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Clear Coat Over Carbon

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Clear Coat Over Carbon

06 Jun 2011 13:02

The clear coat on the carbon bits of my bike is starting to crack and come off in patches. I should get a new bike because I really deserve it. In the meantime should I do something to the bad clear coat? Like scrape it all off and re-coat it? If so with what do I coat it? Is it just a cosmetic problem or does the carbon NEED to be protected?

wondering what to do
User avatar rickshaw
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06 Jun 2011 13:45

buy some polyurethane, coat it, and then sell the bike on ebay to some sucker

next time get titanium. I got mine in '97 and it looks like the day I bought it.
User avatar Zigster
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06 Jun 2011 16:38

rickshaw wrote:The clear coat on the carbon bits of my bike is starting to crack and come off in patches. I should get a new bike because I really deserve it. In the meantime should I do something to the bad clear coat? Like scrape it all off and re-coat it? If so with what do I coat it? Is it just a cosmetic problem or does the carbon NEED to be protected?

wondering what to do


Why don't you ask the manufacturer what to do since it's their bike?
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06 Jun 2011 17:20

TERMINATOR wrote:Why don't you ask the manufacturer what to do since it's their bike?


Let me tell you what they'll say. "Buy another one of our bikes!"

You could try to argue material defect if the frame set is in warranty. But, it would take a benevolent company to grant the warranty replacement.

A carbon bike frame should never be expected to last as long as an alloy frame. Mechanically current carbon designs are superior to alloys in almost every way. No question. It seems to me carbon frames don't stand up well at all to forces outside the design scope. Alloy frames do much better in this regard.
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06 Jun 2011 18:10

In which point is the clear coat coming off?
If it's some junctions area it might be the frame cracking under it.
If not, it's just cosmetic.
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User avatar Michele
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good tips

06 Jun 2011 21:55

Image

zig: The same bike for 14 years? No thanks. My high sense of moral superiority to everyone else prevents me frrom ebay dumping. even suckers are people.

term: the MFG would be a good source. I didn't think of that. may try

dw: the bike is 6 years and I don't exactly baby it. ride in rain, snow, road salt is the most likely culprit, or maybe some cleaner where I didn't read the label, solvent sppatter from chain... could have been anything, but whose fault?

michele; I didn't think to check for cracks, I did. none found. As long as its just cosmetic, its just another reason to get a new bike.
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06 Jun 2011 22:30

rickshaw wrote:Image

zig: The same bike for 14 years? No thanks. My high sense of moral superiority to everyone else prevents me frrom ebay dumping. even suckers are people.

term: the MFG would be a good source. I didn't think of that. may try

dw: the bike is 6 years and I don't exactly baby it. ride in rain, snow, road salt is the most likely culprit, or maybe some cleaner where I didn't read the label, solvent sppatter from chain... could have been anything, but whose fault?

michele; I didn't think to check for cracks, I did. none found. As long as its just cosmetic, its just another reason to get a new bike.


Where on the bike is that? Seat stays, chain stays or front fork? Anyway, in the picture on the righthand side about halfway up there is some clear cloat sticking out like mount Fuji and right next to is a whitish "ridge line" that extends all the across and terminates into a "cove" of weathered clearcoat. It looks like there has been some deformation there. But it's hard to tell from the blurry photo.
Elagabalus
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07 Jun 2011 01:08

It looks fine! (not being sarcastic).

I'd get some super fine sand paper and remove any flaky stuff, cleaning it up and then clear coat it and ride it another 6 years. Its already a rain bike so even if you are the worse clear coat painter it should still look fine.

I know the carbon witch hunters will come out of the woodwork but you are currently riding it and it fine other than the cosmetic issues, its not like you feel the bike is all squishy as you ride it so its not going to be any worse than it is now.

Keep it as your backup bike, rain bike, turbo trainer bike or just emergency bike when your new bike is having any issues is better than sitting at home if you do need another bike.

Almost forgot, I have a 11 year old carbon bike that's a backup bike, for a while I fell for the carbon witch hunters but I rebuilt it and ride it anytime I need or want and its still great.
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User avatar ElChingon
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07 Jun 2011 03:51

Wet and dry on a warm day then buy a quality tin of acrylic clear coat and spray it .

It will last 12 months after which you need to do it again or buy a new one.

Make sure the frame is dry inside and out.
You can spray away cracks in bars and seat posts as well. but it wont last long.

Time for a new one soon
brianf7
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07 Jun 2011 04:11

just a thought,

when spraying with polyurethane, make sure it is above 50 degrees, on a day with no humidity.

if not, then you will be spraying milk.


made this mistake more than once.
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User avatar tubularglue
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07 Jun 2011 05:20

DirtyWorks wrote:Let me tell you what they'll say. "Buy another one of our bikes!"

You could try to argue material defect if the frame set is in warranty. But, it would take a benevolent company to grant the warranty replacement.

A carbon bike frame should never be expected to last as long as an alloy frame. Mechanically current carbon designs are superior to alloys in almost every way. No question. It seems to me carbon frames don't stand up well at all to forces outside the design scope. Alloy frames do much better in this regard.


