Carbon Fiber Repair? [Merged 12-7] CF hood

[eclipsegs98911]

Tonight I went to close my hood and pressed to hard causing the Gel Coat on my carbon fiber hood to crack. Nothing is wrong with the weave itself, just the gel coat. Does anyone know if the cracks are fixable? I am not willing to buy another hood because this one is now my 4th one. I want it mainly for weight reasons, the only fix i can come up with is paint it or possibly use the stuff you fix cracked windsheilds with, but i am afraid to try it.

 

[i1nk83]

you can fix it with fiberglass resin. and if you real neat and carefull you wont hardly notice it

 

[yoshimitsuspeed]

It would be a lot easier to fix if you want to paint it afterwards

 

[steve]

I don't think the clear coat on carbon body parts is actually a gel coat but I guess that depends on the process used to make it. Usually a gel coat is a pigmented version of the same resin used to lay up the carbon or fiberglas, that is applied to the mold first and allowed to gel before starting the lay up. I was under the impression that the top coat on most carbon hoods was a UV protecting and cosmetic clear coat paint applied after the part was pulled.

If that's what it is a body shop should be able to refinish it. If it's truely a gel coat of epoxy or polyester resin then is going to be a little more difficult to correctly repair. Check with the people who made or sold it.

Steve

 

[yoshimitsuspeed]

I don't think the clear coat on carbon body parts is actually a gel coat but I guess that depends on the process used to make it. Usually a gel coat is a pigmented version of the same resin used to lay up the carbon or fiberglas, that is applied to the mold first and allowed to gel before starting the lay up. I was under the impression that the top coat on most carbon hoods was a UV protecting and cosmetic clear coat paint applied after the part was pulled.

If that's what it is a body shop should be able to refinish it. If it's truely a gel coat of epoxy or polyester resin then is going to be a little more difficult to correctly repair. Check with the people who made or sold it.

Steve

There is clear gel coat and although it is the same basic thing as laminating resin it's properties are a little different. Laminating resin is designed to flow and penetrate the fabric, gel coat will hold it's shape better(I belive it's called a higher thixotropic rating).
If you spray laminating resin 1/8 inch thick on a horizontal surface it will run into a big puddle on the floor. Gel coat will hold it's position.
It could be gell coat or laminating resin on the surface but it has to be one of those. If it was just a thin layer of paint you would be able to completly see the texture of the weave on the surface.
The way we fix fiberglass is to take a die grinder with a small metal burr and grind a small valley down the length of the crack then fill it with the same gel coat the part is made of. When you fill it in you want to make sure the gell coat is higher than the surface of the part. Once it's cured sand it smooth up to 1500 grit and buff. Now this is for pigmented gel coat which can make very clean patches since it covers up underneath imperfections. The problem with clear is either you dont grind all the way down to the fabric and fill it in, in which case the crack will still be visible under the patch. Or you grind down to the fabric ( as long as you don't go too deep this is not structurally damaging) you damage the weave which will be visable through the patch.

 

[tsiawd3]

hi. i recently purchased a slightly oxidized carbon fibre hood.
i was wondering if anyone knew any way to polish it to make it have a like new finish

 

[g_ferg]

hi. i recently purchased a slightly oxidized carbon fibre hood.
i was wondering if anyone knew any way to polish it to make it have a like new finish

Buff the clear coat.And i would recommend having someone else do this if you have never done it.

 

[silver bullit]

Could you just wet sand it with 800 or 1000 maybe 1500 grit sandpaper then re-clear it?

 

[g_ferg]

Could you just wet sand it with 800 or 1000 maybe 1500 grit sandpaper then re-clear it?

I have never tried to re-clear anything before. Is it actually that hard to do?

 

[silver bullit]

Its like painting a car with clear coat or applying clearcoat to car that has been painted. Its not that hard if you know what you doing and you have a garage to paint it and prep the car/part well.

 

[g_ferg]

Its like painting a car with clear coat or applying clearcoat to car that has been painted. Its not that hard if you know what you doing and you have a garage to paint it and prep the car/part well.

well i understand that part. Just the detailer where i use to work told me you had re-spray the entire car base and clear. Thats why i was curious if just scuffing up the clear with something that fine and respraying it would work.

 

[silver bullit]

well i understand that part. Just the detailer where i use to work told me you had re-spray the entire car base and clear. Thats why i was curious if just scuffing up the clear with something that fine and respraying it would work.

Your not scuffing it up if you wet sand with a high number grit sand paper.

