Talk Composites - The Forum for Advanced Composites

Do I need to wait until it cures for scratch to dissapear

http://www.talkcomposites.com/Topic36673.aspx

By TheMidnightNarwhal - 5/14/2020 11:02:47 PM

I sanded my carbon fiber lip down with some a 80 grit and I'm on my second coat of epoxy after applying it a to a previous tacky coat and I still see the scratches and the road "rash" mini chips.

Is it going to turn invisible and sit into it properly once it cures fully or did I F something up in the prep phase or it's just the carbon weave that is scratched? I'm about to do a third tacky coat now and let it cure and level it with some 180 grit then probably do 2 other coats.

https://i.imgur.com/hJSo0OT.jpg
By Hanaldo - 5/15/2020 11:48:50 PM

Yeh you've gone through the carbon there. Can happen so easily with parts like that, a single layer of carbon is only ~0.2mm thick.

The previous chips and cracks appear white for a different reason though, it's simply refraction of light. When the clear resin cracks or chips, it creates a rough surface that can reflect light rather than the light passing through it like it did before the damage. Kind of like how a car windscreen can be perfectly clear, but when it cracks or chips the damage will appear white or green. On the black carbon background, damaged resin appears very white by contrast.