Q: How can I paint over carbon fiber wheels (e.g. Specialized tri spoke, disc wheels and Zipp wheels)? How hard is it to do custom paint on carbon fiber? What materials do I need? Any recommended readings or URLs ???
A: Yes, you can paint over carbon fiber. Call JB for a pro job, or do it yourself. In my experience this is how it's done:
1. Remove stickers and their adhesives (I use DX-330 or acetone).
2. Hand sand off some of the old clear coat or paint, if present. Decals under the clear coat can be sanded smooth this way. Stop sanding immediately at any spot if you touch carbon. It is incredibly easy to remove carbon by hand sanding. Watch especially near sharp edges (airfoil trailing edges on wheels, frames and forks) and parting lines on molded parts (often along the center line of frames and wheels, often along the sides of forks). Wet sanding helps keep the dust down.
3. Clean the surface mechanically and chemically as follows:
- Mechanically clean: remove stuff like paint flakes, old bits of dried substances, stickers and their adhesives, decals, flapping plies, scale, crud, etc.
- Chemically clean: remove grease and oil: fingerprints, real grease from old bike parts, oil from the old bike chain, etc.
- One last wash: rinse and scrub with acetone until white paper towels come clean.
4. Prime using Fill'n'Sand or similar. Fill'n'sand is just a high-build primer intended to hide small imperfections, which, depending on your level of perfectionism, is optional ;-). Any similarly described product should do.
5. Paint using regular paint (Imron, Deltron, PPG, spray can, etc.) as usual. Do not exceed 100 degrees F. Some pinholes may appear. I think this may be outgassing. Bake at lower temps or let the paint dry at room temp to avoid.
for West System's recommendations for preparing a newly cured epoxy surface for paint.
1. Do not media blast with any media! Not sand, not plastic, not glass beads, not walnut shells, not steel or ceramic shot. Nothing! Not at even the lightest pressure or for even the shortest time. It is incredibly easy to eat away the carbon and epoxy. Before you know it your part is ruined!
2. Do not use chemical paint strippers! They will attack the epoxy resin that holds your part together. Acetone, alcohol and other solvents are okay, but they don't remove paint.
3. Do not use heat! Some epoxies undergo glass transition as low as 150 degrees F or so. Keep it under 100 to be safe. If it is too hot to touch with your bare skin, it is too hot. That means no power tools (buffing wheels, sanding discs, etc.) and no heat gun paint strippers, etc.