Fiberglass vs. Carbon Fiber
 

I'm lost on the difference in all the aftermarket stuff I see,especially spoilers and front bumpers. Can someone explain to me the difference between all of fiberglass,fibreglass,carbon fiber & carbon fibre? What are the pro and cons to each?

fiberglass/fibreglass
carbon fiber/carbon fibre

same thing different spelling. I believe in euro english they spell it "re" instead of "er", same material though. Kind of like tyres and tires.

Personally, if it were me, I'd get it in carbon fiber because, cf has the tensile strength of steel. Fiberglass tends to be too flimsy and brittle.

Don't forget OEM parts as well - poly resin. Fiberglass is light and cheap - racers use it because of those reasons, and often racers have extra body parts with them at the track when they get hit, because fiberglass will shatter. It's not desirable for a bumper if you drive on the street. Whereas an OEM (poly) bumper may crack or dent, a fiberglass bumper will crack and shatter - far more damage and much larger crack than the poly bumper. Carbon fiber is the lightest, but also most expensive, and near impossible to repair properly.

Thanks for the input! So does anyone see a problem with putting on an aftermarket rear spoiler made out of fiberglass on a Boxster?

Fiberglass
A fairly generic term in which you take fiberglass mat or cloth and lay it up with resin to form nearly any shape. Found everywhere, boats, surfboards, airplanes, car bodies, rocket motors, space shuttle etc.
Pros- good strength to weight, easy to work with, can be made very flexible,low cost.
Cons- repeated flex can cause failure, gets brittle when uncoated/painted and exposed to sunlight. Glass fibers get in your skin when sanding and make you crazy.

Carbon Fiber
The same basic process as fiberglass only using carbon fiber cloth and high quality resins to get the highest tensile strength, highest strength to weight, and achieve a very rigid shape or structure.
Pros- Ultra high strength, ultra rigid, resists damage from sunlight when unpainted.
Cons- does not flex, if flexed it shatters like glass. very expensive.

Traditionally this was only found on ultra high tech applications (fighter jets, space shuttle, F-1 race cars, world class racing yachts) due to its high cost. It is now much more mainstream (even NASCAR bodies use carbon fiber now I think) and has become a fashion accessory of the Rice racers and others who have body and dash panels laid up with carbon fiber just for the look. Most of these panels are not pure carbon fiber but common plastic/metal panels with carbon fiber skin. No lighter in weight or stronger than fiberglass. Just pure bling. All foam...no beer.

So do you want carbon? Is ultra high strength/ultra rigid important for your application? If so then carbon fiber is the way to go if you can bear the extra cost.

Just get the Ruf. They actually test their stuff. You will be glad you did.

fiberglass is hit or miss.

Its only as good as the shop making it. I had a fiberglass aero kit on a previous kit made by Racing Beat who specializ in RX7 and Miatas and it was well made stuff. I spoke to someone who once worked there and they told me they threw out a great deal of product that didn't meet quality control standards. He said he bought allot of rejects for his own cars because it was a matter of minor blemishes imperfections that could have been fixed with a little time.
98% of Fiberglass makers will not be so attentive and will use as low grade materials as possible.
This means horrible fits where body panels don't line up properly and since most of these aftermarket parts are on sport suspensions they end up taking lots of punishment...paint starts to crack and looks like a wrinkled shirt in no time.

Now Composites like carbonfiber are another matters. It's a fairly low tech manufacturing procedure and risky for craftsmen to work with. Thus you don't see allot of genuinely well made carbon fiber. I was one of the first among my friends to buy an all carbon bicycle back in the very early 90's and it was actually made in Taiwan by Giant! I turned away from expensive aluminum because of its short shelf life. But as far automotive, it still seems to be standard for everything from ultra expensive racing helmets to mirrors.

Polyurethane, polyresins etc. used in factory aero parts from Porsche are well made, resilient and lazer cut so there's never an issue with fit. But its very expensive.

I'm pretty sure this bumper is fiberglass.
http://uplode.us/images/6608crownboxster.jpg

i take exception to the last statement. carbon fiber can be designed to flex very well (think golf club shaft or corvette leaf springs). CF properties can be greatly varied depending on the manufacturing methods (resins, mold types, cure method, etc.).

^ very true you should see my carbon fiber bicycle's rear triangle flex when out of the saddle hill climbing. These guys can do amazing things nowadays.
But ohh so expensive. I lusted after a Fondriest frame made from F1 grade CF (they had a former F1 Ferrari engineer) but they couldn't make the darn things for less than $6K and eventually went out of business. Too bad, best bike I ever owned (partially CF).

