Can anyone share their knowledge on how to fabricate carbon fiber peices...I would love to make some stuff out of carbon fiber but I don't know how to do it or where to get the materials.

Help????

-Britain

it's like fiberglass, just easier

good source for the materials is
TAP-Plastics
we have several stores here in the bay-area ...

about $36 per yard (50" wide) (the nice Black Sort) ...

it's easier than fiberglass because the rasin is pretty much your finish if you like the black-cloth look. it soaks the rasin up very well (unlike kevlar) and a 2-layer piece is already pretty strong ...

i'm about to get started on some carbon fiber 914 pieces.

Andy

Like Andy says, just like fiberglass, but I wouldn't say easier. The fabric tends to be stiffer than fiberglass, so making it conform to a shape when wet is more difficult. Also, Andy says that it is easier because you don't have to finish it. However, getting a nice smooth finish (like we all associate with CF), is very difficult, and you will see every mistake you make.

Demick
'74 2.0

good point!
so scrap what i said about easier, just different difficult in regards to FG

I'm thinking of making my driver's door in C/F. Can the fabric be cut with my dull garage scissors like F/G fabric?

Paul

Also remember it will not be structurally strong like the carbon-fiber used for a racecar chassis...totally different animal......

a vacuum bag would help for cosmetics and to get the form near perfect for a complex part.........

yes, cuts really easy with scissors or razor-blade ...
make sure you have a respirator (sp?) as the fibers are not very good for you (just like FG, i'm sure you know)

Andy

Kevlar is real tough stuff and light.

I have a canoe made of Kevlar, in some major white water my buddy and I smashed into the rocks, broke 10 of the canoe’s ribs and caved it right in. I got up on the rock kicked the canoe and “thunk” it popped right back and we finished the trip. That was a good thing because we were about 50 miles from anything.

I’ve broken and replaced ribs on a couple of occasions, the Kevlar has a couple of crease marks in it, but I have never had to repair it.

My 17’ canoe weighs 48lbs.

Oh, they don’t call us Crazy Canucks for nothing!!!

Is that a bug limo in the picture? Six rear wheels?

Check out this page
Scroll down a bit and you'll find a couple of links to product sellers (composites)
Most of them have good info

HTH,

Jeroen

When people refer to carbon fiber, they are mostly speaking of the composite structure of aerospace and race car componets. In this context the process is to laminate CF with epoxy resin, vacuum bag the excess out to the minimum saturation point and heat cure. Makes for a hell of a strong and light weight part. Expensive.

The stuff you see on the street is just CF used in a conventional polyester lamination. A clear gel coat is used in the mold so you can see the CF. If you don't clear gel or at least paint resin on the mold first, you will have little air bubbles and surface imperfections that are usually in the lamination. You just don't notice them as much when they are buried. CF is way overrated and very rice, IMO. That is unless you do the full on aircraft technique. Just laying it up surfboard style is just poser. And not any lighter than a well made FG part. It may have more tensile strength, but what are you making anyway? Most pieces don't need that kind of strength.

i simply like the look of the black cloth.
i'm thinking about making my door-panels out of CF.
just a plane piece with the right cutouts. the complete interior of the car is black anyways,
plus i was thinking about the 911-style dash from A.I.R. in CF as well ...

strength is not a factor for those pieces, i'm not interested in making any replacements for structural items.

FG would work just fine, but i wouldn't get the look ...

Andy

Which qualifies you as a poser

cheers,

Jeroen
('nother poser - love the look of carbon weave)

look who's talking, haha, yeah baby

Together with Mueller we could start our own 914 rice club

cheers,

Jeroen

yepp, complete body kit out of black carbon fiber, 345 tires all around on 20" full chrome rims and blue neon in the exhaust pipes!

ahhh, day-dreaming ....

I appreciate all your wisdom. I have a collection of carbon fiber parts that a bug guy has made. Some of the pieces could fit on a type-4 motor. Check it out on my website.

http://www.britainsmith.com/Porsche/index.htm

-Britain

Wasn't this guy on the Pelican BBS about 9 months ago
He had the valve covers and the K&N filterhousings for the /4
He was planning to also do filterhousings and rainguards for the /6

He suddenly disapeared and was never heard from again...

