Proper sanding steps?

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Sanjuro
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by Sanjuro

Crash put some scratches in the clear coat down to the carbon on the bottom tip of one of my Record shifters. Can I use the blade method to scrape the area smooth once again and re-clearcoat?

by Weenie


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gumgardner
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by gumgardner

Yah I think so. I used a sander on a dremel and it left some nicks and gouges. I went back over it with a sharp balde and smoothed out the nicks.

As for the orbea, I don't see why it would be impossible. It'll take a bunch of razors. I got a box of 10. Cost $2.50. Lol. It's so easy. Just press hard when you scrape and big 'strings' of white coating come off. Then as you get closer to the carbon it becomes grey and then black when you hit the carbon. I press hard until I see grey and then I use light pressure until I get black and then very fine pressure to fix and imperfections at the carbon level.

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bobsled
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by bobsled

Mr.Hyde wrote:Trust me, I'm an engineer (or at least trying to become one :lol: ).


Edit: Concerning Shifters: http://lcblog.lotz-carbon.de/index.php? ... basteleien" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; , also done with blades, like the WCS fork here: http://lcblog.lotz-carbon.de/index.php? ... basteleien" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;.
I also have cleaned a frame and a bar, all works out fine, just the areas where some tubes come together isn't that good, you'll have to sand there in most cases.


Very nice work. I really like the shifters. So what method did you use (blade or sand paper)?

I decided to strip a SRAM Force crankset to raw carbon and leave it that way. I've used the razor blade method and I'm almost done w/ the NDS crank arm. I was able to remove about 90% of the clear coat and paint. I want to finsih it off using wet sand paper and then protect w/ Aerospace 303 protectant. So my question is, if I've already removed the clear coat and paint with a blade what grit wet sand paper would folks recommend to finish it off?

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Last edited by bobsled on Wed Dec 07, 2011 6:59 pm, edited 1 time in total.

voodoojar
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by voodoojar

You need to finish wit ha much finer grit IMO like all the way up to 2500-3000 This is going to make the gloss way more smooth.
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bobsled
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by bobsled

Thanks. Did you spray clearcoat on that?

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Fourthbook
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by Fourthbook

I'm very interested in this thread as I intend to remove the decals on a Campy SR crankset to expose the wonderful UD finish. Sounds like the razor blade technique is better than sanding or chemicals (Carbo-Lift or acetone), with perhaps a bit of finish sanding to smooth out any nicks in the surface before waxing. Any further advice/experiences would be appreciated!
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bobsled
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by bobsled

^ ^ I would think the only safe chemical option would be Carbo-lift. Anything else could cause damage to the carbon's resin.

CrazyErrol
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by CrazyErrol

The razor tip is sweet. I just took the decals off some Force cranks I have for my forthcoming gloss carbon c59, the rest of the build is Di2 but I'm not keen on the shimano cranks.

Took me about 5 minutes!

I used a good quality, small kitchen knife and sharpened the hell out of it, kept sharpening it while working, about 2-3 times. Having the handle on the knife, and it being small (2-3 inch blade) meant I could use Gum's back n forth technique very quickly and safely. This was good to take the last dregs of the decals off and not go too deep into the remaining clearcoat. I got the bulk off initially with fairly pressurised, long drags of the blade.

I'm left with a smooth surface with is dulled from the process, if I wet it, it looks perfect so think I could either buff and polish the remaining clearcoat of just give them a quick blast of clear.

Interested too to hear how the above finish on the forks was acheived.

If it's easy enough I am gonna be sorely tempted to take some of the stupid logos off my C59 when it turns up. CHS-revolution, I'm looking at you! :lol:

I hear the logos are painted on, but surely they will be onto a layer of clearcoat rather than straight on the carbon. Any ideas anyone?

This is the frame I'm awaiting...I could quite happily lose the top tube (CHS) logo, maybe seat tube too.

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Mr.Hyde
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by Mr.Hyde

bobsled wrote:^ ^ I would think the only safe chemical option would be Carbo-lift. Anything else could cause damage to the carbon's resin.


I heard that Carbo-lift also might not be that harmless, on the other hand epoxy has good resistance against most chemicals, so there might be other chemical solutions that might work. However - two-components-coat is hard to get off chemically, I'd absolutely suggest the cutter knife.

CrazyErrol
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by CrazyErrol

gumgardner wrote:Kitchen knife?! Wow. Next time, try one of these... http://www.popularmechanics.com/cm/popularmechanics/images/2S/razor-blades-470b-0908.jpg


Sure, a blade's a blade. It does the same job just needs to be super sharp like a chisel. The moment I felt the effort needed changing, I sharpened it. Also I have a lot more control than using a razor held in my fingers. I did some bottle cages today too, actually the convex blade was really handy with the wavy shape.

I restore houses for a living in London and work on sash windows and that sort of thing. I have a collection of tools that I can only describe as being like a 90 degree chisel blade. A very precise shaving tool for use on old paints and wood. I think the smaller ones if kept carpenter sharp would be perfect here. The level of control and leverage is a world away from a razor blade. I have them in various shapes and sizes but only ones I can find online are like in this link. I reckon they'd go through a fork or tube in no time.

http://www.allwaytools.com/List.asp?Mat ... RS&Level=5

Hehe I wanna buy some battered old c40 now just to strip the thing.

voodoojar
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by voodoojar

That knife work in the photos looks like crap. There are all sorts sorts of scars in the carbon. I understand being lazy but the craftsmanship is awful. I dont know why you'd want to ruin or risk ruining expensive parts like that. It might take 5x as long with sandpaper starting from 400 and work your way up to 3000 but it's worth it when the part turns out perfect.

gumgardner
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by gumgardner

No scars in my work :wink:

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bobsled
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by bobsled

voodoojar wrote:That knife work in the photos looks like crap. There are all sorts sorts of scars in the carbon. I understand being lazy but the craftsmanship is awful. I dont know why you'd want to ruin or risk ruining expensive parts like that. It might take 5x as long with sandpaper starting from 400 and work your way up to 3000 but it's worth it when the part turns out perfect.


I assume you're talking to me, I didn't use a knife, I used razor blades like the ones in gum's link. Also, I'm not finished! Up near the BB I hadn't even started. It's a crappy cell phone pic so lighting plays funny things. No "scars" besides, I plan to finish it off with at least two passes on wet sanding. All I asked was for some help from the experts.

by Weenie


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gumgardner
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by gumgardner

Keep in mind also, the lay ups for these carbon components are not aways pretty...hence the thick clear coat and dyed carbon fibers. You can see on my Edge 1.0 fork some pretty noticeable seams, which I'm fine with, but didn't pop up until I removed the outer clear coat.

No need to sand either. Just use a new sharp razor and do finer/lighter strokes. It shines up really nice. I don't sand anything. Initial strokes are pretty hard to engage the clear coat. It should come off in sheets. You'll know you are still on the clear coat bc the the component has a whitish appearance and white piece flake off. Once it becomes dark you know you hit carbon. At this point you should be finishing up and the strokes should be VERY light. No sanding is needed.

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