 

[4G63_Attack]

You can try to polish the hell out of it, that should help. Using a buffer machine can cut the time in half instead doing it by hand. Once its done you can clear bra the whole hood to protect it.

 

[h8r]

If you are going to try this, I would pick up a porter cable polisher

 

[silvreclips]

Just pay someone to reclear the hood, it shouldn't cost that much.

If you do it yourself good luck. Its not that hard if you have all of the tools

 

[Mr Peepers]

I've had great luck with 3M rubbing compound then 3M finishing glaze/polishing compound.

Use the rubbing compound to get all the oxidation off(don't go too crazy) then the polishing compound to get the shine back. Finish up with a coat of wax. Follow the directions on the bottles and you're golden.

Me and a friend did it in under an hour by hand using microfiber rags. Much safer than using a buffer for the first time; rubbing compound is serious stuff.

 

[Project2G]

I found a post by someone on here dating back in 2004 but it may help.

There is clear gel coat and although it is the same basic thing as laminating resin it's properties are a little different. Laminating resin is designed to flow and penetrate the fabric, gel coat will hold it's shape better(I belive it's called a higher thixotropic rating).
If you spray laminating resin 1/8 inch thick on a horizontal surface it will run into a big puddle on the floor. Gel coat will hold it's position.
It could be gell coat or laminating resin on the surface but it has to be one of those. If it was just a thin layer of paint you would be able to completly see the texture of the weave on the surface.
The way we fix fiberglass is to take a die grinder with a small metal burr and grind a small valley down the length of the crack then fill it with the same gel coat the part is made of. When you fill it in you want to make sure the gell coat is higher than the surface of the part. Once it's cured sand it smooth up to 1500 grit and buff. Now this is for pigmented gel coat which can make very clean patches since it covers up underneath imperfections. The problem with clear is either you dont grind all the way down to the fabric and fill it in, in which case the crack will still be visible under the patch. Or you grind down to the fabric ( as long as you don't go too deep this is not structurally damaging) you damage the weave which will be visable through the patch.

 

[JonCgst]

I just used a scuff pad on my old one and my new one and we recleared it at our shop lightly wet sanded it and rebuffed it. Looked better than it did when I bought it. I think any painter who knows how to paint can do it. I just bought a siebon hood brand new and still recleared it(we put some paint on it). Kinda felt wierd scuffing up a new hood but like I said it looked way better than when it came from them. good luck

 

[LTUDSM]

i got some really bad clear coat and gel coat cracks in my CF Hood.i was thinking to do a wet sending,but im afraid to damage the carbon fiber material. Right now, i got one thing in my mind,What if i wet send to the carbon fiber material,and then, put a new one over the top of the old one,do couple layers of gel coat and after that couple layers of clear coat.Would it work, or do i need a new hood?

 

[XSNRGGST]

I am currently in the same predictament. I have the corners of the hood to rebuild with bondo, some huge scratches to fill and cracks to deal with. I think I am going to go the easier route and paint the hood , maybe leaving some Carbon Fiber showing with my company logo or some other original design.

I will fill you in as I do the actual work.

 

[matt98eclipse]

LTUDSM: In your case if you wanna just reclearcoat the hood, Just get some 600 grit WET sand paper and sand it down to were its a smooth non shiney look! OR you could also do is use a 6 inch DA sander with 800 grit witch is dry!!! You biggest thing to make sure is theres no shiny spots! Shiny spots will cause the clear to peel and chip easy!!

I work at a really huge body shop dealing with this stuff all day. check out my webpage for more pictures of my paintings.

 

[LTUDSM]

im talking about putting a new Carbon fiber material on top of the old one,

 

[tsiawd3]

does anyone think that turtlewax rubbing compound
then polish
then wax
would work?

 

[hedrick]

Once the resin on the original hood has cured, applying a new "sheet" is not a good idea. The new layer of Carbon will not make a strong bond to the underlying surface and surface inperfection will show through a single layer. If you do apply a single new layer, delamination of the top layer will occur. The way to fix a CF hood that has cracks and or scuffs is to have a body shop prep and spray about 3-5 layers of Clear Coat over the existing hood. After that a nice wet sand with a 1000-2000 grit sand paper and a polish will make the hood shine. I would not advise sanding with 600-800 grit sand paper because it will remove too much material and Carbon is terrible with abrasion

 

[b00sted]

Could you just wet sand it with 800 or 1000 maybe 1500 grit sandpaper then re-clear it?

You can wetsand it if the clear is thick enough.(Use ~2000 grit). It still needs to be buffed after the sanding though because it will be scratched up and hazy...The buff removes the fine scratches.