mranlet
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| posted on 31/7/03 at 09:18 PM |
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Carbon Fiber Cloth
Carbon Fiber Cloth - Would it work for a Locost-style car? My car isn't truly a "Low-Cost" but Carbon Fiber cloth can be found on
the internet very inexpensively. I am very interested in using it but my trouble is that I don't know a whole lot about it...
I know that you are supposed to coat it with a resin to give it its rigidity, but what kind of resin?
I'm sure that it would work for things like body panels and wings, but would it be able to be used to re-enforce the transmission tunnel or
firewall? How could it be joined to the steel frame? Maybe in replacement of a steel frame? Does anybody know?
Thanks!
-MR
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robinbastd
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| posted on 31/7/03 at 09:32 PM |
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Do a google search for CFS, they stock it and are a helpful bunch. I was shown around their warehouse and the guy was really helpful. AFAIR you need
epoxy resin when using cf,and a wet lay up will never be anywhere near as strong as the vacuumed/autoclaved stuff. For strong decorative cf panels
you'll need a big sheet of glass or formica to lay the cloth onto a layer of epoxy. Bought a good book on the subject which a mate borrowed
immediately.............must get it back. Hope this helps
Ian
Just realised that you're in the states,so CFS aint exactly local............
[Edited on 31/7/03 by robinbastd]
Only a dead fish swims with the tide.
http://smuttygifts.com/
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mranlet
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| posted on 1/8/03 at 02:51 PM |
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You say that even the poly-based stuff will work for re-enforcing the transmission tunnel?
I talked to the president of an R/C airplane orginazation yesterday who knew a little about the subject. I learned that:
-Carbon fiber is only strong in tension and is much weaker in compression
-Carbon is not nescessarily light (think of a lump of anthricite coal or a canister of graphite librucant) but it is strong so you can use less of
it
-In order to be shaped it requires a mold just like fiberglass
-Multiple layers of carbon fiber can be bonded together with honneycomb mesh that can be attached with an epoxy resin
-The further away the layers of carbon are, the stronger the panel
I still don't know what electrolysis is, how vaccumn bagging would work on carbon fiber, or how to attach carbon to a metal frame. My idea was
to envelop the frame members in carbon while being aware that there will be no adhesion between the metal surfaces and carbon surfaces (i.e. wraping
the cloth in 2 or 3 dimensions). If the best way to attach the carbon is to rivet it heavily, I may as well just use steel plate.
I plan to use carbon fiber for the body panels and impact-foam-filled side pods, budget permitting, but I'm still unsure if it will be possible
to use it for structural re-enforcement. Anyone's help would be greatly appreciated!
Thanks for the input!
-MR
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Peteff
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| posted on 1/8/03 at 06:20 PM |
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Structural carbon fibre is produced by an entirely different process to decorative carbon fibre which is what you are looking at if you use the resins
that are more commonly used with glassfibre. It is very expensive to produce as it uses a baking process and is thus mostly used for costly parts for
out and out racing, not a road car. Read up about it before you think about using it in any structural capacity.
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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mranlet
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| posted on 4/8/03 at 01:07 AM |
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What kind of temperatures are we talking about for baking?
I recently learned that "carbon fiber is twice the strength of steel at half the weight of aluminum" meaning that at the same strength of
steel it would be 15% of the weight
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D Beddows
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| posted on 4/8/03 at 10:23 PM |
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I would definitely say no to using it for reinforcing anything - the little I know about carbon fibre composites says that the strength of the
finished article depends on the orientation of the fibres in a multiple layup (which can be adjusted to give strength in different directions for
different applications if you know what you're doing) but then you realy need to vaccum pack and cook it in an autoclave to give the finished
component any kind of structural integrety.
Most of the 'carbon fibre' stuff you see for sale is 90% cosmetic (I would imagine it's quite hard to break completely as cutting
proper carbon fibre mat with conventional tools is nigh on impossible) but producing safe structural items in carbon fibre at home isn't ever
going to work unless you have THE most amazing garage/workshop
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mranlet
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| posted on 7/8/03 at 05:37 PM |
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My garage isn't that amazing, but I did have multiples of all the tools that Ron depicts in his book...
...and my dad and I build our own painting booth in our basement in Connecticut complete with external ventelation...
...and I do have access to a professional garage with lifts, air tools, diagnostic computers, wheel balance machines, timing systems, anything a
mechanic could want...
...and I have access to a painters oven, used at temperatures in the vicinity of 50-250C to bake on paints...
...and I know someone who operates a hydra-cutter (a water jet shot at mach 5 can cut anything)...
What kind of a process are we talking about for making carfon fiber rigid? I could probably find a way to do it.
Thanks
-MR
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timf
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| posted on 8/8/03 at 02:55 PM |
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quote:
Originally posted by mranlet
...and I have access to a painters oven, used at temperatures in the vicinity of 50-250C to bake on paints...