You can call it rice, but try and get a "plain" fiberglas piece to look that good (stop trying, you can't )

cheers,

Jeroen

Count me in the rice mix

May I join the club too !!!

I think it is rice to use some stupid CF sticker material over original parts.

I have done some FG parts with clear gelcoat and CF as first layer material. I have used only polyester epoxy and I have not use any vacum bags. So, some seems to like they are not real CF parts. I have to agree, they are not. They are also not stronger or lighter than normal good quality FG parts (IMHO), but they look a lot better and you dont need to paint them. Only shoot one or two clear coats.

The problem in making these parts is the airbubles. The fan shroud below is fourth I did and there are still some airbubles. I know I should use vacuum, but thats too complicate to me. I dont have vacum pump and I should make new mold and so on..... Maybe some day. I just try to say that making those parts with easy way is nothing but a easy job atleast for me. It takes time and practice a lot.

BTW, look Gunnars´s fan shroud mold. It is beautiful (like all they do) ..... :sweet:

You might think twice before using CF for door panels.

In composite aircraft, CF is not used in the cockpit (kevlar instead) because of the danger of a broken CF piece.

If your car was to get hit, the door panel could shatter and the CF could do MAJOR bodily harm as it is razor sharp and splinters in a real nasty way.

Another tip if you are working with CF, use air drills rather than electric. The carbon dust from cutting CF can short out electric tools because it is a conductor.

Thats it-forget the CF door. I'll use my nice cheap 2 oz. f/g cloth. Two layers, with another 1" wide layer around the edges. I've taken pictures of the when I made the mold for the door and I'll take some more when I lay up the door. I'll show the whole process, step by step, just like Gunner. (Ha! I wish.)

Paul

Sounds good idea Paul. Dont waste your money to CF.

But, if you like, please send more pics. I am big fan of your super light racer and I always like to see more pics about it. It would be nice to see pics about your FG molds and parts too.

In that case, Kevlar would be the hot ticket, no?

Except Kevlar is expensive, ugly, and hard to work with.

From the little I know about it, Kevlar is used for impact protection (read the "canoo" post and it is used for bulletproof vests etc.) and Carbon is used for structural rigidity.

If you want your piece to work both ways, you could laminate the together...

cheers,

Jeroen

BTW... Timo, that fanshroud looks absolutly awesome!!!
Nice work agian!

cheers,

Jeroen
(another Gunnar junkie )

Yep - outer CF skin -- Kevlar inner protective layers.

Did someone say 20" Chrome?

Typical CFRP race car construction, for safety, which is now almost all components, uses primarily carbon fiber, with a percentage of high tenacity, low modulus fiber to act as basket to restrain the broken carbon fibers. (Kevlar, Dyneema, Spectra)
In a monocoque design, elements like the nose box are intended to fully obliterate, absorbing a huge amount of energy. Retaining the nose stucture to the mass of the car is critical to achieve this full effect.
By the time the impact is beginning to encroach on the driver cell, the crash is pretty serious and the obliteration of the monocoque could be disasterous, especially in the case of multiple impacts. For this reason, Kevlar, but even more effective, Dyneema, is used with the carbon fiber to act as an anti penetration barrier. The high tenacity fibers allow the carbon fiber to crumble, absorbing a huge amount of energy, but retain the mass of the structure around the driver, offering at least some protection in multiple contacts.
Most people proabably recall the horrific footage of Stan Fox at Indy, where he was effectively a driver strapped to a seat back tumbling down the front straight after an initial impact removed the front of his chassis. Modern construction techniques are specifically intended to reduce the risk of this kind of accident.
An Indy car monocoque is not as light as it could be, with manufacturing process, skin thickness, core thickness and weight and "other fibers" all mandated - For Safety.

For a club level project, assuming you have safe and adequate driver protection in the form of metal structures, the lightest and most cost effective panels, like door panels will be foam sandwich with either fiberglass or carbon skins depending on you budget.

