bolt area? Without having seen the pictures, i suspect a defect with the riser.


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## wfocharlie (Feb 16, 2013)

In any resin/fiber lamination, most of the strength comes from the fiber or fabric weave. I that is damaged than adding "glue" will not restore it to its original strength.


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## Warbow (Apr 18, 2006)

wfocharlie said:


> In any resin/fiber lamination, most of the strength comes from the fiber or fabric weave. I that is damaged than adding "glue" will not restore it to its original strength.


Especially given that it's original strength clearly was inadequate to begin with.


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## Bob Furman (May 16, 2012)

Btw, how many turns backed out are you setting your limb bolts. The narrow limb notch combined with the limb bolts being backed way out could cause something like this. I had several limbs pop out while stringing before that were too far backed out.


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## c365 (May 15, 2013)

If it's some defect in the riser, I'd surely call, write the manufacturer, I'm sure they would like to preserve their name in good standing so will probably send you a brand new one. (I would anyway)


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## Kristjon (Feb 19, 2013)

Ok going over it and I think as I was putting my bow together I was distracted and didn't get the "button" under the limb into its pocket. Instead I pbly put it on top of the riser, which would explain why it flew off after the first shot. Here are the pics of my upper limb bolt area. In the one pick I used an allen key to "pry" open the crack a bit more. Thanks for all your input.


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## normlefebvre (Aug 21, 2010)

Clearly, it's a delamination of the carbon fabric of the riser. Probably it went unnoticed with your other limbs. But then, it would have eventually failed.

Don't try to repair, just contact Fiberbow . 

That's to bad, I was hopping you could write a review of your VX1000 limbs.


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## Kristjon (Feb 19, 2013)

So Normlefebvre, you don't think that maybe the crack was caused by me putting the limb on top of the dove tail and then shooting it, there by crushing it down when I shot?


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## Dacer (Jun 10, 2013)

Hopefully you can get it repaired or replaced - not sure what a company policy will be on user error incurred damage. best of luck


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## DomKingsboroBow (Jan 10, 2015)

Are you sure this is not a BOWTECH bow? Have to ask...


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## normlefebvre (Aug 21, 2010)

I think delamination cause by a weakness in the riser + repetitive shots is the probable cause. If that area of the riser is slightly deprived of epoxy resin + the configuration of the carbon fabric than you have delam. Check-out these Fibrebow risers.
http://img-2011-12.tapatalk.com/d/12/12/16/azava3ej.jpg
http://img-2011-12.tapatalk.com/d/12/12/16/gu7u2u4u.jpg
http://img-2011-12.tapatalk.com/d/12/12/16/ejy3eru6.jpg

Don't forget that UUKHA limbs have shorter limb notch under the tiller bolt. So, if the dovetail shifted ever so slightly during the shot, than probably the limb would fly out of the riser. 

UUKHA have a similar all carbon riser but they decided to have all metal limb attachement system which is more reliable.
http://www.uukha.com/archive/img/prod-uproLite-3.png


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## c365 (May 15, 2013)

normlefebvre said:


> I think delamination cause by a weakness in the riser + repetitive shots is the probable cause. If that area of the riser is slightly deprived of epoxy resin + the configuration of the carbon fabric than you have delam. Check-out these Fibrebow risers.
> http://img-2011-12.tapatalk.com/d/12/12/16/azava3ej.jpg
> 
> http://img-2011-12.tapatalk.com/d/12/12/16/ejy3eru6.jpg
> ...


Those photos look just like the OP's riser. Yeah, I was surprised to see the dovetail slot is all carbon. I would have imagined a metal insert.


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## tim2970 (Jan 10, 2010)

Ouch....sorry to here that happened


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## hooktonboy (Nov 21, 2007)

Kristjon said:


> So Normlefebvre, you don't think that maybe the crack was caused by me putting the limb on top of the dove tail and then shooting it, there by crushing it down when I shot?


I do remember that because of the way the pocket is manufactured / shaped - it is possible to do that accidentally on the FB. Did it myself a couple of times but noticed before actually taking a shot. I can imagine that shooting it with the limb fitted that way could crush the thin edges  Looking at the first pic you can see the shape of the metal dovetail over the U section, so I expect you've identified the cause of the failure. Very unlucky.

Bad news, however it happened.


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## Kristjon (Feb 19, 2013)

well I did some shooting with it yesterday, 60 arrow no pblms. If I can find a bike shop that does epoxy repair you think it will help?


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## normlefebvre (Aug 21, 2010)

Did you use your UUKHA VX1000?


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## Kristjon (Feb 19, 2013)

Yes shot yesterday and today with them. Limbs are good no damage besides chipped top coat.


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## normlefebvre (Aug 21, 2010)

That's good news. It was after all, probably the limb dovetail that wasn't inserted in it's channel then.

As for the carbon repair, I would be tempted to repair it myself by gently prying open the crack and then use a small slow setting epoxy syringe. Put a plastic sheet and a C clamp on the top layer. Monitor it after. But if you can find a repair shop, sure.

But first I'd would contact Fiberbow. 

Good luck and good shooting!


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## Kristjon (Feb 19, 2013)

Well I emailed Fiberbow, got a reply to say try and fix it myself. So after exhausting searching in my city and getting some wrong info, ( fiberglass resin is not as good as epoxy) and miss leading web info from Canadian Tire, I finally found 30 min Slow Cure epoxy at a model airplane shop. It fully cured in 24hrs, so I found small syringe to push the epoxy into the small area and used a clamp to squeeze it together till it tried fully.

Just came back from the range and after 90 arrows, it hasn't split yet. Question, after sanded off some excess epoxy its duller than my riser finish can I use some nail polish or lacquer and touch it up?


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## drstack (Feb 9, 2011)

Good Morning Kristjon;

While epoxies are pretty impervious to solvents once set, I would be cautious about applying anything on top of it along the lines of lacquer. Looking at the photos you posted previously, it does not appear the riser has a high gloss finish to it, more of a matte.

Don't know what grade of sandpaper you used to remove the excess epoxy, but you may be able to go to progressively finer grits and effectively 'polish' the epoxy until it is the same as the manufacturer's finish.

regards,
Dave


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## PaulME (Jun 11, 2014)

In general epoxy is not UV stable, it will discolor and get brittle if left in the sun. Check out some of the info on strip built kayaks and canoes, top coating over the epoxy is standard. There is an epoxy test on oceankayaks.com and likely others. I would not hesitate to coat the repair, uv is probably not much of an issue in that spot as it should be mostly covered by the limb. if your worried about the finish of course the sanded area will be dull it's got thousands of tiny scratches. Depending on the original finish you can go with progressively finer sanding up to about 2000 grit then switch to compound - all available at a supplier that sells automotive paint. I'd just get it in the ballpark and then shoot it, shiny equipment is no more accurate than cosmetically scratched and chipped.

Paul


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