Shug.
Has anyone tried panelling a locost (or similar) chassis in CFRC (Carbon Fibre) sheet insted of Aluminum? If yes what thickness was used and how was it attached (riveting?). From wher was it purchased and at what price?
quote:
Originally posted by phil_far
Has anyone tried panelling a locost (or similar) chassis in CFRC (Carbon Fibre) sheet insted of Aluminum? If yes what thickness was used and how was it attached (riveting?). From wher was it purchased and at what price?
Here you go - half way down the page is a carbon bodied westfield
Fluke Motorsport carbon bodied westfield
Big bad monster expensive spec on everything.
the same car is in this months track and race car mag.
wow it must be at least 1kg lighter
Try BRP Composites, Neale is very helpful & the prices will (pleasantly) surprise you.
I had a few square metres some time back
BRP Composites
Fox Barn
Pepperharrow Park
Godalming
GU8 6BQ
01483 861212
info@brpcomposites.co.uk
I don't see any real advantages to using carbon in the place of aluminium for the application. If lightness os the concern, then I'd suggest carefully selecting where to go thinner, or perhaps sandwich type panels. Thin carbon panels are not going to be much, if any stiffer then aluminium, more prone to cracking and there is always the issue (arguable, but well supported both ways) of the corrosive nature of carbon-steel junctions. Frankly I think you'd be better off molding the cowl, bonet and nose in carbon, as those are easier to do, non structural and higher on the chassis than the shear panels. But thats just my two cents. Cheers!
If those carbon panels where glued onto the chassis with the correct glue, then that would make the chassis alot more rigid. Ally is very soft in
every direction, carbon isn't.
There's one advantage anyway,,, oh yes and it looks as SEXY as hell.... Thats 2
I am not sure what grade of aluminium you all use but I would suggest that a high grade such as 5251-H22 (NS4) would be easier, cheaper and probably
lighter and stonger than carbon.
Aluminium sheet has come down in price recently I pay around £15 for a 2000mm x 1000mm x 1mm sheet from Baco Metal Centres.
Use proper rivets (not soft aluminium) and bond to the chassis and it will be very strong.
I have done carbon panels. You require at least 2 layers of carbon at around £15 per metre square, plus gel coat and resin. Also it is messy and
smelly.
Leave the carbon for curved panels.
John
Lets see....Carbon is extremely soft in most directions that do not lie along its axis. That means its anisotropic and difficult to model, especially for backyard use. Carbon isn't great in conpression, thats another thought. There are reasons that in structural cases its used in sandwiches, unidirectional reinforcement and cables. In non-structural applications you can use it however you want. Personally, I think a mild alloy like 6061 would be rather well suited (relatively high strength <as good as mild steel and then some>, easy forming in "O" state, good machining and weldability). Oh, and it is much closer to steel in the galvanic reaction tables then carbon, which means you won't have to rebuild the chassis every few years (unless you made the chassis out of Titanium, which is pretty close to carbon). But, ya builds your chassis, ya takes your chances. Cheers!
PS, I strongly agree with JB on the use of proper rivets (cherry Q, not N, or equivilant would be a good place to start) and bonding with a good metal to metal agent. Quick note, even with bondingm even if confident in its strength alone, always rivet the corners, as bonding is not so great in peel as it is in shear. And peel always starts at the corners. Cheers!
You tell em Syd I'll buy that fer a doller
Shug.
I maintain what I have already said. But frankly I don't feel the need to argue it further. I've done the analysis, I've done experiments. But out of curiosity, how thick are you making your lay-ups (5.7oz cloth about 7thou) and what bonding agents are you planning? And since you want to lay it up -45/45, you get better interlaminar strength with uni running 90deg to each other than two like fabrics on top of one another. Of course a symetrical layup about the center layer would be a good idea. I happen to work with composites as well, and have immense respect for them. I don't think they are the perfect material for this application though. Happy building!
Syd i just think he was a bit miffed that you were accusing of being an 'armchair expert' when infact he too works with composites so is
probably just as clued up as you when it comes to these matters. And to be honest i think he desrves a bit of an apology....
I dont know anything about composites but, i have seen sevens done with carbon bodywork. How good it is i dont know. I think it would only save
minimal weight (yes i have done the weight calcs too!) And IMO not really practical for home locosting. If you (apparently) have the skills, great,
use them. If not then stick with ali....
Cheers,
David
Maybe he is just asking your opinion on what layup to use. And looks to me the was suggesting +/-45deg. (It makes sense to me too).
Maybe we are reading it different ways, i dunno.
I must admit, the statement 'layup from corner to corner' did read to me like diagonal.
I've used alu, so I dont give a crap either way 
atb
steve
quote:
Originally posted by F1 Mini
If those carbon panels where glued onto the chassis with the correct glue, then that would make the chassis alot more rigid. Ally is very soft in every direction, carbon isn't.
quote:
Originally posted by F1 Mini
There's one advantage anyway,,, oh yes and it looks as SEXY as hell.... Thats 2
Kylie is better than Maggie in every way. Kylie could have probably even run the country better than her!
Cheers,
david
I read exactly what you said Syd, and for the most part did agree with you, except in it being an ideal application. That was a question I asked however, simply implying that I'm resigning myself to the fact that people will use carbon and asking what your proposed fabric cloth weights, resins and bonding agents were. I figured if I knew that, I might be able to at least better understand your position or discuss on that basis rather than carrying on a pissing contest. But whatever, cheers!