I'm not sure what frame material has to do with paint coming off. I've had alloy frames that have trouble with paint delaminating. It would appear to me that the process used and or paint is far more important that what it's covering.
richwagmn
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Thanks for the inputs

07 Jun 2011 11:56

This situation has got me thinking. Why clear? I'll never be make it look "good as new" so why not pick a color. I could go crazy with color. Thinking is good.

rich: agree. not what you do, but how well you do it.

BTW I have read a few places that carbon fiber dust has been implicated in health issues so I think wet sanding is the way to go. Now I have to find the time.
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07 Jun 2011 12:08

dip it in Gold, cause the price per ounce is falling :D


money on the return, yo'
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User avatar tubularglue
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10 Jun 2011 02:40

Unless you leave your bike in the sun all the time, it's really just a cosmetic issue.

What I've done with quite good results on carbon stays and forks that looked like yours is to clean off all of the delaminated clear coat (chip off whatever comes off easily and whatever is delaminated) and then lightly sand around the edges of the clear coat with fine sandpaper or steel wool (220 grit or higher). The goal is to remove the loose and peeling clearcoat, and rough up the area around it so that the new finish can adhere well.

Once you've got the ugly bits removed and sanded, clean the whole area with alcohol or acetone, mask off the areas you don't want oversprayed and then spray it with a can of lacquer. I've used Deft Satin spray lacquer with great success.

With a bit of practice, you can get something that looks waaay better than it did before. Maybe not as good as new, but for a few dollars and some time, you'll be happy with it.

Don't sand the carbon much at all, just enough to get some light surface roughness. And, it's always a good idea to wear a dust-mask or a respirator when sanding anything. Especially carbon.

This method also works well for banged up Campy carbon brake levers.
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Many thanks!

10 Jun 2011 11:38

fishtacos wrote:Unless you leave your bike in the sun all the time, it's really just a cosmetic issue.

What I've done with quite good results on carbon stays and forks that looked like yours is to clean off all of the delaminated clear coat (chip off whatever comes off easily and whatever is delaminated) and then lightly sand around the edges of the clear coat with fine sandpaper or steel wool (220 grit or higher). The goal is to remove the loose and peeling clearcoat, and rough up the area around it so that the new finish can adhere well.

Once you've got the ugly bits removed and sanded, clean the whole area with alcohol or acetone, mask off the areas you don't want oversprayed and then spray it with a can of lacquer. I've used Deft Satin spray lacquer with great success.

With a bit of practice, you can get something that looks waaay better than it did before. Maybe not as good as new, but for a few dollars and some time, you'll be happy with it.

Don't sand the carbon much at all, just enough to get some light surface roughness. And, it's always a good idea to wear a dust-mask or a respirator when sanding anything. Especially carbon.

This method also works well for banged up Campy carbon brake levers.


This is good info...
I knew SOMEBODY out there has had the same experience. I wasn't sure if acetone would be a solvent for whatever holds the carbon composite together. Do you know if off the shelf paint stripper, the methyl chloride variety, is harmful to carbon composites?

if I make it look too good the wife may not understand the need for a new bike...
User avatar rickshaw
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13 Jun 2011 05:02

Paint stripper and other solvents shouldn't harm the epoxy, but they may affect the clear coat that's not damaged. I would test the stripper or any other chemical on a small area of the clear coat that's damaged to see what happens.

If you just need to clean the dirt/oil/sanding dust from the area before you spray it, then you can just use denatured alcohol or even rubbing alcohol and a clean, lint-free rag. They're easy to find chemicals and relatively non-toxic.
fishtacos
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15 Jun 2011 09:08

In theory methylene chloride paint-stripper shouldn't be a problem but I wouldn't suggest you use it. Just sand the loose material back to smooth edge. You can patch this in and sand smooth. Then coat the whole tube with new varnish. Out a spray can or you can go to a yacht chandlery and buy a can of 2pack polyurethane. You can brush this on.

The varnish comes loose over time because it gets chipped, water gets under, adhesion on frame was never that great as new and years later it starts to come loose. It is not problem for frame underneath.

There is no way a supplier will take any notice cos he will blame it on chipping from stones (read your small print - for cars also)

I've seen big problems with the old giant cfr frame where the alloy tube is fitted into end of carbon. People forget the carbon conducts in relation to aluminium.

Ps I am yacht painting cyclist. We paint carbon on big scale:)
messycolin
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Speaking of Yacht paint...

30 Aug 2011 07:18

Why not use a 2 part polyurethane based yacht clear coat after you wetsand and prep the surface of the carbon. If you use the "roller and tip" technique you should get a smooth stroke free glossy clear coat finish. 2 part poly yacht paint is about as strong and chip resistant as you can get in a paint. Or maybe instead of using a clear coat go for a midnight black gloss finish. Kinda like the Cervelos, paint the stays/fork jet black. That would look unique and Fcuking cool!!! :D
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