Repair Carbon Fibre / Carbon Wrapping?

I have a set of carbon TT handlebars that have cracks from someone over-tightening a bar end brake. I could get these back to the guy I bought them from and may have to, but looking to see if any of you guys have done a carbon repair, and how successful it was.

Since this is right on the end of a tube where there is a lot of pressure (downward from hands, and outward from expansion bolt of brake, and also from brake lever compression) I guess that a full wrap around the tube would need to be comprehensive?

Any ideas? Is the fishing pole repair kit really enough?

Cost of facial reconstruction vs a new set of bars?

If you just bought it then bring it back, don't bother. But yes doable and fairly easy, you need to remove the varnish then apply few layers of carbon with epoxy to reinforce the section and finally apply a new varnish. Carbon isn't very hard to deal with, now is it worth it? probably not especially if you can bring it back.

Well it was bought from someone on here, in good faith, and they were unaware of the cracks. It would be very difficult to source the same bars at any price. The seller is happy to refund but is also wondering the viability of a repair (regardless of if I keep them or not.

I see what you mean, you can negotiate a new price and invest into a carbon repair kit (between £25 and £35). You will need to buy some clear varnish too. Laying carbon is fairly simple if you understand the constraints on your handlebars. It is the end where the brake is fitted so you know the force will be from the inside to the outside. Then one layer all the way around overlapping itself should do the trick. On top of that, you have a bending/flexure constraint coming from your weight holding the handlebars. So i would lay down with an angle some long (but not large) strip from the body of the handlebar all the way to the end (brake side). You probably should cross those layers to improve rigidity. That would create a new very robust structure. Probably overkill but at least you would be 100% safe, we are not talking of optimizing the critical point of the handlebars but reducing weight here.
You can then saw/paper sand the excess at the end to fit your brake (remember to wear a mask, very toxic stuff) to get something clean. One or 2 layers of varnish and you are done but keep in mind you probably will end up with a slightly wider outside bar than the other side (carbon layer are very thin, probably not by much).
I designed and repaired many carbon components, very easy to do once you get use to the way it behave when soaked with epoxy.
But i still would give it back and hunt for another one, not worse the hassle except if you want to have the pleasure to do it yourself.

There's carbon and then there's carbon. To be honest I wouldn't recommend those cheap kits, I have thoroughly tested them in the past (testing procedures for wind turbine blade repair... don't ask) and haven't had the best results (lots of delamination i.e. layers peeling apart) as far as I can tell this is due to the epoxy.

I would recommend West System 105 Epoxy with 406 Colloidal Silica filler (best for what you want to do), 200g carbon cloth (I use Cytech; other brands might be fine, don't really know, it's all we can get here). Remember that epoxy doesn't really bond to epoxy very well, so you'll need to do a lot of prep (sanding, cleaning) beforehand - google it.

I'm not trying to put you off - carbon's pretty easy to work with, much easier than most people think, but any repair is only going to be as good as your weakest link, be it materials or technique. Perhaps practice before you go in head first.