Originally Posted by
Captain Slow
A scratch can be superficial. CF frames are a lot stronger than you'd suspect. I've seen many frames & forks with cracked paint... especially forks... from the normal flexing that comes from use. Looks scary, has no structural implication.
That said, what you call a "deep scratch" might be described by someone else as a "gouge, trough, dent, or puncture" of the carbon tube.
Best thing to do, then, is to ease your worries. Have a bike shop look at the frame and pronounce it safe or unsafe.
The shop that looked at the gouge stated that it only cut through the "cosmetic" carbon fiber layer. They explained that there's 2 layers of carbon fiber, the structural one and the "cosmetic wrap" to make it look pretty. Is that true for a Madone?