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the fat kid
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Discussion Starter · #1 ·
A buddy of mine is piecing together some steel hotness and got a smoking deal on an ugly puke rainbow carbon front fork. our first impression was to strip that thing down to the carbon.

Now, here's the question; Whats the "proper" way to do this? How are carbon forks generally constructed? I'm going to assume that there is the carbon base weave, then it baked in gel coat, and then it having final prep and paint. Am I close? I'm thinking some lacquer thinner in a small discreet spot for a test run... thoughts?
 

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Well,, I'm not sure about stripping protocalls for CF, but what if you just sand the surface of the paint that's already there, and paint over it? If the old paint is in good shape you'll be fine.
 

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Visitor302 said:
Well,, I'm not sure about stripping protocalls for CF, but what if you just sand the surface of the paint that's already there, and paint over it? If the old paint is in good shape you'll be fine.
That's what I was first going to suggest, but re-reading his post I think they are looking for a bare carbon look.

I'd be very leary of taking any kind of strong solvent (lacquer thinner is potent stuff) to a part made of fiber-reinforced plastics, unless I knew for sure that the solvent would not damage whatever resin it came in contact with. Not knowing what those various layers are, or how deep they are, it seems like there's a chance of causing damage to the matrix. Not something I'd want to mess with on a fork.

If it were me, I'd forget about naked carbon and just paint it to match (or contrast with) the frame. .wash, sand lightly, prime, paint.

Maybe some composites expert here has better advice. With enough testing I'm sure it could be done safely, but not economically. I've read about restorations of old oil paintings in which they take a tiny core sample, do chemical analyses of all the layers of various varnishes, and then devise a solvent formula for each layer, so they only attack one layer at a time. It takes years, and costs millions.
 

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Working with and painting carbon is similar to fiberglass. Just gently wet sand (400-800grit) it down till the paint is gone then layer on your paint base. Go over that with four/five layers of a good UV clear sanding between (layer 1K/1.5K/2Kgrit). When sanding, stop soon as you can see the bare carbon. There is very little depth between paint base to carbon. I also use a cut and polisher combo with a polishing rag, such as System 1 to finish off the clear and make it purty and shiny.

Go to an auto paint supply shop for the paper, clear coat (U-Pol #1 clear) and also ask about tips for painting in general if you're new to it. Btw, this will take a bit of time as well as huffing a bit of chemicals and powders, a mask is good to have.
 

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thesmokingman said:
Working with and painting carbon is similar to fiberglass. Just gently wet sand (400-800grit) it down till the paint is gone then layer on your paint base. Go over that with four/five layers of a good UV clear sanding between (layer 1K/1.5K/2Kgrit). When sanding, stop soon as you can see the bare carbon. There is very little depth between paint base to carbon. I also use a cut and polisher combo with a polishing rag, such as System 1 to finish off the clear and make it purty and shiny.

Go to an auto paint supply shop for the paper, clear coat (U-Pol #1 clear) and also ask about tips for painting in general if you're new to it. Btw, this will take a bit of time as well as huffing a bit of chemicals and powders, a mask is good to have.
+1

Lots of wet sanding with high grit paper. Its just about impossible to get the mirror finish you see on a new fork, but you can still get an interesting texture.

Unfortunately, if the fork was completely painted, its very likely that they didn't put a cosmetic layer of carbon into the layup. So you might never see that carbon weave that you're expecting.
 

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the fat kid
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Discussion Starter · #6 ·
well, we did end up starting with some 400 and grading down to 1000. we tried a little spot with the lacquer and it was not even budging, so we went right to the wet sanding. It actually came out pretty nice.. as soon as you could see the carbon, we fine'd it out and it looks pretty rad. I'll have to see if he took any pics.
 

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Formosan Cyclocross
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If the cost of removing the paint is less than a new fork... Calfee offers the service following a full inspection. I don't know how much $$$ though.
 

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DRY sanding....

You can wet sand if you want, but there is a faster way. I've sanded a lot of carbon components lately. Most were just clearcoated with graphics under the clearcoat, that I wanted to remove.

Use Norton 3X sandpaper, available at Home Depot and probably any place sells a decent amount of sandpaper. I wouldn't use any coarser than 220 and I would switch to 320-400, just as the carbon starts to show through the paint. There is no need for 600 of finer, prior to clear coating, unless it's just used briefly.
 

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'brifter' is f'ing stupid
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JCavilia said:
I'd be very leary of taking any kind of strong solvent (lacquer thinner is potent stuff) to a part made of fiber-reinforced plastics, unless I knew for sure that the solvent would not damage whatever resin it came in contact with. Not knowing what those various layers are, or how deep they are, it seems like there's a chance of causing damage to the matrix. Not something I'd want to mess with on a fork.

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lacquer thinner won't harm carbon a bit. the cervelo guys talk about solvents and carbon at brain bike...we use lacquer thinner on carbon rims all the time, for cleaning prior to gluing tires.
 
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