Plainsman

Slight scuff spot on a bike, gloss clear over nude carbon. Quite small spot appears white, but has almost no depth at all, practically none - assume it’s in the clearcoat - so fresh clear should fix it. Two questions:

best touch up -Automotive clear coat or plain old nail polish?

best way to prep the small spot - alcohol? acetone? light thinner? soap and water? scratch/swirl remover? other?

Andrew R Stewart 

First thing to understand is that it take real skill and care to refinish a spot AND have it blend in with the OEM finish. Just about all bike finish touch ups I've done/seen are pretty glairingly obvious. Very few people will do the after touch up work to best blend in the patch with the OEM finish. Think very fine wet sand paper (400/600+ grit followed by rubbing compound).

I usually suggest being at ease with the current cosmetics if at all possible. Carbon fiber constructs are pretty resistant to water and oils even without any cosmetic coatings. If you must try a patch of the finish assume it will show easily and be bigger in surface area then the bad spot is.

It will help if you are able to learn what the OEM clear coat is so that any patch is not a different tint or subject to UV or other discoloring at a different rate. Or just use nail polish and ride the bike. Andy

sch

IME with clear coat on a bike with powder coat color coat and PC clear coat on top, I was putting decals on
and used automotive rattle can clear coat to cover the decals, the automotive CC was quite thin and
I ended up using 6-8 coats (they dry fast) with the knobbly areas at the edge nicely smoothed out with
automotive polishing compound. In the end it was all smooth and equally shiny. And of course the
automotive CC has UV resisters built in.

Prep with dish detergent in water followed by alcohol wipe off.

Plainsman

. Thank you Andy, points well made, and I do recognize that a true professional level finish is not a likely result for the do it yourself-er. I have a few bikes that need attention. Some I’m just looking to hide battle scars, some a little more refinement, none am I expecting a factory finish. Let me ask this - if I simply try the clear nail polish and don’t like the result, is there a safe way to clean it off and get back to the starting point? At least that way I can decide whether the fix looks better or worse than the mark, and choose the better of the two. Thanks!

Crankycrank

If it's a shallow scratch and your only trying to smooth it out and get a glossy finish then just get some automotive paint scratch remover paste. Works on epoxy resin coatings as well. Sold in most big box and auto stores. No clear coating needed.

Troul 

If it's down to the fibers, you'll want to apply a resin to reseal the distressed area, that's after you clean the area & feather the area with sanding paper that will promote adhesion (120 grit). After you build back up the areas strength with resin, you can dress the area with a UV resistant clear coat. Look into the West System 105, 206-A Epoxy Resin.

Plainsman

I’m testing on one that’s def not down to any fibers. Wondering if simple clear nail polish will smooth it out and remove the haze. If it looks bad, can I clean it all off with non-acetone nail polish remover, or is that bad for the factory paint and clear? It doesn’t photograph well, otherwise I would post a pic.

Troul 

Once you apply the coating, you'll need to sand away said coating after it has fully cured.
If the indentation is noticeable now, before you do anything, I suggest using the resin to "fill" the void leaving just enough to build up a blending finish to the remaining surface (using a paint or clear coat that is UV resistant) .