Carbon composite panels are not everyones cup of tea, indeed if they are subjected to overloading beyond their design limits, as has happened in the
aero industry (747 tailplane delaminated in yaw), and an Infamous trimaran that fell apart a couple of years ago. When it fails its dramatic and you
dont get much warning. In both cases the design had been subjected to computor modelling that failed to recognise loads in extreme emergencies and in
the case of the boat, failed to take into account the loads the hull was subjected to when the front and rear of the hull was hanging on the peak of
two waves, and the midships section had a hole under it 
All dodgy events. Personally for the oggle factor, jaws dropping. (have a look at the body
on a Palmer car) it looks 
and just to prove I "somtimes" play with this stuff there might be a wee bit of it on my car
eventually. For cost and speed of completion Ill be sticking to side panels in ali. Cheap and fast, just like my taste in women
Shug.
Hugh, that synopsis was almost poetic. Rights reserved I suppose Cheers!
Oops sorry lads didn't mean to kick the honets nest etc. As may have said ally is alot easyer to work with and still very effective. I have
just sold my Ultima and it looked lovly inside with all that polished ally.
I just thought CF would be stronger, but I'm no expert as I havn't done any thing with it yet.
PS I do have Kylies Calender though......Lovly figre.......
So let me get this right u sold an ultima
to do somthing with a Mini, and I thought I wuz nuts
Shug.
Yes but You don't know about this yet do you ...... and yes its Kevlar and carbon.....
[Edited on 31/5/04 by F1 Mini]
And there's this little brute that's sat in my garage ready to go in it. 649bhp on a British dyno, 606Lbs...
Rescued attachment DSCF0018.JPG
Understand now.......
it all makes sense now,the mini is your shopping car
Oh yes we all understand now, You have a death wish but very impressive, hell of a way to go
Shug
A Shopping car come 10 second Sleeper. The F40 is my replacement for the Ult, but it's going to be a few years before that's complete. So
the mini realy apealed to me at a Cheap, Fun, Quick and build it yourself level.
Mad..... almost definatly....
OK, I'm hyjacking Philips post. I too am considering using CFRP for the sides, back, trans tunnel and perhaps even the bonnet. However, I'm
not really experienced with the material. As was suggested before, I plan to layup on glass, then cut to suit. But I have no idea how many plys are
appropriate. I'm thinking of using 3 plys of CFRP, with perhaps a ply of kevlar on the inside of the trans tunnel.
Is it possible to layup 4 plys in one fell swoop? I've read once that composites create chemical heat as more and more plys are used.
Also, what weights/patterns should I shop for?? Any help is appreciated!
--Chris
Chris, The carbon is reasonably easy to work with, the carbon kevlar combination requires shears with a keen edge that can cut the damn stuff, dont
even think about using the carbon/Kevlar mix without the correct tools. Ask the supplier if he stocks them he may well do. You now have to look at
what type of effect/strength you are looking to achieve. If you are hand laying this without vacuum bagging or employing someone with an expensive
autoclave as well (to hell with the expense if u do) you are simply going for the wow factor. In which case to be honest to save on cost of material
if you looked at the layup of similar products on other cars you would no doubt find the outer (visable) surface would be a Carbon weave backed up by
a couple of light weight CSM laminates, or more likely either a GRP Cloth/weave, or a Carbon/ Diolene composite (who me). If you are interested in
buying enough Carbon to do the bits u mentioned like so, its liable to cost in the region of 10-15 quid per metre of material for the Carbon Cloth,
hell of a lot less for the grp weaves or even CSM. U now have to consider which type of resin you intend to employ, Polyester and others in the same
family. or Epoxy resin, dearer but stronger less, fumes, and a bit more complicated to get the mix just right. If u have a good technique to get a
nice even layer of gelcoat on yer panel/mould to give a base for the carbon, I would say have a go. If you have minimal or no previous practise with
bog standard resin/CSM dont bother buying the carbon never mind the kevlar, u will be throwing yer hard earned dosh away. If your daft enough to try
it anyway, I can tell u where to get "samples" or swatch pads for u to have a look at prior to buying, and point u in the direction of a
supplier to save u dosh that will sell to "enthusiasts" at a reasonable cost, in small quantities. Oh make sure your sitting down when u get
the quote
Shug.
is there a cheap way to get the carbon fibre look? is the process the same as for grp ?
The process is the same its just a wee bit more fiddly to get a good surface finish with no air bubbles spoiling the apperance of the item, (anyone
got an aero)!! Flat panels are a doddle, shaped panels with flanged edges or returns etc take a bit more time/thought. If your careful good results
can be had. Its like Sex all down to technique, you get better the more u practise
Shug.
Do you have to use a gel coat when laying up a carbon/epoxy flat panel ? I thought the gel coat was just there to give a more weather resistant surface to polyester resin.
No first hand experience, but I have heard if you do up a batch of gfrp and put a bit of copy machine toner in the resin, it results in a carbon look,
without the carbon problems.
may be worth a try if appearance is the goal, instead of strength.
dave
[Edited on 11/6/04 by dmottaway]
You can buy the Carbon powder ''look'' from good GRP suppliers If u want to be a right plonker u can buy the glitter flecks to
add to yer gelcoat too.
Shug.