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PostPosted: Wed Dec 21, 2011 5:32 pm 
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CarlTroy wrote:
I would love to be able to put my frame in the oven when finished with the sanding :)
I guess current ovens are simply not up to the task


For my small parts I use the home oven but I work for a company that makes equipment for the food industry and we have industrial sized ovens at work so I could do your frame for you if you like. :wink:

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Posted: Wed Dec 21, 2011 5:32 pm 


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PostPosted: Wed Dec 21, 2011 6:43 pm 
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Location: Escondido, CA
Mr.Hyde wrote:
Genshammer wrote:
If you are going to sand your frame to the bare carbon, you really need to put some kind of UV protectant on the entire frame. Whether it's an automotive grade clearcoat or otherwise, if you don't UV protect it, over time the sunlight will begin to degrade the resin system, weakening the structural integrity of the frame.


:lol:

You don't need UV protection on CF-EP-laminates. The fibres are intransparent for UV light, so the matrix won't geht any damange below the first fibre. You might get some yellowing on the outside of your part, but there is no significant loss in structural integrity :wink:

That might be different for GF or AF, because laminates made from these fibres are transparent or translucent.


One of just many pieces of evidence supporting my statement that exposed carbon fiber can degrade when exposed to UV light and moisture:

http://me.eng.sunysb.edu/~compmech/downloads/N29.pdf

:lol:

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PostPosted: Wed Dec 21, 2011 10:02 pm 
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Genshammer wrote:
Mr.Hyde wrote:
Genshammer wrote:
If you are going to sand your frame to the bare carbon, you really need to put some kind of UV protectant on the entire frame. Whether it's an automotive grade clearcoat or otherwise, if you don't UV protect it, over time the sunlight will begin to degrade the resin system, weakening the structural integrity of the frame.


:lol:

You don't need UV protection on CF-EP-laminates. The fibres are intransparent for UV light, so the matrix won't geht any damange below the first fibre. You might get some yellowing on the outside of your part, but there is no significant loss in structural integrity :wink:

That might be different for GF or AF, because laminates made from these fibres are transparent or translucent.


One of just many pieces of evidence supporting my statement that exposed carbon fiber can degrade when exposed to UV light and moisture:

http://me.eng.sunysb.edu/~compmech/downloads/N29.pdf" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

:lol:


Have you read the paper? The specimens only exposed to UV lose just a very little percentage of stiffness and strength. And, in fact, the positive effects of moisture at least compensate the negative effects of UV radiation. In addition the wall thickness is relatively low (but something usual for bicycle components), the negative effects will be the lower, the thicker the specimen is (like I said, the UV radiation just gets to the first fibre - behind the fibre there is just darkness :lol: ).
For me this paper points out, that it is not necessary to put on some coating on CF-EP parts, because the losses in E|| and R+|- are less than in most cases for examle numerical mistakes are. In addition E|- will decrease more than E||, so the effect of the decreasing R+|- is also at least partly compensated through redistrubution of stresses within the different layers.

Or, otherwise said, if the bike part has that low safety factors, that the very small effect of UV radiation comes to an effect, you should not ride it...

Concerning the influences of moisture, they are mostly positve, (break strain under Sigma|- + for example), so negative effects of moisture are overcompensated by positive effects in general. See http://books.google.de/books?id=GVN_V1o ... &q&f=false fore more information. That's one of the standard books in the countrys where german is spoken, it's written by my professor, who was postgraduate with Puck and developed the newer version of the Puck criteria of failure together with Puck. You will hardly find someone who knows more about those things then he does :) .

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PostPosted: Thu Dec 22, 2011 1:05 am 
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Mr. Hyde, you confused me but I enjoyed it :mrgreen:

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PostPosted: Thu Dec 22, 2011 5:37 pm 
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Even the slightest indication that degradation could be a factor is enough for us to recommend clearcoating all carbon fiber. Since we operate a business, we have to err on the side of safety - that is our #1 priority for all customers. What one does in his garage with his own frame is up to him, but if we are to repair a frame, we have to recommend clearcoating, regardless of how minimal the degradation can be.

But I won't tangle with you Mr. Hyde, it seems you know your stuff, and I never claim to be very smart!

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PostPosted: Fri Dec 23, 2011 12:03 am 
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I don't claim that either :D . Sure it's nice to protect a part, but if you have a look at AX Lightness, Lighweight by Carbonsports, various carbon rims, Schmolke, MCFK, space-stuff and car racing parts, many of that parts do not have any clear coat, although they see UV radiation within their product life.

