Painting Carbon Fiber Parts

Question

I have access to a compressor and paintwork tools, nozzles, etc... but I have no experience doing this, what I have is time and willingness to learn.

I have these UD carbon fiber parts that I have removed the original paint, they are small in size, I want to:

1. Paint over the defect zones, these parts are insanely complex, sanding them was a total nightmare, and some parts are bonded together, I want to hide those seams, likely with dark purple paint.
2. Leave the rest exposed and clearcoat it, (after all UD carbon looks black), so that it looks glossy the same way it looks when covered by water.

I don't want to spend more than the part costs, after all I don't need 5L of paint, 100ml of paint can hide all the seams, and 300ml of clearcoat are quite enough; I am hoping to spend 50EUR or so in the paint and clearcoat, I want high quality, but small amounts.

What can I do to achieve this? any time I google on the internet I get completely opposite advice, from you need a 2k urethane coat, to a catalized polyurethane coat, from oil based is good to water based or the parts will melt, to it needs to be epoxy based.

I know how to do the masking, hell I prep the surface so that water doesn't want to stick to it given how smooth, 2000 grit, but I am lost with the paint part.

Answer 1

Not sure exactly what you are trying to achieve, but I'll lend my [very limited] bodyshop knowledge to your challenge.

Sanding anything to 2000 grit before basecoat is pure folly. Sanding carbon fiber is even worse: It's like trying to sand sandpaper. By nature it has texture, and most of us want the "look at this - it's carbon fiber" texture to be prominent.

I'd base layer anything that you truly want to paint with epoxy prime, and then rough that (maybe 400-600 grit) for a color coat. THEN you can color sand with 2000 grit, and apply clearcoat of your choice.

For just general clear over carbon fiber, just to make it shiny, I would clean prep well but with limited to no sanding. Polyurethane clear and be done. To get a flat mirror finish on CF will be a huge number of coats and work, but I suppose it could be done. I've always thought that carbon fiber looks great as it is, better with some clear, but I've never thought I need a perfectly flat substrate to start. It's carbon fiber after all, and I think it should look like a textured landscape representing what it is.

YMMV; best of luck.