Two Wheel Blogs

If you have a bit on your rig that is carbon fiber, or carbon fiber wrapped that has lost its luster, you can repair it easily. These instructions apply to non-structural carbon such as brake levers or bottle cages. The same instructions can be used on structural carbon also (such as frames, forks, seat posts, you name it), but I do not recommend it as you may be hiding damage that can wind up hurting you when it fails.

We have all probably seen carbon fiber brake levers. They look pretty, and they are pleasant to use (I like that they are not cold to the touch in winter). The problem is, you could probably scuff them up with a hard stare.

Well, fear not because this stuff is no harder to work with than any other painted surface. In fact it is easier, because you do not have to worry about color matching.

These instructions are so simple. Just sand off the old clear coat (and painted graphics if present), remove all sanding dust, and spray with clear coat.

Want the specifics?

I started with a set of lever blades that were scuffed, scratched, and had portions of clear coat flaking off. This is a problem because with the clear coat flaking, some of the carbon fibers are exposed and can easily be damaged.

Here is something you may not know…The sexy little woven pattern you see on a lot of parts…is just for show in most cases, it is typically referred to as the “cosmetic layer”. If you are lucky this layer is not damaged from the scuffing. Another set of these levers I have had damage to this layer so the levers have patches of black where the cosmetic layer was partially lost.

Because carbon fiber is a fabric sheets bonded together, once this cosmetic layer is exposed, the elements have an easier time of permeating and propagating through the weave by migrating along the fibers and causing more flaking of clear coat.

Step 1. remove the hardware from the carbon fiber bit and clean the piece. It is pretty important that you remove all the grease and grit that can ruin your work. I used some isopropyl alcohol on a cotton cloth to remove grease, oil, etc. I used a new cloth with isopropyl alcohol for each step throughout this refinish.

Step 2. remove the material you want to replace. I started out with 180 grit sanding medium (Emory cloth). This stuff is quite coarse for finish work so take it easy on your elbow grease application. It works fast and will generate a lot of foul smelling dust; it smells a bit like epoxy when you get into the carbon (see why I do not recommend this for structural components?). You are done when you achieve a smooth feel that appears uniform (no light spots indicating trapped air under remaining clear coat). When you think the surface is smooth use your tack cloth to wipe the dust away. The moisture will show you what it will look like once the clear coat is applied (the wet look). This will be dramatic because when it is sanded it will look like hell until it gets wet. The alcohol will evaporate quickly and it will look bad again, do not worry.

Step 3. Now that it is dry and clean, can you see little scratches and sanding marks? Probably. Most will not be visible once clear is applied, but you can get some ultra fine Scotch Bright pad (a.k.a. scuff pad) and do a final sanding to remove some of the scratches. I did not bother since I was not going for show quality…though they did turn out pretty good.

Step 4. Apply clear coat. Shoot it in very thin layers to prevent runs. Let each layer dry for about an hour before you re-shoot. I rushed the job and got a couple runs in my work so I had to sand them down in those areas and shot a final coat. This next step is how I did that.

Step 5. You can use this optional final step to go from a pretty good finish to a very good finish if you like. Scuff and polish the clear coat to remove irregularities. For this step you need to use a sanding medium that is ultra fine. You are not going to remove much material here at all. I choose to shoot a final coat of clear on top of this scuff layer, and it turned out really well. If you want to really make it brilliant, use rubbing compound and actually polish the clear coat as your final step (you can use rubbing compound, tooth paste, or automobile polish/wax). Toothpaste works quite well and is pretty easy to find.

Want to get really custom? Find yourself a good paint store that has candy coats. You can apply these to produce colored carbon. I have seen just about every color you can imagine on carbon…when the sun hits it just right, it can be pretty cool.

Lots of guys will use these simple finishing techniques to remove logos, and customize the looks of their bikes…you can too if you are careful and take your time. Refinishing these lever blades was a small job. It took 24 hours, start to finish. The actual labor time was probably about 30 minutes (most of the time was just waiting for coats to dry.

Photos:
1. Before
2. After (and all the stuff you will need)
3. After (close up)...not too bad for a hack?