Unsuccessful Carbon Fiber Hood Restoration

[bryan5437]

I recently set out to restore my Seibon Vt-Style carbon fiber hood. According to the manufacturer it has a clear coat. The procedure I used was the following. Wash, clay, then I polished using M205 and a white pad on a random orbital buffer. I was unable to remove the cloudiness on the hood. I searched internet forums and found people had success using M49. Tried this and it had no effect. I also saw that people were wet sanding. I tried using 2000 grit on a small area of the hood. This also didn't have any effect.

For my next method of attack I was considering using M105 with an orange pad. I was hoping to get some feedback before I tried this. Can you offer me any advice?

For reference my 2004 350z Track 8/9/15 before - Album on Imgur

And 2004 350z Track 8/9/15 after - Album on Imgur

[AliusPrime]

You are going to need more power than a DA buffer IMO. Try 1500 wet sand to 3000 Trizack on a DA then follow up with some 3M Extra cut on a Foam pad and taper from there.

For all the work you are going to put into this with a buffer you may be better off to have it wet sanded in 600 and a fresh coat of clear coat done at a body shop. My shop would only charge around $300 to $350 for something like that using PPG clear.

[trashmanssd]

I have heard a lot nightmares with aftermarket Carbon Fiber hoods in a clear coat only finish. Just remember you can always get it vinyl wrapped also for 150-250 depending on finish you pick.

[bryan5437]

@AliusPrime In your opinion using a compound wouldn't be strong enough? I'm trying to do all the work on this car myself and save some money even if I lose the time.

@trashmanssd I agree with you, I've heard almost exclusively bad things about the carbon fibers hoods. This one was placed on by the previous owner and at some point I might look into alternative options like the vinyl or clear coat from a body shop like AluisPrime suggested.

[AliusPrime]

it's tough to tell. the "Clear" they use on those hoods always seem to polish out more like a resin. As much as I like the final finish of these newer water based compounds like Menzerna ans Sonax, when it comes to heavy cutting i always find more satisfaction with 3m. I also have more of a body shop background then detailing.

[Mike Phillips]

I recently set out to restore my Seibon Vt-Style carbon fiber hood. According to the manufacturer it has a clear coat.

There are two general categories of carbon fiber body panels.

Coated - Cost more and comes with an automotive style of clear paint sprayed over the components.

Uncoated - Costs less as there is no extra coat of clear paint protection. The component is ever polyester resin or epoxy and when you work on it you're working on the actual polyester resin or epoxy resin that embodies the carbon fiber material.


If the hood you're working on is clearcoated, my guess is the clear layer of paint, like factory car paint, is thin. So be careful as to how aggressive you get when trying to restore it or like the clearcoat finish on a car you can burn through it and then for the most part it's game over.

Also, treat coated components like car clearcoats, that is only use products made for car paint.


When working on uncoated components, you can use car products or more aggressive marine product but you still have to be careful because if you remove too much of the outer resin skin you'll run into the carbon fiber and then it's game over.


Normally a coated surface will get swirls just like a clearcoated car.

A non-coated or straight resin component will oxidize like a gel-coat boat.



I have a bunch of before and after pictures on MOL when I work for Meguiar's as I taught a lot of classes for the Tuner Car Clubs in SoCal and horrible looking carbon fiber hoods and wings are the norm.

[AliusPrime]

And that's why he makes the big bucks!

[bryan5437]

I called Seibon and confirmed that this hood does not have any UV protection and is Gel coated. They suggested that I wet sand using a lower grit and then polish out. It might be a little while before I give another go at it, but I will be sure to update.

[Mike Phillips]

I called Seibon and confirmed that this hood does not have any UV protection and is Gel coated.

Gel-coat is polyester resin and there is no UV inhibitors in polyester resin. This is why non-coated, polyester resin carbon fiber components and gel-coat boats oxidize when exposed to the sun and wet weather.

When they said the hood had no UV protection what they meant was the hood was not sprayed with an automotive clearcoat. The UV protection is in the clearcoat paint.

They suggested that I wet sand using a lower grit and then polish out.

When I answer a question like this I'll tend to make specific grit levels of sanding paper or sanding disc to start with and also to finish with or to avoid sanding altogether.


Did they tell you how thick the initial coats of resin are sprayed into the mold before the carbon fiber is added?

You see this is where vague advice will get you into trouble. If you sand too long with any grit level of sand paper or sanding discs or use too aggressive of a grit level, you're going to sand past the resin and hit the actual fibers that make up the carbon fiber.

If you do this, then like I said in my first reply... game over. You won't find a shop that will want to mess with trying to fix the problem so it will have become a great learning experience.

Keep in mind,

1. Sanding removes material.
2. Compounding removes material.
3. Polishing removes material.

Sooner or later... you run out of material.


Since you have M105 I'd recommend using it with a wool pad on a rotary buffer at low rpm and just buff small sections at a time and definitely clean your wool pad often using a steel spur.

Don't get the surface hot when doing this, use the technique I share here,


Fight or Flight Method for Gaging Surface Temperature


And do take good before and after pictures.

[Busy mind]

Just to piggy back on this subject, if the OP does get the hood back to OEM specs, could a ceramic coating be helpful as opposed to spraying clear? I'm sure a fresh coat of clear will last longer, but many coatings from AG are less expensive than paying a body shop.
Any bonding issues between a gel coat and the numerous coatings on the market?