rovis

Hi,
The chainstay cable stop broke on my Bianchi intenso. I had no luck contacting their US distributor, their Italian support, or finding a replacement part anywhere. Contacted some carbon frame fixing shops, and it doesn't look like they are interested in a job like this.
The ideal plan is to find the part and glue it and rivet it to the frame.
However, since it looks like there's no chance with finding the part, any alternative ideas? I'd like to keep the fix as close to original shape as possible.

Iride01 

I'd just clean and sand the area on the stay where it goes and put some resin on it and let it cure. You might find someone familiar with CF and see if just regular Epoxy resin is okay or not.

Epoxy will be stronger than that rivet. So don't even bother with that. A hole in that part of the stay might not be a good thing. A little bit of glass or carbon fabric layered over the foot of that stop and onto the stay will further make it stronger. But that might be more than is needed.

sportifcx

bring it to a shop they might replace it through a warranty type thing or give a crash replacement option

dsaul

This is probably the closest thing you will find without getting an original part. https://cycle-frames.com/collections...t-black-finish

Pratt

Epoxy should be as strong as the original (should have been),
Ditto on avoiding drilling a hole.
If the picture in the OP is the before, I might be tempted to try to reduce the height, and thus the lever arm on the base adhesive.
If I were in your situation, I would also post this in Bike Mechanics for a higher liklihood of an authoritative answer.
Good luck.

rovis

Yes, from my research, Araldite is a common epoxy used in carbon frames. There are two small holes actually, but that shouldn't be a problem to cover in case I use only glue.
You think only glueing the part would be strong enough?

None of the LBS's are interested to work on this kind of repair. Bike is from '14-'15 and I'm second owner. No warranty anyway.

Yes, this was recommended to me this morning by a shop in Colorado. Waiting for their reply and yes, the part you link to, looks like something close enough to original.

Iride01 

The nice thing about Epoxy and most resins is that they can be sanded down if the thing comes off again. And you can try again every time it comes off. Never messed with carbon fiber but I have done a lot of fiberglass work on a sailboat I use to own for over 10 years. Epoxy is strong stuff. Glass reinforced epoxy even stronger.

You keep using the word glue. I guess you are thinking epoxy glue. It's pretty much the same thing as epoxy resin but some are cheaper formulations and less strength. Also, they tend to set very quick so you have to be over and done with everything you are going to do real quick.

The holes in the stop that was linked by @dsaul will be nice to let the epoxy come up through and further add some mechanical holding power to the bonding power of the resin. Still don't think any sort of rivet or pin necessary. But if you do think it is then do it.

Barry2 

If you go the epoxy route….
use a slow setting epoxy and pay attention to the temp limits.

Barry

MarcusT

If all else fails, use cable housing the full length of the chain stay

dedhed

They make clamp on cable stops.

or this for the original.

​​​​​​https://www.amazon.com/64-HOSE-CLAMP.../dp/B003YVPBPG

rovis

Yes, this was suggested by one of the LBS too. Probably still needs to be anchored somewhere along the chainstay.

rovis

I was thinking of something like this initially. Not a very eye pleasing solution, but workable. With some rubber between clamp and frame and some epoxy, it should work.
But, I'm still trying to find something as close as possible to the original.

Pratt

A sort of hybrid solution might be to use a clamp on, but just clamped lightly, just enough to hold it in place until the epoxy resin under it sets, not hard enough to crush, or even distort the carbon fiber beneath it.
Now that I think of it, there is, on CGOAB, an extensive thread with color glossy photographs, of a guy building a carbon fiber recumbent frame. It should give you both ideas, and confidence that a DIY repair will work.

MarcusT

https://www.amazon.com/Yuauy-Deraill...%2C153&sr=8-52
or
https://www.amazon.com/Yuauy-Deraill...%2C153&sr=8-52

Again, only if all else fails. It's not the best looking solution

blacknbluebikes 

I just had this problem fixed on a carbon frame. My attempt to fix with epoxy failed - popped right off under load. I found a great guy here on the east coast that did it properly - Carbon State Repairs, LLC . Highest recommendations I can give on him, Tom, and his work - does all kinds of frame repair, but only frame repair. Now, if you're on west coast you probably don't want shipping costs. I did a web-estimate with Calfee, but it was beyond my budget. Mine needed to be "re-riveted", filled, prepped, then done with some totally bad-ass industrial epoxy, not mortal human stuff. First time I ever saw a double barreled caulking gun.

rovis

Thanks for your feedback. I've contacted Calfee also, but the type of repair doesn't quite justify the implied costs. I've ordered a stop from cycle-frames.com to see if it fits. And will go the epoxy way for now. Since the stop and the frame have holes for rivets, I might add the riveting.

