Fixing a chipped/broken carbon downtube cable stop

[hockeybike]

Hey all,

So I recently purchased a gorgeous cyfac gothica on the forum and as I was building it up noticed that the Downtube cable stop was cracked. Not sure how/when it happened and that's a separate issue, anyway.

My immediate question: What's the best way to fix it? Here's a picture:

http://imagizer.imageshack.us/v2/xq90/854/h2or.jpg (https://imageshack.com/i/nqh2orj)

Thanks in advance!

[buldogge]

Get together some 2-part epoxy, some sandpaper, some matching touch-up paint, and some clearcoat.

Use a sacrificial cable end with some oil or foil on it, so the epoxy will surround it but not stick.

Fill the area and then sand the epoxy to shape (tape off surrounding areas), including internally if necessary.

Paint the touch up, cure, and then sand with 1000 and 2000 wet.

Clear...sand with 2000 wet...then polish.

-Mark in St. Louis

[Tony]

Get together some 2-part epoxy, some sandpaper, some matching touch-up paint, and some clearcoat.

Use a sacrificial cable end with some oil or foil on it, so the epoxy will surround it but not stick.

Fill the area and then sand the epoxy to shape (tape off surrounding areas), including internally if necessary.

Paint the touch up, cure, and then sand with 1000 and 2000 wet.

Clear...sand with 2000 wet...then polish.

-Mark in St. Louis

One thing I would add is to thicken the epoxy with fine wood flower or colloidal silica, even toner from a copy machine. This is like adding aggregate to cement, it strengthens the epoxy.

[hockeybike]

Interesting ideas. Any recommendations on the type of epoxy to buy?

Also, any one know of anyone in the DC area who might be decent at this sort of a thing?

[R2D2]

Plastic wrap works great to wrap the ferrule.

West System epoxy is good.
Add a filler or you can use some fine chopped up fiber glass / carbon fiber to provide some structural integrity.
Marine store should have all you need. Take a picture and show someone at store. There's usually some experienced guys around that could give some good pointers.

Also JB Weld is readily available at Walmart/HD/Lowes/Auto and may work fine.

[hockeybike]

R2D2 -- or anyone else, is there a particular west systems or other epoxy i should get? I see plenty of options and figure this is one of those do it once and don't do it again type of things.

[Tony]

R2D2 -- or anyone else, is there a particular west systems or other epoxy i should get? I see plenty of options and figure this is one of those do it once and don't do it again type of things.

G flex, http://www.westsystem.com/ss/g-flex-epoxy

Loctite E 20HP, (my favorite) http://www.henkelna.com/industrial/product-search-1554.htm?nodeid=8797912727553

Mas epoxy, http://masepoxies.com/

West systems, http://www.westsystem.com/ss/

[bobswire]

R2D2 -- or anyone else, is there a particular west systems or other epoxy i should get? I see plenty of options and figure this is one of those do it once and don't do it again type of things.

Super glue and some kind of filler. Just have to build if up kinda like this > http://www.youtube.com/watch?v=slCMkvEfK_U

[Tony]

I would stick to structural adhesives. The Loctite for instance has a shear Strength of 3270 psi and a tensile strength of 5700 psi

[sworcester]

Super glue and some kind of filler. Just have to build if up kinda like this > http://www.youtube.com/watch?v=slCMkvEfK_U

Don't use Super Glue or a CA glue, too brittle for the long term. If you can boltster up a mold, even with some tape and then sand down a 24 hour epoxy, you would be better off long term. 5 minute would work. but would possibly more britle. May not be as pretty, but would hold better. If you can mix in some thickener like something that the manufacturer recommends (big fan of West) then it may help out.
My experience comes from the wood art world here archival is the money.

[hockeybike]

Thanks for the suggestions, all.

The more I think about it, the less I think I'll have time to take care of this before the weather is decent.

WIth that in mind, anyone know of any decent carbon repair shops on the east coast? If none pop up, Ruckus it is.

Thanks!

[hockeybike]

Ok, so I had some time on Sunday and used what I had lying around -- some JB Quick. Taped off the non-broken areas and applied a decent amount. Came back a day later and the sacrificial ferrule came right out -- great tips on wax and oil.

Unfortunately, the second I inserted a new ferrule into the cable stop, the epoxy coating cracked off. Didn't take any carbon or paint off with it, either, which makes me think it didn't bond too well with the paint.

Would it be worth it to try again and sand the cable stop a bit to rough up the paint and get a better bond between the epoxy and the frame?

Also, is there a big strength difference between JB weld quick and regular JB weld or any of the other listed epoxies here? The quick stuff seems like it broke...quickly.

[boywander]

I don't find it necessary to sand the application area unless the epoxy manufacture calls for it. I personally like 3M green.
btw, I'm in the Wdc area.

[hockeybike]

Thanks -- I actualy gave up on the DIY way and just sent it to ruckus. Other side cracked too, and neither the epoxy putty nor the jb weld held up well.

[kramnnim]

How much is the repair going to cost?