scoobyis2cool
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| posted on 14/9/04 at 11:47 PM |
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Carbon fibre vs fibreglass
What are the advantages/disadvantages of carbon fibre as opposed to fibreglass for body panels? How much more expensive is it? Is it easy to use? Has
anyone on here attempted to use it for their project?
Cheers
Pete
It's not that I'm lazy, it's that I just don't care...
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pbura
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| posted on 15/9/04 at 12:50 AM |
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Try a search on 'carbon' for user 'Syd Bridge' and you'll get the better threads.
Cool stuff if you can afford it!
Pete
Pete
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stressy
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| posted on 15/9/04 at 06:43 AM |
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Mainly carbon fibre on non-race vehicles is about the look i would say.
As a comparison of typical wet lay materials as this is what you are likely to use, assume a 1m square panel 1mm thick.
woven carbon / epoxy weight approx1.7kg
Woven E-glass / epoxy weight approx 2kg
The elastic modulas (stiffness parameter) of the carbon will be around that of aluminium but the E-glass will be around 1/3rd of that.
Clearly if you are making a bonnet for example then carbon will provide sufficient stiffness for less weight. For lowly loaded parts you will often
find that due to materials avaliable you cannot get the laminate down to the required thickness and it ends up being over heavy and hence closer to
the weight of the glass part but at considerable extra expense.
Carbon is not as damage tolerant as glass, where glass may bend and eventually crack, carbon will at its limit explode. The inherrent failue mode of
the material which fails under high load but low deflection (due to bending for example)
Cost wise assuming woven fabric and the same resin in each case the carbon fabric will probably cost in the order of maybe 6 times the price of the
glass, soyou can esily weight up the options.
In my opinion carbon is good where deformation of panles is critical, not often the case for a locost. As such i would look at going with glass and
maybe experiment with stiffening using either unidirectional tape or closed cell foam cores.
My apologies for the rambling nature of this post but it is rather early
Happy laminating
Cheers
Chris
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Hugh Paterson
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| posted on 15/9/04 at 08:02 AM |
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Also if you intend making a feature of the carbon cloth, visable through your gelcoat surface its a twat getting all the air out of it unless you play
with it a lot, nothing worse than lots of £££ spent on the fabric when you have a panel that has more bubbles in it than an Aero choclate bar.
Shug.
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Cita
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| posted on 15/9/04 at 05:12 PM |
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Carbon is also very good in slicing your body when shatered in a crash!!!
The carbon particles are razor sharp!
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derf
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| posted on 15/9/04 at 08:25 PM |
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I use Carbon Fiber in my RC car, I switched from aluminum. I used to use aluminum that was 5x as thick and 10x as heavy, and I would bend shock towers
and other high stress parts on a regular basis. Then I discovered a company that makes CF shock towers, Ive broken a few, but not quite as many. and
yes when they break they really break, but they are stronger than aluminum.
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Lightning
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| posted on 15/9/04 at 09:25 PM |
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A guy I know is making a body all in carbon fibre for a Tiger 6 . Looks good too.
Easiest way to loose weight is to go on a diet!
I have carbon dash and had to be very careful with ignition wires.
[Edited on 15/9/04 by Lightning]
Steve
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scoobyis2cool
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| posted on 16/9/04 at 01:11 AM |
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Thanks for all the replies, the reason I was asking wasn't so much from a weight saving point of view, it was more to do with the fact that I
know a lot of supercars use carbon fibre and wondered if it had some major advantage over fibreglass that would justify its price.
I'm looking into the possibility of designing and building a car from scratch and was considering using to make a one piece body
Pete
It's not that I'm lazy, it's that I just don't care...
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pbura
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| posted on 16/9/04 at 12:20 PM |
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Carbon fiber supply is monopolized, along with being all the rage, causing the high prices.
I read about a car with a monocoque chassis made of divinycell, CF, Kevlar, and S-glass. Looked at some prices for materials and estimated a cost of
about $70 per square foot, and this may have been low. Would be very light and strong, but...
You could always hang onto your molds and use fancy materials some other day. Alan B. has talked about doing this. 
Pete
Pete
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