removing clear coat from carbon fiber

[rtrocket59]

Sooo today I let my buddy redo my carbon fiber hood. When I got the car back, it looked like he just sprayed clear coat over the previous layer (original layer that was spotting/pealing). So now I decided that I wanna do the work myself. Does anybody know how to remove several layers of clear coat with out ruining the bare carbon fiber? Thanks for the help!

 

[4g63tc]

Go to a local autobody,a nd supply place, get a 3m trizact 6" mounting disc, and 400, 800, and 3000 grit finishing pads, and use generous amounts or water. Take your time.

 

[XTurbodTalonX]

I would personally sand it down by hand. I prefer to have a hose running over the surface I'm sanding. It helps to clean the sand paper and keep it 'sharp'. Hoods are relatively flat. You'll know when you go from removing clear coat to actually removing hood material. You don't really give a crap about the clear coat, use an aggressive grit to get rid of it. You do, however, care about the hood itself. Once you're sanding the actual hood, use a much less aggressive grit and get her nice and smooth. It will look kind of cloudy, but once that new clear coat hits, it will look like water. Why did your buddy just clear right over the old stuff without sanding? I'm an auto paint rookie and I know that is a no no.

 

[bigbird94]

These guys already answered it pretty well here for you. Just take your time!

 

[ed1380]

I would personally sand it down by hand. I prefer to have a hose running over the surface I'm sanding. It helps to clean the sand paper and keep it 'sharp'. Hoods are relatively flat. You'll know when you go from removing clear coat to actually removing hood material. You don't really give a crap about the clear coat, use an aggressive grit to get rid of it. You do, however, care about the hood itself. Once you're sanding the actual hood, use a much less aggressive grit and get her nice and smooth. It will look kind of cloudy, but once that new clear coat hits, it will look like water. Why did your buddy just clear right over the old stuff without sanding? I'm an auto paint rookie and I know that is a no no.

so its ok to sand the actual carbon fiber? will it mess up the finished look at all?

 

[rtrocket59]

I would personally sand it down by hand. I prefer to have a hose running over the surface I'm sanding. It helps to clean the sand paper and keep it 'sharp'. Hoods are relatively flat. You'll know when you go from removing clear coat to actually removing hood material. You don't really give a crap about the clear coat, use an aggressive grit to get rid of it. You do, however, care about the hood itself. Once you're sanding the actual hood, use a much less aggressive grit and get her nice and smooth. It will look kind of cloudy, but once that new clear coat hits, it will look like water. Why did your buddy just clear right over the old stuff without sanding? I'm an auto paint rookie and I know that is a no no.

Seems like this is what I'm going to do! And he just started working at a body repair shop so he thought he knew what he was doing haha

 

[SrKegler]

Chances are you will hit the carbon fiber.

Log on here and ask the experts. First use their search, probably not the first person repairing carbon fibre mess ups.

autobody101.com

 

[4g63tc]

so its ok to sand the actual carbon fiber? will it mess up the finished look at all?

If you Cut into the weave, yes it will damage the Carbon Fiber, but most gelcoat topcoats are thick, and you would really have to sand alot to get through it.

 

[rtrocket59]

after wet sanding, i've realized that the spots on my hood was just from cooked wax. i sanded with 400 grit for about 4 hours and the wax is still there!!!!!

 

[4g63tc]

Post some Pics, of what you have done already. Dry ofcourse

 

[rtrocket59]

first one is after wetting and drying off. second is after wetsanding, spraying down, and letting dry off

 

[SrKegler]

First of all get some wax and grease remover and clean the hood good. While you're sanding you're pushing the wax into the sand scratches.

Looks like you are just randomly sanding a section at a time. Use a sanding block and form x"s in the sand scratches. Keep sanding until you can see the carbon fibre weave underneath then stop. What you looking for is uniformity. Looks like you've already hit the carbon fibre on the front of the hood.

I would start at the top of the hood and sand left to right, top to bottom until the weave straightens out and becomes uniform. Use plenty of water, slow and steady.

The front passenger side of the hood looks about right, still a little "wavy" in about the center part of that spot.

 

[rtrocket59]

First of all get some wax and grease remover and clean the hood good. While you're sanding you're pushing the wax into the sand scratches.

Looks like you are just randomly sanding a section at a time. Use a sanding block and form x"s in the sand scratches. Keep sanding until you can see the carbon fibre weave underneath then stop. What you looking for is uniformity. Looks like you've already hit the carbon fibre on the front of the hood.

