Carbon fiber finish

General Composites Discussions Composites Talk
#1

I’m new to composites. I’ve made a few carbon fiber plates by laying up fabric and epoxy resin between two pieces of MDF wood and wax paper, basically making a sandwich and then clamping the heck out of it to substitute for a vacuum.

The plates come out pretty good but don’t have the “glossy” cosmetic appearance that I’ve seen on other CF parts. I care more about utility than cosmetics, but it couldn’t hurt to have it look good. What are my options? I’ve heard you can use clear coat in a can as a final finish, but that it may peel off over time. I’ve also heard you can layup with polyester resin instead of epoxy, but it won’t be as strong.

Cosmetics aside, does my epoxy finish need UV protection? The parts will see MAXIMUM one hour of sunlight per week, probably.

Thanks!

#2

wax does not have a “glossy” texture… use seran (sp) wrap as well… that has a very glossy texture. or… try 2 pieces of glass… thick so it doesnt shatter… my .2$'s

#3

yes, your epoxy parts need a clear coat, this will prevent degredation due to UV and prevent yellowing. The clear coat will also add gloss.

#4

parts normally will reflect, quite literally, their mold surface. If your mold has a mirror finish, chances are the parts being pulled from them will have the same. The same can be said for a rough surface.

that being said, a smooth surface is the easiest from which to pull parts as the resin has the least amount of surface area to hold onto.

Lastly, epoxy resin can have the same “glossy finish” as polyester, however, most epoxies are not UV-stable, either needing a stabilizing agent, or a suitable clear coat to block the degrading UV rays

#5

Thanks. What sort of clear coat do I use, how do I apply it? As I said before, my friend used some clear coat in a can and said it is peeling off now. Maybe he applied it wrong.

#6

Thanks. Do you have any suggestions for something as easily accessible as waxpaper, but glossy, which I can use to line my MDF “mold”? Also curious how to use a stabilizing agent or clear coat as you mentioned.

Thanks again.

#7

mylar film, like heat blankets? That’s all I can think of. why not make a proper plug and paint it with duratec (check the supplier’s sticky post to find it) polish and such!

#8

Can someone elaborate more on this? Any experiments or tests been carried out on this to prove it? Also lastly how much weaker/stronger are we talking about here? In terms of tensile/compressive/shear/torsion stress MPa etc…??

#9

The strength of a composite part comes from the many different directional layers of the reinforcement and very little with the binding agent (Resin).