I also do some engineering for for various producers of lightweight stuff, I never instruct them to use UV protection for technical reasons. Of course I never made that examinations that for example the guys from NYC in the paper you posteted made. But science (also the paper you posted) and experience show, that for CF-EP a coating is not necessary. It's helpful to prevent the parts from yellowing, and it's mandatory for AF-parts and maybe GF-parts, and in general a coated part has a better finish than a raw part. That's it.


Edit: Of course you are absolutely right trying to be on the safe side - there are enough manufacturers without enough know-how, allways being on the unsafe side. That's the worst you can do, it's infinitely better to prevent parts even from not-so-important enviromental influences. :beerchug:

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PostPosted: Mon Jan 23, 2012 10:06 pm 
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This is my stripped saddle - still needs a little bit of work but nearly there. The before shot is on page 4. Most of the work was done by a water based solvent free paint stripped which I guess must be a similar product to carbolift? This removed all of the paint and some of the clear lacquer. The remaining laquer was then very soft and easy to sand off. When wet the marbled finish to the carbon looks fantastic so that's what I'm guessing it'll look like when I'm finished.

I'm not sure what to finish it with though? A clear spray from a model or auto shop? Does any one have any pics of components re-finished with the aerospace 303 stuff?

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PostPosted: Mon Jan 23, 2012 10:20 pm 
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How it looks when wet
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PostPosted: Mon Jan 23, 2012 10:43 pm 
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I've been stripping a Cervelo branded 3T Funda. I found the blade method worked really well on the outside of the fork legs, but the inner sides really need 600 grit to remove the paint. Looks good so far though.

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PostPosted: Tue Jan 24, 2012 9:57 pm 
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Clear coated today. Pretty happy with it though I've got a patch of overspray right in the middle which dried, but you'd only notice that close up so overall definitely worth doing.
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PostPosted: Tue Jan 24, 2012 11:16 pm 
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Location: Sydney, Australia
Not sure if anyone is interested but i debadged a zipp sl bar last night using the following steps:

Using one of those foam sanding blocks you can buy from art stores, i took the top coat off and brought it almost down to carbon. The foam block is good because it conforms to and shape of the bar and gives a more even finish. It was a medium strength one but there are heavier duty ones if you want to do it faster.
Image
I hit any spots that still had some clear with some 600 paper wrapped around the foam block and gently took it down to the carbon.

I then went through 800,1000,1200, then 1200 wet until the finish was really smooth.

Because it wasn't really hot enough for me to paint i applied a finishing wax to the carbon which gave it a beautiful satin finish. when i get a better camera ill take some better photos to show this. the wax can be easily reapplied or even removed if i decide to gloss paint it.

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PostPosted: Mon Aug 27, 2012 6:28 pm 
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gumgardner wrote:
I used a razor blade to remove the clear coat and decals from my 2011 Super Record 11sp Group and Edge 1.0 fork. Savings...11g :beerchug:

Image

I still need to remove the coating off of the derailleur plate.

Pretty impressive... especially the fact, that you have been able to get into all the teeny weeny corners with a razor blade.

I am going to remove the decals on my Look bottle cages - and still considering whether to sand or "raze" them.

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What would you recommend?

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PostPosted: Mon Aug 27, 2012 6:32 pm 
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jsinclair wrote:
Because it wasn't really hot enough for me to paint i applied a finishing wax to the carbon which gave it a beautiful satin finish...


What kind of wax did you use?

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PostPosted: Tue Aug 28, 2012 1:06 pm 
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I am razoring and sanding an evo frame currently. Frame 75% done. Fork complete - razor then 1200 grit works perfectly. Also done my red RD and shifters. Ritchey seatpost and stem next, and tops of 3T ergonova LTD bars. Will post completed pics.

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PostPosted: Tue Aug 28, 2012 2:37 pm 
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The razor and sanding part I have nailed but how are you doing the clear coat so that it is like original. I have used some very high end clear coat on my own but it never seems as good as having a professional do this. I am thinking about doing my SRAM RED lever and some other parts but I want the clear coat to be perfect.

I even set up a small little spray booth out of a larger cardboard box with a hole in the top so that I can hang wire down the middle to spin the item being sprayed.

What I have done in the past is do a light clear coat, bake it in the oven for 45 on 180f then wet sand and repeat 3 times in total with the final baking for 1 hour at 180f.

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Posted: Tue Aug 28, 2012 2:37 pm 


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