# JB Weld on Carbon Fiber?



## fleetseat (May 1, 2008)

So, I found a crack in the seat post tube of my '06 Tarmac Expert and I'm wondering if using JB Weld on it would work. Since I'm not the original owner, the warranty thing is out the window. I've searched and found topics on using it (or trying it) on aluminum and/or steel frames for some repairs, but nothing on CF. Anyone have experience with this, or am I just wishful thinking here?


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## PlatyPius (Feb 1, 2009)

wishful thinking.


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## been200mph (May 28, 2004)

Skip the JB Weld. Maybe skip anything until you post some pics/info on where the crack is at. If it's in a home-fixable location you can get some carbon fiber cloth and resin/hardener. Grind the area and sand to prep for a repair. Put a few layers of cloth/resin on there and try to roll or press out as much resin as possible so the cloth layers are tightly compressed over the repair area. Then let it cure and sand the area smooth and at least clearcoat it. But... if it's in a highly stressed location I'd leave any repairs up to a place that does it all the time such as Calfee/etc.


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## heffergm (Jul 9, 2010)

Every time I hear JB weld I think '73 camaro.... 

Trust me, skip the JB weld.


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## fleetseat (May 1, 2008)

Thanks for the advice everyone. Since this is in a high-stress area, it looks like a new frame is in my future.


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## frdfandc (Nov 27, 2007)

heffergm said:


> Every time I hear JB weld I think '73 camaro....



...........and a mullet


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## JoelS (Aug 25, 2008)

E-mail that picture to Calfee and see if they're able to repair it. Cheaper than a new frame.


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## rward325 (Sep 22, 2008)

Are you the original owner of the frame? Do you have receipts for the bike? Pretty sure Specialized is lifetime warranty on the frame for original purchaser.


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## marktomin (Sep 22, 2008)

rward325 said:


> Are you the original owner of the frame? Do you have receipts for the bike? Pretty sure Specialized is lifetime warranty on the frame for original purchaser.


read the op


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## rward325 (Sep 22, 2008)

Since no to my above send the pics to Calfee and see if they will touch it. I have seen some amazing work come out of their shop.


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## wassler (Oct 25, 2009)

Do you know the original owner? ( as in being a friend) Maybe he wants to help you with the warranty claim. 

cheers,

Wassler.


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## scblur (Jul 15, 2010)

JB weld is not good for this. I think its repairable though. Unless you are aching to spend money.

See someone that repairs composites. 
It would be best done by prepping the surface, adding material, resin and a substrate. Sanding everything down and painting the area glass black. It can be fixed, I wouldn't think twice about it.

- be certain to drill stop the end of the crack. Very important.-------------------------------O See the line, then the O, the O makes a stress reliever.

BTW... I am not recommending anyone do this, but I would do it. Please feel free to give me the frame. What size is it?


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## rtarh2o (Dec 18, 2009)

From the picture it appears that the crack is at the top of the seat tube above the top tube?
That being the case it would be an easy fix for anyone who has used carbon fiber before. The repair is actually easy and there is a lot of information online. I am riding 3 bikes right now that I have bought cracked and repaired myself and haven't had any problems with any of them. 
I also believe that because of the location of the crack it wouldn't be dangerous to ride assuming your seat post goes quite a ways into the frame. I would think the crack would not move any beyond the junction of the top and seat tubes, there should be quite a bit of material there. 
Fix it!
Rusty


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## PDex (Mar 23, 2004)

West Coast: Calfee
East Coast: Harry Havnoonian.


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## Rolando (Jan 13, 2005)

Looking at the photo, it appears that tightening that bolt too much in the past has driven whatever that piece is that is inserted into the tube down into the tube too far and it is starting to split. If you do put some fibers on that as a repair, make sure a good percentage of them are oriented 90 degrees to the crack. I would be willing to bet that there are no 90 degree fibers in the existing tube as it is. The designers depended on the +-45 degree fibers to handle these types of stresses. They just failed locally.


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## jlandry (Jan 12, 2007)

Duct tape it. Then you'll have a little suspension seatpost action goin'.


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## Oracle7775 (Sep 16, 2009)

jlandry said:


> Duct tape it. Then you'll have a little suspension seatpost action goin'.



Winner!


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## fleetseat (May 1, 2008)

*Update*

I ended up sending the frame to Calfee Design and they did an OUTSTANDING job on the repair. I've put this through the paces (hard sprints, etc) and I trust it completely. $300 (including shipping) plus a 5 year warranty on the work beats buying a new frame. Thanks for the advice everyone!


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## Sebastionmerckx (Mar 6, 2008)

Wow, that turned out great!


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## rward325 (Sep 22, 2008)

Definitely came out well. That is as good or better than any of the repairs I have seen come out of Calfee.


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## RRRoubaix (Aug 27, 2008)

Beautiful! Nice to see such clean work- good to know that I can count on Calfee should the need ever arise.


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## waldo425 (Sep 22, 2008)

Looks very well done indeed. Looks l like they even replaced the bolt for you :thumbsup:


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## cxwrench (Nov 9, 2004)

damn...that's a nice way to start the new year! they did a great job...very cool.


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## Dajianshan (Jul 15, 2007)

Wow! Impressive. Thanks for the follow up. Lots of folks come to these forums with a problem and never follow up if anything worked. 

That looks great.


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