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  1. #1
    serenity NOWWW! amahana1's Avatar
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    Painting carbon fiber

    Can carbon fiber be stripped of its clear coat in order to paint it a different color? Dont really like the carbon fiber weave look and want to paint it a solid black. Its the fork by the way.
    In his surreal surroundings among the clouds, this was his flight! Until, he saw the master caution light.

  2. #2
    Senior Curmudgeon
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    I think you don't want to strip the clear coat completely.. Might open the carbon fiber underlay to damage. I think the clear coat is also structural, holding the fiber in place, but I may be wrong..

    You also open yourself to some risk by painting. If the frame develops cracks, the paint may hide them. When carbon cracks, I understand that it (like aluminum) can then fail quickly ("catastrophically").

    So my answer (admittedly one uninformed by personal experience in painting carbon fiber), is that "yes, you can probably roughen the surface lightly and then paint, but there are negatives to take into account." I'm sure that others with more experience in this area will reply. I look forward to hearing what they have to say.

  3. #3
    Senior Member mtbikerinpa's Avatar
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    Unlike metal finishes, carbon clearcoat should not be removed to paint it. The Gelcoat is an important part of the material and seals it from abrasion and weather.
    To promote adhesion, however, you will want to remove the gloss from said finish. Do so with caution and medium to fine grit; ie 320 or higher and wet it as you go. Stop when it is evenly hazy. At no point should the surface get rough or weave expose, as this means you went through the afore mentioned coat.
    Go to an automotive supply store(NAPA) and get a can of urethane primer. It will run about 16 bucks for a spray can, but it goes a long way and has many advantages in this job. Mainly the fact it builds up. Spray two coats with dry time between, then let it dry for a day. Sand lightly with 320-400 grit to smooth it. Tack-rag it off to remove the dust, and paint as you feel fit.

    (DISCLAIMER)
    All urethane products, primarily those sprayed, should be used in GOOD VENTILATION and user should wear the appropriate filtration mask. Details are available at the supply store. It is simple to use, but as with any paint product, should be treated with propper cautions.
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  4. #4
    Senior Member mtbikerinpa's Avatar
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    On the subject of frame failures. Carbon has a sharp failure mode when abused. When it has reached its ultimate load it will crack, but these cracks are generally apparent even through paint. Delamination of the weaves within a tube would be harder to detect and are more of a risk to find, however they are not generally hindered by a finish, since carbon is not transparent.
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    Senior Member sydney's Avatar
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    Quote Originally Posted by FarHorizon
    I think the clear coat is also structural, holding the fiber in place, but I may be wrong..

    You also open yourself to some risk by painting. If the frame develops cracks, the paint may hide them. When carbon cracks, I understand that it (like aluminum) can then fail quickly ("catastrophically").
    You are wrong about the 'structural' aspect. Also,ompanies have been painting CF frames for years, but the catastrophically exploding CF myth will never die.

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    Question for mtbikerinpa...
    I have a Trek 2300 that has the clear coat peeling. I scraped the peeled clear coat off with an exacto knife and I'm litely sanding the rest. Can I just spray a lacquer clear coat on or do I need to primer first with a eurethane primer?
    Thanks...

  7. #7
    Senior Member Nessism's Avatar
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    Most carbon parts have a clear coat (paint) on top of the gel coat (structural epoxy holding the fibers in place).

    In either case, painting is no problem. Rough up the existing finish with 400 wet paper and lay down a sealer coat of your choosing (I used PPG DP Epoxy when I painted my Look HSC3 fork). After the sealer coat, spray your color and clear per normal.

    Good luck.

    Ed

  8. #8
    serenity NOWWW! amahana1's Avatar
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    excellent. thanks for the help everyone!
    In his surreal surroundings among the clouds, this was his flight! Until, he saw the master caution light.

  9. #9
    I drink your MILKSHAKE Raiyn's Avatar
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    Quote Originally Posted by amahana1
    Dont really like the carbon fiber weave look
    You'd think that for most people that would be the whole point of getting Carbon Fiber

  10. #10
    serenity NOWWW! amahana1's Avatar
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    Quote Originally Posted by Raiyn
    You'd think that for most people that would be the whole point of getting Carbon Fiber
    For most but not all....I really like the way carbon feels, but want a solid color to go with the rest of my solid color bike...black. The carbon weave that is visible on the fork looks out of place with the rest of the bike.
    In his surreal surroundings among the clouds, this was his flight! Until, he saw the master caution light.

  11. #11
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    Isn't the epoxy used with carbon degraded by uv light? Not a problem if you are going to paint a solid colour but if you are planing to clear coat a peeling frame it might be something to look into.

  12. #12
    Senior Member mtbikerinpa's Avatar
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    Essentially all finishes are degraded by UV. It is merely how much and how fast. A pigmented topcoat(not clear) will last longer than a clear to be sure, but a quality gelcoat should still last years before it becomes an issue.
    Laquer clear should be avoided if you can help it. The higher volatility of the laquer solvents can damage the gelcoats in some instances. Not always, but it can and it would really be a bugger to find out That is the purpose of using a urethane finish. Urethane is non reactive to the materials it is applied to, not to mention it is wayyyyy more durable. I know it costs more but it is worth it.
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  13. #13
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    On this subject. Is there any problem using acrilic auto paint on carbon fiber parts?

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    Sooo... If I like the looks of the fiber weave, can I just spray Urethane primer on it and leave it, or do I need to spray a top coat on the primer, or can I spray only a Urethane clear coat with no primer? Sorry for my confusion on this, I just want to get it right the first time. I'll be moving to the the Gulf Coast soon so I want the frame to be well protected from the elements.
    Thanks for all the help, I really appreciate it...

  15. #15
    Senior Member mtbikerinpa's Avatar
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    Urethane primer will typically be in ship gray, red-oxide, or black. You can use clearcoat over the material directly, provided you clean it perfectly of any contaminants. Acrylic is also non-reactive. In fact, Acrylic-urethane is a commonly available automotive finish. It posesses most of plain urethane's durability but with some different propperties of acrylic. Straight acrylic will work on the application, but do not be lured into cheaping out, as it will potentially haunt you later. Pay more now and save for the life of the frame(A/U is a 10-15yr life expectancy when continually outdoors.
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