Moorron
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 posted on 23/8/06 at 09:46 AM |
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finish of carbon fibre?
This is not a complaint to the company I bought it from, but might be if people here in the know say it should b.
I finally received my 1000mm x 1000mm x 1mm prepreg yesterday. But the pattern of the weaves isnt very nice looking. Im using this stuff to cover the
tunnel and boot of my indy. But its now going to look pants as I wont b able to line up the weaves around the boot bits.
I will post a pic tonight, but to describe how it looks is like an open curtain, its got 'folds' in 30% or more of the surface area (not
all in one area too), its hard to explain, but its got a ripple effect over it. The panel is flat and smooth, its just how the light is reflecting off
the weaves that make it look so odd.
Is this normal for flat prepreg? Someone here at work who has delt with this stuff before says it hasn’t cured correctly and I should send it back.
But as I honestly don’t know if this is right or just the typical finish of carbon fibre sheet I don’t wont to reject it for no reason.
Ps, never picked up CF before and wow is it light and rigid.
Sorry about my spelling, im an engineer and only work in numbers.
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smart51
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| posted on 23/8/06 at 09:48 AM |
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Do you mean prepreg or is it a fully cured panel? Prepreg is flexible and has to go in an oven to be cured.
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Moorron
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| posted on 23/8/06 at 09:53 AM |
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erm... its advertised as prepreg on the website, but its hard as nails. which is what i wanted. just the finish isnt too nice.
Sorry about my spelling, im an engineer and only work in numbers.
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skydivepaul
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| posted on 23/8/06 at 09:56 AM |
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depends on the pre preg carbon that has been used. some of the aerospace stuff has fantastic rigidity (they make the wings out of it) but it looks
pants. just has lines running in one direction, this stuff is functional and doesnt have to look pretty 'cos no one sees it.
The stuff you would expect to fit on an exposed panel on a car etc should still have the strength and rigidity but will have a 2x2 weave. this stuff
looks much nicer and will also have a nice gloss finish.
depends what you have ordered?
http://www.smartideasuk.com
http://www.smartmapping.co.uk
HD CCTV
3D design solutions and integration
IP security systems
access control systems
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Moorron
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| posted on 23/8/06 at 10:07 AM |
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i was told by the company his supplier does F1 stuff so i suppose looks arnt that important. But this is 2x2 weave.
i think a pic is best as u can advise better, but i will have to do this when i get in this evening.
i will use it if its supposed to be like this, alltho its not as expected. but i would prefer the pattern to b uniform.
Sorry about my spelling, im an engineer and only work in numbers.
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skydivepaul
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| posted on 23/8/06 at 10:25 AM |
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post up a picture when you get the chance. a professional cabon fibre sheet should be light, straight, strong and also have a nice gloss finish. How
much did you pay for it? that will also reflect the quality of the product.
http://www.smartideasuk.com
http://www.smartmapping.co.uk
HD CCTV
3D design solutions and integration
IP security systems
access control systems
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Syd Bridge
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| posted on 23/8/06 at 12:05 PM |
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The only carbon weave that is easily used is the plain weave, and this usually has a fairly 'hard' finish dry. It is usually consistent
when going to prepreg.
The twills and satins are meant to be 'drapeable' in complex shapes, so by their nature are fairly open and flexible. Very difficult to
keep the fibres straight in any context.
As an example, I made a test sample for strength evaluation, and four layers of 280gsm carbon still had enough gaps between the weave, that when held
up to the light, it appeared to have pinholes through it. The 'holes' were filled with resin in the layup, but still translucent.
So, this is what you are fighting against.
If you want a good appearance, the layup needs great care, and backing with a black impregnated resin.
Cheers,
Syd. 
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Delinquent
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| posted on 23/8/06 at 12:32 PM |
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Syd, have you ever tried using a very light spray of 3M adhesive before layup with the twill? Gives it a very small amount of hold while you are
manueovering it to stop it coming apart quite so much. (and also stops the dreaded de-matting of the edges!)
TBH the few times I've bought finished sheets rather than making up myself I've been quick to complain on poor quality finish and usually
get replacement no problem!
