Clear coat repair

Discuss light weight issues concerning road bikes & parts.
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bigskyTi
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Location: Detroit, MI

by bigskyTi

Some of the very few carbon bits I have tend to get nicked up over time and use, specifically cranks.

Since it is winter and I'm tearing the bike down anyway I thought I'd take the time to re-clear some of the bits.

What is the proper clear to use. I plan on wet sanding the parts to insure an even coat and good adheasion. I know some paints like to be baked, and since I'm only doing small parts that might be an option.

what woudl be the most durable product?

by Weenie


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Frankie - B
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by Frankie - B

If you are going the wet sanding route. you might want to try ordinary rattle can laquer. the better option is to get two component laquer at your local car painter. The latter will end up with a harder surface then the rattle can stuff.
Almost a year ago I refinished a Bontrager XXX lite stem.

Here is wat I did:

The stem is kinda hideous on its own, but with some tlc it could be turned into something nice for shure. I will replace the stock steel bolts with Ti. Then I bit the bullet and pulled out the waterproof sandpaper and a tub of water. and started the wet sanding.
The original:

Image

Midway:

Image

http://img207.imageshack.us/img207/5334/dscf0007ys3.jpg

I found out that sanding works the best underwater and, on top of that luke warm water prevents getting your hands very, very cold. ;)
After the sanding the stem was cleaned with alcohol so the laquer would adhere better. I then threaded a bolt into one of the sockets and connected a strand of rope to the bolt. This way you can hang the stem. F.I. inside a box. then just grab the moment you feel the most brave and spray!
While holding the stem by the bolt so you can rotate it to get the laquer on every spot. Do it layer by layer with 10 to 15 mins intervals. I think I gave this stem two layers.
Leave it to dry till the laquer is "touch dry" and then put it in the oven on a low temparature for ~30/45 mins to harden the paint.


ok, here are some pics of the finished product.

It has had two coats right now, It has been in the oven to help the paint cure better. Now I still need to polish it a few times with car wax. Wax on.. Wax off... the wax is basicly a way of polishing the surface.

Image

Image

Please note I did leave a small xxx lite logo on. but that is going to face the ground. I left it on so people can still see it is a simple bonty stem. (well, the big B on the faceplate is a dead give away as well...)

[edit, I just made it a sticky, because quite a lot of people ask about repainting parts.]
'Tape was made to wrap your GF's gifts, NOT hold a freakin tire on.'

foz
Posts: 151
Joined: Mon Sep 08, 2008 3:37 pm

by foz

That stem came out really well! I'm contemplating sanding down parts of my pinarello paris to remove some of the logos and then clear coating those areas again, but I'm way too worried about it turning out all wrong...

for little scratches and chips in clearcoat I use clear nail polish. Cost me 75 cents the bottle, and it fills in the chips really well with no need for sanding.

foz

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bcheung
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Location: Herndon, VA

by bcheung

Any thoughts on repairing clearcoat chips on aluminum frames?

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weenie #2533
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by weenie #2533

here is how I did my clearcoat on saddle. I stripped padding on some selle italia and sanded it nice and put a layer of black and then 3-4 layers of clear coat . 1st layer - 15min wait - 2nd layer - 20min wait - 3 layer - leave few days to dry completely.
Image

Image

Image

about cracks on alu frame I think you can sand clear coat with nice sandpaper until it get 'matte' look , than apply new layer with airbrush ...

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bigskyTi
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Location: Detroit, MI

by bigskyTi

Here is another great write up originally from someone on this site that resurfaced over on BF.

Apologies to the original author as this is an unidentified cross-cross post

"I concur with the last person who posted a comment about the softness of the Testors enamel paint. In that it may look fine to photograph a bike that sits indoors, it can never stand up to abrasion or weather, not to mention a good past wax. I am not satisfied if a touch-up can be detected from 6 inches away, much less 6 feet.

I first prep the chip by deciding if there is rust in the pit or not. Also if there is loose or chipped paint I will remove it with a small needle file. With a toothpick I will dab a drop of Naval Jelly just big enough to fill the chip hole. It is important not to let the Naval Jelly to run on the rest of the painted frame. I fill several chip holes at the same time and wait at least half an hour and then wipe the area(s) off with a wet rag. If you became friends with an auto body shop, you could secure a small bottle of epoxy primer and catalyst. I was fortunate enough to find a can of each at a yard sale...enough for 30 years of filling in scrapes and stone chips. I will mix the catalyst and the resin a couple of drops at a time on the lid of a paint can and again apply the primer with a clean toothpick. Wait about a half hour for it to dry.

The paint products I prefer are from the automotive paint company "Dupli-Color" Although they don't have every color under the sun, their products are LACQUER and the lacquer works better, dries faster, shapes, sands, and polishes better than anything else I have found. I always have a bit of lacquer thinner on hand when I work the touch ups. If the chips are excessively wide or very deep, you must also make the determination of using a 'spot putty', also available at auto supply houses. This stuff is thick and goes over a primer then should be primered AFTER it is sanded smooth.


I fill a small metal cup with the lacquer and slightly thin it, filling up an artists brush till its full. We are not just painting to cover the chip but filling the void. So I give a slight push to the brush and draw it out slowly watching for the 'dome' to show on the filled hole. Lacquer can dry in as little as 10 minutes so there is a chance to do several chips in a single pass. One of the methods I use to level the new paint is to have those flat wooden swizzle strips that better coffee shops have on hand. I usually make about a dozen disappear on a visit. When I get home, I will sand the ends smooth and then super glue 320, 400, and 600 grit strips to the ends. This is what takes off the rounded dome of the chip. If the paint is not 'proud' you will have to do it again. Successive sanding is followed by using the nail buffers that your wife has. If you are certain of your masculinity, you can go to a beauticians supply and pick ups a small pile. The grit of these abrasives are not specified, but will be down to about 1000 grit if you chose right. One one side there is usually a 'buffing' or polishing side without abrasive. This is the final step. Buff out any of the course grit marks and then stand back and admire the work. You then may apply a thin coat of clear if you wish. I just finished a GRANDIS that looked like it was rolled down a cliff and is now almost show-room quality. You can't tell where the chips were from 3 inches."