Thanks
-MR
an autoclave runs from between 150 up to 500 degrees ant pressures of about 150 psi not the sort of thing you can do at home in a spray booth also the
structual stuff is usually made from pre-preg fibre which is very costly.
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mranlet
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| posted on 8/8/03 at 03:26 PM |
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Hmmn... the 150psi would be tricky...
I'll have to think about it...
Thanks for the info
-MR
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DaveFJ
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| posted on 8/8/03 at 04:17 PM |
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I order to carry out repairs to compostie structires on aircraft we use a dfevice called an hot bonding controller. it is a ver involved proces but
the end results can be very strong and also neat...
Basically the piece is layered up in the normal way. then you apply a release film followed by some matting that will allow the air to be drawn out.
then a heater mat is positioned and finally the whole lot is sealed air tight using polythene sheet with small nozzles presse through to attach the
vacuum hoses to. once all connected up the machine is programmed and away it goes. it works on the process of creating a vacuum in the work and then
heat is applied to cure in a set profile. The profiles were laid down in manuals and I cant really remember them but basically the heat was slowy
increased over say 30 mins then baked for 2-3 hours and then slowy decreased over about another hour. sometimes the manuals dictated heating/cooling
in stages. all the time the vacuum was maintained. as for temperature I don't believe we went over about 80 Centigrade. Oh yes - we ALWAYS used
epoxy resins.
anyway the point of all that is. It should be possible to create a way of performing the operation DIY style however it would not be too easy.
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mranlet
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| posted on 8/8/03 at 06:57 PM |
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If this system works, I could just lay the resin coated CF out in the sun here in Florida - the heat absorbed by the black cloth will hake it bake
itself!!
If you could get any more information on this, or specific numbers, that would be tremendous!
THANKS!
-MR
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Alan B
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| posted on 8/8/03 at 08:30 PM |
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You are in FL?
Where?
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mranlet
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| posted on 11/8/03 at 03:11 PM |
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Tampa - I remember you telling me where you were, but I can't recall...
Maybe sometime you'd be so generous to allow me the chance to see the Meerkat up close? 
-MR
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DaveFJ
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| posted on 11/8/03 at 04:15 PM |
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THIS
Is a newer version of the kit I used to use. Unfortunately there is little in the way of technical information.
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mranlet
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| posted on 11/8/03 at 08:15 PM |
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Hmmn... says ranges to 300C/600F - that's a little warmer than the FL sun (although not by much) but may be heat gun territory...
I wonder if there is a way to heat it up using electricity, like the way an electric stove's burners work... that would surely get it hot
enough...
Thanks!
-MR
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DaveFJ
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| posted on 12/8/03 at 08:26 AM |
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the device in the link uses electrical 'heat mats' made of some type of rubber so they can be flexed to fit the contours of the job. You
get a selection of sizes in the kit which can be combined to cover the whole area
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mranlet
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| posted on 12/8/03 at 06:15 PM |
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I didn't see a price on this piece - how much would I be talking about for buying one?
-MR
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DaveFJ
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| posted on 13/8/03 at 08:26 AM |
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No idea on that score - sorreee
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Alan B
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| posted on 13/8/03 at 12:17 PM |
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quote:
Originally posted by mranlet
Tampa - I remember you telling me where you were, but I can't recall...
Maybe sometime you'd be so generous to allow me the chance to see the Meerkat up close?
-MR
No problem, anytime....I'm right at the other end of rt 60 from you..near Vero Beach..
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thekafer
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| posted on 13/9/03 at 04:24 PM |
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carbon fiber
The reason the aircraft industry uses prepreg carbon fiber and autoclaves and the like is just to get the end result absolutely void free.
Another reason has to do with cloth to resin ratios(lighter/stronger).
If you live in an area like Florida,Texas,Arizona I would use an epoy resin with a high "t's of g" rating and steer clear of poly or
vinylesters.
They have a tendency to sag and take a set in the hellish heat of these states.
A wet lay-up with a vacuum bag is all you need for a car.
As for reinforcing a frame w/cfc's? In my humble opinion DON'T DO IT! (sevens fly down roads not over them)
But if you dead set on doing it.It would be far stronger to use cabon fiber panels riveted to the frame rather than laying-up around it.
You'll have to use monel or stainless rivets because carbon and anything else tend to electrolytically corrode.
By the way Birkin sells cfc noses fenders and hoods at reasonable prices.
(Rants from a guy who does'tn even have his frame finished)
Good luck!!! Fletch
[Edited on 13/9/03 by thekafer]
[Edited on 13/9/03 by thekafer]
[Edited on 13/9/03 by thekafer]
[Edited on 13/9/03 by thekafer]
I'd rather have a bottle in front of me than a frontal labotomy...
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