A carbon or glass and foam sandwich door panel for a 914 would weigh about 2 - 2.5 lb without paint. This panel would be stiff enough to sanding block rub without significant deflection. The carbon will be stiffer, as a virtue of it's fiber stiffness, regardless of laminating resin or process.

Without using foam sandwich, the panel will be quite flexible and will require significantly more fiber weight before acceptable stiffness ( but still significantly lower) could be achieved.

Foam sandwich can be done at home using your shop vac and a plastic bag (not to laminate - only to bond the foam) and I am sure there would be many DIY web sites listing this kind of information. Other than bonding the foam, the whole job could be treated as a simple wet layup process and within the reach of most people. I am sure a 3lb door skin is something most people could make at home if they have the door mold at their disposal.

Regards

Hayden PTBT

For the heat curing of carbon fiber parts, what is the temperature for curing?

I'm talking about non-critical parts, not making brake rotors
(yet, LOL)

I've got an oven and an adjustable electric vacumm pump that will pump down to about .2 megapascals (~2 bar)

I'd like to do the engine sheetmetal in CF if I go the horizontal fan route.....personally, I do not like the CF valve covers...they do not dissapate the heat enough IMHO

Mike,

It depends on the resin system. Most of what you are familiar will be room temperature cure. Many of these will benefit from an elevated temperature "post cure" maybe 175°F, that will improve the resin properties and also raise the realistic service temperature.
Beyond the room temperature systems, are miriad of resins that have special process or use applications. For race car construction, pre-preg (pre impregnated fiber) resins are cured at 120°C and 180°C - 2 different systems. The higher the cure (or post-cure) temperature, generally speaking, the higher the service temperature.

There are some great LTM (low temperature mold) resins these days that will cure at lower temps (just above room temp), that allow greater lattitude in pattern construction, curing over a long time frame. Elevate the temp and these systems cure faster. In all cases, these can be post cured once removed from the pattern to achieve full mechanical properties and high service temp.
These systems have to be refrigerated, so can pose some logistics issues.

Primary factors to consider when chosing a resin system - what service temp do I need? what temp can my pattern tolerate?, there are many others, but these two initial questions head to to a specific group of products to make the additional choices.

Hayden PTBT

Does anyone ever watch Dream Car Garage on the Speed channel? In this weeks show they did a segment on how to make a mold for a fiberglass hood. They also showed how to make a vacuum bag for the mold.

I've heard of Phenolic resin being used with Carbon Fiber (for re-entry vehicle applications). Is there any advantage to phenolic for general use?

-Tony

Phenolic usage is great as an insulator between the manifold and the carbs...helps prevent heat soak so that the chances of vapor lock or fuel perculation is less likely to happen

Wow Hayden, thanks for posting. Great info!

I was just reading this about the new Carrera GT, which has a CF monocoque
It's cured between 6 and 8 bar at a temperature of 150 deg. Celsius for 8 hours

cheers,

Jeroen
(just adding some trivia info )

Phenolic resins have some of the highest service temperatures of any laminating systems. Unfortunately they have relatively poor mechanical properties, so their use is limited by this.
CFRP with phenolic is kind of oxymoron, the performance of the Carbon fibers is so high that it can not be utilized in a Phenolic laminate.
Fiberglass and Phenolic are a more reasonable match, as is Phenolic and cotton, which is the common thermal insulator for carbs, circuit boards etc.
There are some other resins with better combinations of properties and these are used for components like the carbon exhausts on the Ferrari's.
These resins, with names I can pronounce, but not spell have applications far and wide, I am sure including aerospace where they would have been developed.
Anything cured above 1 atm, will not have been under vacuum, but rather in an Autoclave, where multiples of atm. can be generated to squeeze the laminate for advanced consolidation.

Hayden PTBT

Hayden, do you need anyone to sweep up around your shop? Clean toilets? Anything? I'll work for free as long as I get to be within earshot of you








No, I'm not kidding. Look where I live
<<====

Yep, my canoe was expensive and the finish is ugly.

But it weighs only 48 lbs (my buddys FG canoe rings in at 75lbs) and it's bullet proof.