Carbon fiber yellowing

[Subiepwr]

Hello everyone

I have a carbon fiber hood that started to yellow out I've seen alot of articles how you can't Buff out the yellow on the clear but I heard that meguiars has done some pretty good job on carbon fiber! I have tryed basicly everything that I can pick up at your local auto store but nothing has work ! Can anyone help please !

[corolla619]

Re: Carbon fiber yellowing

sorry, you're out of luck. the yellowing is in the gelcoat. the reason it yellowed is either poor gelcoat with little to none uv inhibitors or lack of care to the hood. i have worked with alot of carbon fiber, from molds, to over lays etc. i have 2 c/f hoods, trunk, and rear window spoiler, oh and a grille on my car. the best thing i can tell you is if you invest in another hood....take real good care of it and buy from reputable companies. ie: vis, carbon creations, seibon.

[Mike Phillips]

Re: Carbon fiber yellowing

I think I got a PM or E-mail from you about this?

Sorry if I haven't got back to you, I can's keep up with the forum let along e-mails and PM's and priority always goes to the forums...

Check out the threads in the link below as the topic of two types of Carbon Fiber components is discussed at length somewhere in them...

http://meguiarsonline.com/forums/tags.php?tag=Carbon+Fiber

If in fact the polyester or epoxy resin has turned yellow under the clear, then it's probably a discoloration throughout the matrix of the resin and cannot be fixed.

When it comes to discoloration, only topical defects, that is a problem on the surface can be fixed because you cannot work inside the coating, only on the surface of the coating.

There are some amazing before and after pictures in the threads linked to in the link above.

[roushstage2]

Re: Carbon fiber yellowing

There was also the one thread about the Porsche guys I think filing complaints or something like that, but it was said that carbon fiber will turn yellow eventually since it is supposed to be painted anyways. It would be good to find that thread.

[Subiepwr]

Re: Carbon fiber yellowing

i called VIS the company that sold me the hood they said i could try to polish the hood witch i did on the scoop most of the yellowing came out but the a week later it started to yellow a little bit again so im going to wait till i order some more stuff from a meguiars to see if it works they told me that it does have 4 layers of clear coat so i think its gonna be the clear coat yellowing. before i try all these compounds ima go this saturday to one of the classes.

[Murr1525]

Re: Carbon fiber yellowing

The classes will always help...

[Michael Stoops]

Re: Carbon fiber yellowing

It seems most carbon fiber aftermarket parts have a fairly simple and straightforward epoxy coating that lacks any (or much) UV inhibiting components. Generally these parts are sold in a fairly raw state, meaning that they are intended to be painted rather than left exposed. It's not terribly different from buying an aftermarket steel or aluminum hood, or other part - they may be primed but they aren't really "ready to go", so to speak.

The lack of UV inhibitors will cause the epoxy coating to yellow over time and unless you sand it down and recoat it, which isn't quite the same as doing this with traditional paint, you may not be able to do a heck of a lot with it.

When acquiring a carbon fiber body panel that you plan to keep naked so as to display the carbon weave, it's best to at least have it shot with a good automotive clear coat as these will contain UV inhibitors that will protect the finish. Even looking at a well built race car, where the cost of carbon fiber parts is generally much higher than what the typical consumer would pay, those parts will yellow over time if they are left exposed. Of course, on a true competition car they won't bother painting many of these pieces merely to save weight, and they don't care if the parts yellow or not. They just have to be lightweight and function reliably.

[Andycampero]

Re: Carbon fiber yellowing

Wow so once a carbon fiber hood or trunk good yellow it's not fixable!!! I'm bumed out

[hacker-pschorr]

Re: Carbon fiber yellowing

GM spent a small fortune coming up with a UV coating to protect the carbon panels on the ZR1. Per the guru's the UV protectant costs $60,000 a gallon and they are not sharing the formula. Clear already mixed with the protectant is $2k a gallon (not bad compared to some exotic paints).

IMO this is pretty impressive from GM considering Porsche didn't go this far since Carrera GT owners are complaining about yellowing panels:

http://forums.rennlist.com/rennforums/carrera-gt/364648-yellowing-carbon-fiber.html

If you fast forward to post #255 there are photos of the CGT Prototype Jerry Seinfeld owns that is also yellowing.


Per Porsche, this is perfectly normal: