Making Carbon Fibre Items

[AzzurrA]

Hi All,

Was wondering if anyone has had any experience with making carbon fibre (or fibreglass, for that matter, as its a similar sort of technique i believe) items?

Are there any good websites etc that outline the best way of doing things?

Now, i understand the basics, ie:

* You need to make a mould of the item you wish to replicate, mould has to have a very good finish on the inside etc...

* You need carbon fibre sheets or matting, lay it in mould

* You need resin to impregnate the fibres

* Allow to dry

* ?

* Profit

I'm only looking to make very, very simple (automotive) items to start off with, and its mainly for my entertainment/use..

Anyone with any ideas etc?

Many Thanks

Jason

[JCMarshall_Law]

It is really not hard to do wet layup carbon work, I've made quite a bit of carbon fibre bodywork, mostly when I was in the Qni of QLD Formula SAE team. You have pretty much got the procedure right. Just take a look around the web.

I'm currently making a set of carbon wheels (outters only) for a client, that is a bit more tricky and a LOT more expensive. basically the same layup procedure but everything is vacume bagged and cured in a special autoclave.

CG composites in Eagle farm are good and will get most things, a couple of the V8 teams buy their carbon/kevlar from them. The carbon and resin for the wheels were supplied by the client but I'm pretty sure it came from the states and we are talking hundreds of $ per L for the resin.

Edited March 10, 2006 by JCMarshall_Law

[yug_r34]

JC, Interesed in doing c/f tailshafts?

Edited March 10, 2006 by yug_r34

[Master]

Hi, im sure ur going to find alot of do's n dont's on the web with regards to carbon work, but since ur new to it and wanna make some relatively simple stuff, just remember a few simple rules... if you want reall good shiny bits, try using metal moulds that are well polished and free coated. N remember to have draft angles to be able to pull the thing out , otherwise it results in alot of swearing n heartache.

It would seem ur interested in making non structural bits in which case u could get away with a non epoxy based resin (cheaper!) . Also remember the direction the fibres run in make a significant difference , the 2 options are a 0/90 orientation or a 45degree orientation.

If u can actually vaccum bag ur wet laminates, u will end up with a nicer quality laminate. Try avoiding sharp corners in ur mould design, if its gotto be there then take added care when u actually lay it up otherwise ur gona end up with whats known as bridging. Id first be laying up a few flat panels to get a feel of what its like n then go from there.

N yes working with glass fibres is very similar, many people use carbon as their first layer and bulk up the middle layers with glass then finish up with carbon again, this way they get their desired thickness, etc n it works out a lot cheaper than just layers of carbon... i could go on about this...dont wanna confuse u..

[AzzurrA]

You're not confusing me in the slightest, feel free to go more in-depth into it if you wish!

found a page that was rather good in explaining how to do basic stuff (http://www.mci.i12.com/carbon/) (i'm only looking at doing some simple stuff at the moment, such as an a-pillar trim, or stereo surround etc. until i get the feel for how to use it properly) so you're right, i can use the 'cheaper' resin, and direction of the fibres doesn't matter too much, as they're purely aesthetic at the moment, and wouldn't require any strength...

[midnight]

for carbon use epoxy based resin.

cheaper poly resin even though its easier to work with tends to be abit yellow, and doesnt offer UV protection (wher as you can get epoxys with UV), so the carbon can fade after some time.

Id suggest you practice first with fiber glass and a poly resin before you start on carbon as fiberglass cloth and mat are much cheaper, where as carbon costs quite alot, especially for twill weave.

[Master]

Hi Jason, the direction of the fibres on the first layer is upto ur preference as far as what u think looks better, certain weaves a 0/90 orientation is the ticket.. What happens after that layer is critical. U have to have a balanced laminate, which is to say if ur laminate is 5 plys thick n they are all carbon then

ud go....0/90, 45,0/90,45,0/90 ...if u did 0/90, 0/90,45,45,0/90 or along those lines then an unsupported straight section could turn out to be not so straight.... For something like a stereo surround that did not need to support anything id be inclined to go with 3 layers. Also remember to have the trim lines and mounting for ur components given good thought. For example you could as part of ur lay up have an Ally insert that u can drill n tap into rather than have holes that are visible from the outside. or bond on a metal fabricated brkt .. the message is for thought to go into the entire manufacture n what happens later... no point havin shinny nice bits that then get drilled into just so u can mount em!!

I am a FSAE graduate too...

[AzzurrA]

yeah, i was already thinking of how i could incorporate the screws/brackets... takes a bit of thought to get it right though!

[JCMarshall_Law]

Hey, I got some interesting news from a few ex FSAE mates, apparently Boeing and some other aircraft manufacturer are buying up the worlds supply of carbon fibre. The new planes have a ship load of carbon in them. So all the smaller suppliers (eg CG composites) are having a lot of trouble getting anything and prices are skyrocketing. I used to buy plain weave, 120g/m2 (I think???) carbon for $26/m now we are talking over $50/m.

So all of a sudden carbon work is looking very expensive again.

As someone said, use epoxy based resin, no point using poly resin with carbon, might as well use fibreglass if you skimp on the resin.

The other thing I found is that generally carbon is easier to use than fibreglass (depends on type of weave though) because carbon more easily moulds around corners.

yug_r34, yes I would be interested in working on CF tail shafts, that is something I did not actually think of branching into. I'll send a PM.

[AzzurrA]

JCMarshall_Law... i see you're in brisbane too... next time you're doing some carbon work, gimme a yell (if you want to, of course) and i'd like to drop around and see how it all works etc

Again, thats if its okay with you

Thanks

Jason

[maximumrpm]

ive also been considering making exterior parts for r33 and r32 skylines...im very interested and also in qld if you guys want to get together with some plans....cheers

[AzzurrA]

Maybe we could start the "Consortium of Skyline Owners for Carbon Fibre Items" or something

[maximumrpm]

hehe that would be great

[Craved]

any specific wax's recommended for the release agent?

and atleast 4-5 coates? buffed back like a car wax

[midnight]

yeah use mold release wax, u can get it from fiberglass suppliers.

[Master]

Also depends on the mould, if its a composite mould to begin with, it should ideally be sealed with a sealer and then mould released... If ur makin a few bits then id be using something called Frekote. Alot less labour intensive than buffing the wax, however it is more expensive. As a general rule once you have a good mould and its sealed, the first time you take part off it ud use have 3 coats of frekote and after the first parts are off the mould just a general clean and one or two coats depending on confidence levels!!

[Craved]

yeah already got the wax, just making sure lol

only making one off things mainly, and flat panels on glass

[chch34]

im making a bunch of things for R32 skylines at the mo. more than happy to answer questions. best advise, get a vacuum pump! awesome for tricky projects!!

[Craved]

what does the vacuum pump actually do? why does it make things easier?

[Master]

Well as ur gona find out soon enough, when things are'nt as simple as flat panels and u have tight corners to get around the fibres dont always wanna play ball n stay where they should. So after u finish laminating ur part you then put on a release film, then some breather (which basically spreads the suction around ur part and absorbs excess resin too) and then bag it. So what u end up with is the better part of 1 Bar of pressure all over ur part. For a flat panel what id do is have another flat surface that is waxed to put on top (make a sandwich of the laminate) and then add some weight on it, this basically gives u a thinner better consolidated laminate. The vacuum bagging method is great but it also means buying the extra's that go with it. (Release Film, Breather, etc)

Clearly money well spent if u wanna make trick bits. All the best !!! Make sure u use gloves n have some acetone handy to wipe up the spills.