Corroded cable stop

[Bentley]

So a couple of questions

I purchased a used carbon/TI bike frame, really clean but there is one area of concern, basically an aluminum cable stop that is rivited to the carbon tube is starting to corrode. My sense it’s plain ol galvanic corrosion since the aluminum river
T electricaly connects the carbon to the aluminum.

I’m thinking of drilling out the rivet and using JB Weld to re-bond. Thoughts?

[Dude]

Is it a brake or der cable stop? If it's brake cable stop remember that your life literally depends on that cable stop remaining in place.

If that's the case, have a professional affix it to the frame. This is all under the assumption that the cable stop is structurally compromised, not just aesthetically.

[ultraman6970]

If you are comfortable doing half of the repair why dont you do it completely as it should???

Remove the rivets and the cable stop... sand the carbon area and clear it really well with like 4 coats of clear coat (or same color of paint than the top tube) so you have no contact what so ever again between the 2 surfaces... sand to make it look nice... repaint the cable stop the best u can... I imagine is black in color?... and then reinstall with new rivets?

Some peopel swears for the jbweld thing, I never been able to get that putty right and honestly probably wont look right either.

The other solution is just sand the area affected as much as you can and just clear on top.

[Bentley]

I am not referring to the "putty" version i am talking about the two-part epoxy.

my thinking is a new rivet will still give the galvanic corrosion situation so its never really going to be a permanent fix. Also, the wall thickness of the carbon tube is an unknown so that is also a.little worrisome.

Ray

[Peter P.]

Remove the rivets and the cable stop...

Even if you follow your method, the rivet is contacting the carbon on the inside of the tube. You won't improve the situation.

Perhaps a carbon repair facility has a better method such as stainless steel rivets.

If Bentley really loves the frame, then it's worth having a repair facility perform the repair, and maybe redo all the other cable stops while they're at it.

[Bentley]

Even if you follow your method, the rivet is contacting the carbon on the inside of the tube. You won't improve the situation.

Perhaps a carbon repair facility has a better method such as stainless steel rivets.

If Bentley really loves the frame, then it's worth having a repair facility perform the repair, and maybe redo all the other cable stops while they're at it.

So I’m not sure any rivet that is metallic is going to really do any better. I can isolate the cable stop from the Carbon, but any rivet completes the electrical circuit, that is the problem.

That said, does anyone know of a competent repair shop for doing the repair?

East Coast is better, but I’ll send it to the best person regardless.

Ray

[ultraman6970]

Well this is the thing... some bikes dont develop the problem and they still use rivets, that the issue with some colnagos, specially the 1st generation c40s and c50s, till they figure it out what to do. I have a c50 and never had the problem.

Nobody says you cant paint the interior of the carbon tube, just use a tiny brush and try to get paint in there. Same with the rivet, paint the rivet just as cautionary measure?. No idea if there's titanium rivets either.

Nova cycles has anodized cable stops btw...

https://www.cycle-frames.com/bicycle-frame-tubing/NOVA-CABLE-STOP-SINGLE-RIVET-BLK.html


And you can google anodized or painted rivets.. those things are available, so i dont see why not to just dip a regular rivet into paint and use that, after all the center part doesnt touch the carbon so the corrosion wont start there again.

[prototoast]

Use epoxy plus pop rivets. The epoxy can help act as a barrier to inhibit corrosion Clean it really well, and unless you live near the ocean, you'll probably have at least 10 more years before you have to do it again.

[Peter P.]

That said, does anyone know of a competent repair shop for doing the repair?

East Coast is better, but I’ll send it to the best person regardless.

Ray

Hot Tubes in MA (http://hottubes.com/carbon-fiber-repair) is a carbon repair facility.

Report back if you get it repaired; let us know how things turned out.

[Satellite]

I sent my C50 to Calfee to get the brake stops repaired from corrosion.

[jpritchet74]

So I’m not sure any rivet that is metallic is going to really do any better. I can isolate the cable stop from the Carbon, but any rivet completes the electrical circuit, that is the problem.

That said, does anyone know of a competent repair shop for doing the repair?

East Coast is better, but I’ll send it to the best person regardless.

Ray

I had a pair of cable stops replaced by Ruckus Composites earlier this year on a Colnago Extreme-C. It looked perfect when I got it back and the cost to replace a pair of cable stops was only $150 + shipping. That was much cheaper than the quote that I got from Calfee.

https://www.ruckuscomp.com/

[duff_duffy]

I’ve recently found the jb two part epoxy does not work well with shear forces and think that is what that cable stop would be under when cable is under load.. Under compression/tension stuff was great though!



I am not referring to the "putty" version i am talking about the two-part epoxy.

my thinking is a new rivet will still give the galvanic corrosion situation so its never really going to be a permanent fix. Also, the wall thickness of the carbon tube is an unknown so that is also a.little worrisome.

Ray