I would start at the top of the hood and sand left to right, top to bottom until the weave straightens out and becomes uniform. Use plenty of water, slow and steady.

The front passenger side of the hood looks about right, still a little "wavy" in about the center part of that spot.

yes! i realized after that picture that i shouldnt do it randomly and started to sand with 800 grate and 2000. it looks a lot better but still needs mad work. ill clean the hood the way you described it, sand, than post some pictures on how it looks after that.

 

[4g63tc]

I can tell by the Pics, in some places you're not even through the clear yet, especially in the middle.

The haze should be uniform, darker/shiny spots shouldn't be there, if you are unsure drag a fingernail over the surface, if it leaves a mark chances are you're ok in that spot, if the line looks dashed, you still have clear on top.

Keep it at 800, I personally would have machine sanded with a DA at 400-500 grit, once you have that uniform haze, switch it up to 1200, then 1500, then 2k and above. You need to really finish out, and reduce the amount of sanding scratches.

if you are re clearing, you can quit at 1500 grit.

If you are actually thinking about polishing the gelcoat, then 3000 grit, and a good rubbing compound.

 

[ed1380]

I can tell by the Pics, in some places you're not even through the clear yet, especially in the middle.

The haze should be uniform, darker/shiny spots shouldn't be there, if you are unsure drag a fingernail over the surface, if it leaves a mark chances are you're ok in that spot, if the line looks dashed, you still have clear on top.

Keep it at 800, I personally would have machine sanded with a DA at 400-500 grit, once you have that uniform haze, switch it up to 1200, then 1500, then 2k and above. You need to really finish out, and reduce the amount of sanding scratches.

if you are re clearing, you can quit at 1500 grit.

If you are actually thinking about polishing the gelcoat, then 3000 grit, and a good rubbing compound.

which one is better?

 

[Black Widow97]

which one is better?

Clear would be best. With the uv protection sanded off, the gel coat will yellow right away. Also you will never be able to polish the gel coat to look shiny like clear would make it look.

 

[rtrocket59]

How do I remove all the wax residu after I filled in all the scratches? I've been sanding for 8 hours and it still won't come off

 

[SrKegler]

wax and grease remover. Follow the directions on he bottle. Mainly use 2 rags, wipe it on with one rag, wipe it up with the other.

 

[4g63tc]

Use TSP as a cleaner, anything else with Acetone, Mineral spirits, etc will damage the gelcoat and leave residues which will promote fisheye.

Since You are Spraying Clear over an essentially "unpainted" surface there really isn't much of a "chemical" bond that takes place, which is probably why it flaked in the first place. expect to redo the clear in 2-3 years, or sooner depending on storage.

 

[ed1380]

This seems to be the best place to post this question. My hood flew up today going 25. There's a few gashes in the gelcoat. Would I have to sand all the way down to the cf now? Or is it unrepairable?

 

[4g63tc]

This seems to be the best place to post this question. My hood flew up today going 25. There's a few gashes in the gelcoat. Would I have to sand all the way down to the cf now? Or is it unrepairable?

Post Pics.

 

[Chrispy0530]

..Just wondering, how are all of these hoods flying up?? I've heard way too many of these cases. I'm assuming they're all CF. I was wanting to go with a CF Hood, paint it to match my OEM color. Haven't done so yet just because of the fact that I don't want to have to put Hood Pins. No Hood pins = Flying hoods?

 

[rtrocket59]

Use TSP as a cleaner, anything else with Acetone, Mineral spirits, etc will damage the gelcoat and leave residues which will promote fisheye.

Since You are Spraying Clear over an essentially "unpainted" surface there really isn't much of a "chemical" bond that takes place, which is probably why it flaked in the first place. expect to redo the clear in 2-3 years, or sooner depending on storage.

Soo don't use anything with acetone? And what's tsp?

 

[4g63tc]

Soo don't use anything with acetone? And what's tsp?

Yep, Acetone will actually soften, and degrade Fiberglass, and gelcoats.

TSP is available, at any Lowes, Home depot, etc. Usually found in the paint department.
oh yeah, Tri Sodium Phosphate, also if mixed with Talcum powder into a thick paste removes oil from driveways.

@ Chrispy Hood Pins are recommended, since most of the time the hood latch is just "glassed" in, and through constant vibration, exposure tot he elements, delamination can occur, leading up to catastrophic failure. It doesn't happen to everyone, but a few dollars spent on hood pins, saves bodywork, and busted windshields later.

 

[ed1380]

Post Pics.

the thick line actually broke the carbon fiber and fiberglass underneath. but at both parts you can see the spiderweb of glaze cracking

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