Textured carbon fiber parts?

General Composites Discussions Composites Talk
#1

Has anyone here got experience of making carbon fiber parts with a textured surface instead of glossy smooth?

I am having trouble replicating a part where the original has a textured surface like this:

The original can not be sanded smooth and the shape have too many small narrow corners and grooves to be sanded smooth at the mold stage. I tried casting a new plug and sanding that smooth but I’m finding it impossible to maintain the original proportions.

So I’m wondering if anyone has successfully made a cosmetic cf part with a rough textured surface like this? Can it be done without leaving the surface of the part covered in air bubbles?

If you had to make a cosmetic cf piece from an original with that kind of texture, how would you do it?

#2

In theory you could make your mold and then just do an in mold clear coating. That should semi level and then infuse. When you pop the part out you can knock it down and then reclear of need be.

#3

I agree completely :D.

You can also make a mould, make a product, make it smooth, make a new mold.

#4

Precisely, that’s what I do with parts like this. Most auto interior parts that I’ve done tend to have a textured finish, I’ve always done these big just knocking the final part smooth. If you can’t use an in mould coating, just sand the part smooth and then clear.

#5

If you were to attempt using a layer of clear resin in the mold to level it before the layup, how would you prevent a build up of mold release in textured surface?

Also, how do you apply the clear resin to vertical surfaces in a way that prevents it dripping down and pooling in corners? To level the surface would require more resin that you could apply with a spray application and even my thickest clear resin won’t cling to vertical surfaces (and there are lots for this part).

I have been having a hard time sanding the texture off because it’s so deep (or rough). I first tried casting it in a urethane resin but none of mine sanded well. I got close with epoxy putty but the dimensions were off when I was done removing the texture.

if you were to choose a material to cast a new plug from that was easy to sand smooth, what would you guys use?

I don’t normally struggle with problems like this but this one part is my nemesis…

#6

This is the part I am making btw:

I have made it tons of times as a painted carbon fiber piece with the texture in tact but not as a cosmetic piece.

#7

I make similar parts to yours above, and working with an existing plug is a bit of a pain. The textured parts surface in your pic looks to be an epoxy paint, pretty typical in the stock manufacturing world. t’s similar to texturing drywall and it hides a multitude of sins and imperfections, plus gives some grip to the part. The parts that I have seen with texture like that generally do not have shells, but are pour cast and then sprayed with the epoxy texture. You can see the benefit to not needing to lay up a shell, vs just pouring/casting the part, but you do not get any benefits of the rigidity a CF or fiberglass shell offers.

My approach would be to make a temp mold of the original part, pour a plug using epoxy and filler (3m micro) and work with that to make a master plug. Access to a 3D scanner and CNC would make quick time of the duplication, but you may not have that luxury.