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musanoadsaba
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Location: Canadian Rockies

by musanoadsaba

So what is the proper grit progression used for a job similar to the Bontrager stem above?
mur

pharding
Posts: 335
Joined: Wed Jan 07, 2009 1:50 am
Location: Chicago

by pharding

Hey! At least give me credit, I cross posted it fair and square.
bigskyTi wrote:Here is another great write up originally from someone on this site that resurfaced over on BF.

Apologies to the original author as this is an unidentified cross-cross post

"I concur with the last person who posted a comment about the softness of the Testors enamel paint. In that it may look fine to photograph a bike that sits indoors, it can never stand up to abrasion or weather, not to mention a good past wax. I am not satisfied if a touch-up can be detected from 6 inches away, much less 6 feet.

I first prep the chip by deciding if there is rust in the pit or not. Also if there is loose or chipped paint I will remove it with a small needle file. With a toothpick I will dab a drop of Naval Jelly just big enough to fill the chip hole. It is important not to let the Naval Jelly to run on the rest of the painted frame. I fill several chip holes at the same time and wait at least half an hour and then wipe the area(s) off with a wet rag. If you became friends with an auto body shop, you could secure a small bottle of epoxy primer and catalyst. I was fortunate enough to find a can of each at a yard sale...enough for 30 years of filling in scrapes and stone chips. I will mix the catalyst and the resin a couple of drops at a time on the lid of a paint can and again apply the primer with a clean toothpick. Wait about a half hour for it to dry.

The paint products I prefer are from the automotive paint company "Dupli-Color" Although they don't have every color under the sun, their products are LACQUER and the lacquer works better, dries faster, shapes, sands, and polishes better than anything else I have found. I always have a bit of lacquer thinner on hand when I work the touch ups. If the chips are excessively wide or very deep, you must also make the determination of using a 'spot putty', also available at auto supply houses. This stuff is thick and goes over a primer then should be primered AFTER it is sanded smooth.


I fill a small metal cup with the lacquer and slightly thin it, filling up an artists brush till its full. We are not just painting to cover the chip but filling the void. So I give a slight push to the brush and draw it out slowly watching for the 'dome' to show on the filled hole. Lacquer can dry in as little as 10 minutes so there is a chance to do several chips in a single pass. One of the methods I use to level the new paint is to have those flat wooden swizzle strips that better coffee shops have on hand. I usually make about a dozen disappear on a visit. When I get home, I will sand the ends smooth and then super glue 320, 400, and 600 grit strips to the ends. This is what takes off the rounded dome of the chip. If the paint is not 'proud' you will have to do it again. Successive sanding is followed by using the nail buffers that your wife has. If you are certain of your masculinity, you can go to a beauticians supply and pick ups a small pile. The grit of these abrasives are not specified, but will be down to about 1000 grit if you chose right. One one side there is usually a 'buffing' or polishing side without abrasive. This is the final step. Buff out any of the course grit marks and then stand back and admire the work. You then may apply a thin coat of clear if you wish. I just finished a GRANDIS that looked like it was rolled down a cliff and is now almost show-room quality. You can't tell where the chips were from 3 inches."
Last edited by pharding on Sun Sep 20, 2009 11:05 pm, edited 1 time in total.

Dybersh
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Joined: Wed Jan 28, 2009 5:09 pm

by Dybersh

Cool saddle! ;)
It's all about the weight!

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angoose
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Joined: Thu Nov 06, 2008 12:17 pm

by angoose

Is it possible to sand off only a small area of paint (say you only wanted to get rid of the xxx in the stem above but leave the rest of the decals) rather than the whole clearcoat and then redo the clearcoat on that spot and have it match up with the original coating?

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Frankie - B
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by Frankie - B

@musanoadsaba & angoose

I'll try to come back to your questions asap.
'Tape was made to wrap your GF's gifts, NOT hold a freakin tire on.'

whodesigns
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by whodesigns

angoose wrote:Is it possible to sand off only a small area of paint (say you only wanted to get rid of the xxx in the stem above but leave the rest of the decals) rather than the whole clearcoat and then redo the clearcoat on that spot and have it match up with the original coating?


You could sand a local area to remove a decal and leave other decals in place. I would give the whole item a fresh coat of clear instead of trying to blend it in. You just need to prep it well, light sand and degrease the entire stem.
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thesmokingman
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Joined: Mon Dec 29, 2008 11:18 pm

by thesmokingman

musanoadsaba wrote:So what is the proper grit progression used for a job similar to the Bontrager stem above?


I just fixed up an old carbon mtb bike recently. The whole thing was pretty knackered up. I started w/ 400/800/1500 grit and finished it off with a cutter/polisher combo, System One. The cutter/polisher really brings out the shine, especially if you have to deal with dust or lint on your clear coat. Zap it with 1500/2000 paper, then use the cutter/polish combo. The clear that I used is a pretty good UV blocker, U-Pol #1.

Here are some pics:

BEFORE
Image
AFTER
Image

BEFORE
Image
AFTER
Image

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syce
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by syce

soloist carbon

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Frankie - B
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by Frankie - B

For the stem above, I didn't use any grit progression. I just started with the smallest grit of wet sandpaper I could find.

Going to finer grits would probably have given a smoother result...
'Tape was made to wrap your GF's gifts, NOT hold a freakin tire on.'

by Weenie


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