Is Sunlight bad for carbon fiber?

I've gotten into the habit of popping the engine cover after returning home from a "spirited" drive, as the engine is so hot. However, my garage faces south, so that means the carbon fiber engine covers are in the sun unprotected.

I'm wondering if there is a UV protectant on them? I really hope the carbon roof has a UV protectant.

I've seen many pics of Porsche Carrera GT's that have had their carbon fiber turn green over the years because of sun exposure. Just wondering if that is a concern.

Read this:

http://me.eng.sunysb.edu/~compmech/downloads/N29.pdf

Heavymetals said:

Read this:

http://me.eng.sunysb.edu/~compmech/downloads/N29.pdf

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Oh thanks! Can't wait for my next flight on a 787

Yes. Uv light deterators carbon fiber and the resin matrix.

So sunlight is bad for carbon fiber.

What about the carbon roof? I would think that it would have some UV coating on it?

Axxlrod said:

So sunlight is bad for carbon fiber.

What about the carbon roof? I would think that it would have some UV coating on it?

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They should have a Uv coating yes. However I know the Acura NSX has a “dry” carbon roof and package. The term dry typically refers to prepreg but has been much misused as a marketing term recently with people falling victim to some calling their items dry but not adhering to the use of prepreg. But typically there is a matte finish which the people say is dry.

I would assume Acura uses prepreg since it’s readily available now even for hobbyists to use since there’s out of autoclave now. However I’m unfamiliar with their finishing process. There’s a few ways to make it look “dry” or matte and there are special flattening agents for clear coat.

One way to tell is take a paint gauge thickness reader for clear coat. If it shows there’s a topcoat then you are fine. If not then there’s nothing there. Also you can tell by running your fingernail on top or just tapping it since parts with and without clear will act differently and sound different. This also goes for parts that are resin rich vs resin starved as a quick test without clear.

Axxlrod said:

So sunlight is bad for carbon fiber.

What about the carbon roof? I would think that it would have some UV coating on it?

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I would avoid parking outside under the sun for days on end.

Yes. In time they will all discolor.

I would imagine there is a clear coat on the carbon fiber to protect against UV. Just how long it last it another question.

Supposedly manufacturers coat "bare" CF panels with a UV resistant coating.
In the early days on Porsche Carreras that coating yellowed but protected the base CF IIRC. Big to-do at Porsche !
I'm sure Honda has its act together but an email to the engineering department might make you sleep better