On your first attempt to epoxy only, did you prep the area before? Like sanding the frame/stop, etc. Would it be possible to find out from your local guy what type/brand of epoxy he used?

Here's a photo of the affected area in my case:

Iride01 

So there are holes there already. What is the shiny metal looking stuff in the hole on the left? A threaded insert or remnants of a rivet?

Did any of the CF repair places you talked to go into any detail about what they do?

However still with glass work on my sailboat, I found that even it you do a piss-poor job the first time, you can always come back and rip it out and do a slightly less piss-poor if not perfect job the next time.

There have been DIY'ers here in the past that messed around with actual CF repair kits and seemed to do a very good job.

Pratt

With existing holes like those, I would consider a couple of screws threaded, lightly into the holes to reinforce a composite stop. There looks to be plenty of surface area to roughen, clean, and glue to. Epoxy in those holes would also seal any exposed matrix against water intrusion.
Good luck.

rovis

Not really, LBS's had same ideas as were exposed here, the CF repair shops either wanted to take a closer look (none close enough to warrant a trip), or simply quoted their standard starting prices (around $300 for most places).
The holes in the frame let me think this part was most likely riveted, not even glued to the frame. If you look close enough at the photo, you can't see any residue from any glue where the contact between part and frame was. You can see a round outline of the original and gunk accumulation. In between holes, there's a cleaner area, which either was the contact patch between frame and part, or simply not, depending how the profile of the original was.
It also looks like one rivet came off cleanly, the other got partially severed.

Waiting on the replacement part from cycle-frames and will attempt the epoxy and maybe riveting.

blacknbluebikes 

rivets are a must, and they're rather small - can be tough to get the head of a rivet gun inside the stop. I dunno about the epoxy, it was 3M and black.

stefthehat

Depending on size of replacement stop and how many attachment holes are on it,I’d recommend ‘dry mounting’ over one of the existing holes ,then put masking tape on all four sides of stop ,you now have the ‘footprint’ ,using approx 240 grit paper ,remove all the paint back to the composite ,do the same on underside of new stop ,if it’s anodised alloy try and key up until anodising is off,maybe also key up the first few mm’s up the sides of the stop,find a v small ‘self tapping’ screw whose head nestles in stops countersunk hole ,now remove all tape ,blow off dust ,wipe all bonding surfaces with acetone or similar not meths or kerosen etc ,make sure everything is dry,hairdryer or hot air gun ,now remask borders of footprint allowing an extra 1 or 2 mm likewise if possible run masking tape around the new stop again allowing an extra mm or so if possible ,trim with a sharp blade so you have access to counter sunk hole ,now using an ‘epoxy structural adhesive’ such as the 3m range or Plexus [sorry you will have ALOT unused ]put the epoxy on both surfaces and into the old rivet hole ,squeeze them together also pushing the screw through the hole into the embedded epoxy clean up top of stop and screw head with acetone on ear bud or tightly rolled cloth,run wooden mixing stick or some such around the stop to clean up expressed epoxy ideally leaving a slight amount at interface ,tape over stop to chainstay so there’s a medicine of pressure ,been in composites repair/manufacture game for 35+ yrs and just done to process to a carbon frame at both chainstay and dual cable mounting on front end of downtube

stefthehat

Avoid hardware store small blister packs of craft epoxies aimed at gluing mug handles back on ,methcyclate based epoxies are very good ,over on your side of the Atlantic everyone is obsessed with JB weld products the double syringe pump products at the top end of their range that specifically list strengths after curing and are epoxies are a not awful replacement for the industrial 3m epoxies

Pratt

I like Stef's masking suggestion. What I have done is cover the whole area, after sanding and prep, place the hardware item and run a sharp blade around it. Then remove the tape that was under the hardware. The resultant space is perfect.
Alternatively, you can cut away the excess epoxy when it is "green" partially cured and still flexible.

rovis

Thanks for the detailed instructions! I was looking at the 3M's products and is simply overwhelming! I kind of narrowed it down to Scotch-Weld products.
https://www.3m.com/3M/en_US/p/c/adhe...tt=scotch%20DP
The replacement part is aluminum: https://cycle-frames.com/collections...t-black-finish

mr_bill

Right after my achilles tendon healed, my rear derailleur stop failed. (Similar injury, lol.)

I ran full cable from the front cable stop to the derailleur under the bottom bracket, and all was well.

Found a cable stop that matched.

LBS was WONDERFUL, bought the bike from them, and they sent out the frame for repair with the matched cable stop to a specialist.

The repair lasted a couple of months before it too failed. (The stress of a cable stop is much higher than many people imagine.)


In hindsight, I wished I'd just stopped at running cable under the bottom bracket.


So, don't let pretty be the enemy of a good honest repair is my advice.

-mr. bill