DIY Carbon Repair

[cmbicycles]

Anyone here use one of the diy carbon kits to repair a frame? Thoughts on the process if you've done it?

I bought a Felt FC as a project bike, and later discovered it has a small puncture near the rear derailleur cable stop. I was going to send it out to be fixed, but was curious about the diy repair kit from Predator or others.

[November Dave]

A small puncture near a cable stop seems like a perfect candidate for this kind of project. There is nothing functionally more difficult in doing a carbon repair than making paper mâché stuff in 4th grade art class. It's just a bit higher stakes.

I wouldn't do or recommend anyone do a repair with an alignment element at home. For that you're going to want lasers and alignment fixtures and just leave that to the pros.

But for a small puncture or crush in a non-critical area, if you follow the process VERY closely then you should get a nice result.

[glepore]

I've done it on a number of frames/parts. Its not difficult to do the actual repair, just consumes a little time. I've used tight wraps of tape where compression is needed.
Refinishing to match is another story...

[rockdude]

Pretty easy stuff, Done it on Seatstays, toptubs and other areas. Heck, I even make parts for my TT bike like extensions.

[cmbicycles]

Where does anyone go to for carbon repair kit/supplies? I know of the predator kit, but any others I should consider?

[glepore]

I usually just buy from one of the ebay suppliers that sell fabric and repacked West epoxy.

[HenryA]

Might try these guys:

https://www.cstsales.com/

I’ve bought from them several times.

[dddd]

Contusions of the stays near the dropouts can be repaired by filling the tube with high-strength resin and without compromising paint any worse than the original impact caused.

[cmbicycles]

Originally Posted by dddd

Contusions of the stays near the dropouts can be repaired by filling the tube with high-strength resin and without compromising paint any worse than the original impact caused.

Curious if you are talking about just filling the puncture with resin, or filling the whole end of the tube?

[glepore]

I'd wrap that. It appears to be broken where the inserted dropout caused a stress point.

[dddd]

Originally Posted by cmbicycles

Curious if you are talking about just filling the puncture with resin, or filling the whole end of the tube?

I meant filling the tube, from the dropout up to about 1cm up past the ding.

I've drilled a small hole and injected mixed resin, then covered the hole with tape and warmed it with a hair drier to thin the resin initially so as to allow any bubbles to rise to the top of the resin. The heat also accelerates the curing process. A vent hole is needed at the upper end of the stay if there is no escape for air there, unless you can compress the air slightly with the syringe flow and hold it long enough for a quick-curing resin to harden.
The resin fill is going to make it stronger than when it was new.
My repair was a Giant where a really severe contusion in the upper/rear surface of the tube was caused by the derailer getting pulled fully up and around, carnage!

[muz]

Originally Posted by dddd

The resin fill is going to make it stronger than when it was new.

I don't think strength is the primary factor for this repair. The problem with this approach is that it creates a stress riser at the boundary (where it transitions from solid fill to original chainstay). The repaired area will be very strong, but it will crack at the boundary sooner or later.

[glepore]

Originally Posted by muz

I don't think strength is the primary factor for this repair. The problem with this approach is that it creates a stress riser at the boundary (where it transitions from solid fill to original chainstay). The repaired area will be very strong, but it will crack at the boundary sooner or later.

This.

[CaptStash]

That is such a teeny tiny flaw I would fill it with epoxy and go about your merry way. I would be stunned if it got worse.

CaptStash....

[glepore]

it is a tiny flaw, but its right where the solid dropout is bonded to the hollow tube. Granted, the seatstay takes most of the vert load, but why take a chance, when it's easy to increase the diameter of the tube.