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pawgrp
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| posted on 23/8/06 at 01:39 PM |
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Hi
The weave pattern on your sheet may have become distorted when the cloth was laid out. If it was an epoxy impregnated cf cloth then the weave will not
be as inclined to move compared to a dry cloth. It would be interesting to know if it is genuine pre-preg or just a polyester resin and cf cloth
layup.
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02GF74
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| posted on 23/8/06 at 02:52 PM |
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paint it wit hhammerite and stop whingeing
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Moorron
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| posted on 23/8/06 at 07:13 PM |
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http://www.locostbuilders.co.uk/upload/DSC00752.JPG
Sorry about my spelling, im an engineer and only work in numbers.
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Moorron
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| posted on 23/8/06 at 07:14 PM |
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well what u think? not too pretty. do i have the authority to reject it?
[Edited on 23/8/06 by Moorron]
Sorry about my spelling, im an engineer and only work in numbers.
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Delinquent
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| posted on 23/8/06 at 07:25 PM |
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personally I'd reject it, I only pay for things done to a quality I would expect from my own workmanship!
Are those ripples raised at all, or are they purely in the weave pattern? either way I'd reject it, but in the past I have had a piece like
that, that was not only horrid to look at, it wasn't flat! they hadn't placed the vacuum bag properly and it had rucked when switched on.
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Moorron
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| posted on 23/8/06 at 07:49 PM |
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no its flat and only 'looks' like that. cost me £200.
Sorry about my spelling, im an engineer and only work in numbers.
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Delinquent
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| posted on 23/8/06 at 08:07 PM |
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well, it's up to you at the end of the day, but I wouldn't accept it, especially if it's going to be seen!
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JoelP
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| posted on 23/8/06 at 08:28 PM |
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ring them and politely say that the piece you wanted needs to be aesthetically pleasing, not just functional. Ask them to swap for a piece with a
better appearance. Entirely reasonable IMHO. Im not sure why they would sell it looking like that to be honest, as nearly all carbon they sell will be
for people who want something to look bling.
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LEGACYTURBS
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| posted on 23/8/06 at 08:45 PM |
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Very poor finish, I would'nt pay for that. If you get stuck and want some propper stuff, I have really mint large sheets of carbon in stock 
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nick205
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| posted on 24/8/06 at 08:17 AM |
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IMO that's not acceptable and should be returned for a replacement or full refund if that's the best they can do.
I had a similar experience recently (different supplier mind) with a CF dashboard where the weave wasn't so bad, but the actual surface was
badly pitted with air bubbles and other blemishes. I was not going to spoil the work I've already done on my car by fitting something that
lloked crap - a refund was a sought and given.
You know if you fit it you'll always be unhappy with it 
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Syd Bridge
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| posted on 24/8/06 at 08:53 AM |
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Mooron,
From the picture, it's either pulled threads, or 'wavy' layup.
When you look at the back, rough, side; is it flat, or thicker where the wobbles are? If it's thicker, then it's a quick and particularly
nasty wet layup. If it's flat both sides, then it's just pulled threads. Not pleasing aesthetically, and not very useable from a strength
point either.
Cheers,
Syd.
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Moorron
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| posted on 24/8/06 at 12:09 PM |
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Thanks guys, after showing a pic to a work mate whos used CF before, he said sent it back so i have emailed the company and awaiting a responce. I got
no excuse now to get out of the bathroom tiling this w/e.
Syd, its flat both sides, evenly thick and about as glossy on the back as the front (semi).
I will update when i get the responce.
Cheers.
Sorry about my spelling, im an engineer and only work in numbers.
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Moorron
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| posted on 13/9/06 at 02:53 PM |
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Just to update on this, said company sent a new sheet to me within 10 days of me sending the old one back. They suggested i originally ordered the
wrong type and wetlay is what i really wanted as its more for cosmetic purposes, cheaper and have larger sheets available (which is good as i wanted a
sheet to also do my dash). It arrived and looks fantastic and i will start to work on it soon.
Result.
Sorry about my spelling, im an engineer and only work in numbers.
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