Insite,

You are right. I forgot golf shafts. My experience with CF was on racing yachts where it was chosen and designed to eliminate flex.

For a spoiler, fiberglass is just fine. No advantage for polyresin on that one.

Regarding carbon fiber and composites, I wholly disagree that it is a 'low tech' process - if done poorly, it is, but done correctly, it is VERY high tech, and difficult to do. Those who do the half-ass method of just using resin and drying in the open air are just making fiberglass with carbon fiber sheets. True carbon fiber and composites must be cured in a heated vacuum, and that is what makes good carbon fiber what it is.

i've heard the mount holes on some of the aftermarket spoilers crack out after time. i believe there was a thread on here a couple weeks ago about it.

If you/can you paint the carbon fiber what will the finish look like? Will you see the fiber or can it be matched in a smooth finish like the bumper?

Yes, you can make a super smooth finish.
It depends on the tooling/cure process, fill & sand, and the desired finish.
Most composite components will need some sort of buildup, insert, or stiffener in the hole areas to prevent cracking.

BTW...fiberglass is a composite material too!



:cheers:

Interesting. I was wondering because I love the rear diffuser bumper but have not heard good things about the fiberglass diffuser add ons.

Very informative thread! I was looking at some bumpers on Mashaw's site but only fibreglass or carbon fibre are available.. from everyone's experiences what would be more suited to a street driven car?

urethane or FRP. they're flexible. carbon fiber is good, but usually the layups are not done in a manner condusive to high flexibility. cost is also prohibitive, and unless the vacuum bag / autoclave process is sound, they'll have to use too much material, negating the weight savings over fiberglass, FRP or urethane. plus, much of the carbon fiber stuff on the market is actually fiberglass with one outer layer of carbon fiber fabric for looks.

Hi,

The term Carbon Fiber encompasses many different materials and processes - too many to discuss in length here.

Most CF on the Aftermarket is not pure CF, but (CRP) Carbon Reinforced Plastic. The plastic is most often epoxy, but other plastics, such as polyester, vinyl ester or nylon, are also used. Some composites contain both carbon fiber and fiberglass reinforcement. Less commonly, the term graphite-reinforced plastic is also used.

One way of producing graphite epoxy parts is by layering sheets of carbon fiber cloth into a mold in the shape of the final product. The alignment and weave of the cloth fibers is carefully selected to optimize the strength, stiffness, or flexibility of the final product, depending upon it's application.

In demanding applications, all air is evacuated from the mold, but in applications where cost is more important than structural rigidity, this step is skipped. The mold is then filled with epoxy and is heated or air cured.

The resulting part will not corrode in water and is very strong, especially for its weight. If the mold contains air, small air bubbles will be present in the material, reducing strength. Most composite parts are manufactured by draping cloth over a mold, with epoxy either preimpregnated into the fibers (also known as prepreg), or "painted" over it. Hobby or cosmetic parts are often made this way, as are high performance aerospace parts. High performance parts using single molds are often vacuum bagged and/or autoclave cured.

There are very few Aftermarket parts which are made of CF or CRP which are produced for anything more than the 'Trick' look and so are pretty cheaply made - no vacuum or heat. These pretty much perform on par with fibreglass and don't offer any real strength advantages, though they are slightly more robust - but only slightly due to the amount of air bubbles (mostly internal and not visible) they contain.

Happy Motoring!... Jim'99

I agree, urethane for the bumper.

cf is stiff, light weight, and well suited for many applications. But it’s probably not what you want on the street, due to initial cost, and high cost of a specialty shop doing repairs, if an unfortunate event were to occur. It also must be kept from UV, with some sort of protectant, which normally negates the "cool factor" of the exposed weave of the fiber.

One other thing...cf is not corrosive by nature, but when in contact with AL and moisture...you will have an electrolysis effect with the metal. The contact area must be protected using fiberglass.

The choice is really up to you. :)

:cheers:

Why is it so expensive? the build process doesn't strike me as very scientific and the materials are hardly exotic.

Hi,

There are a number of reasons and it's getting even more expensive.

First, it is very Labor Instensive, not an easily automated process.

Second, the cost of producing Molds for limited production runs equates to a high cost/unit.

Third, and increasingly so, while the demand for Carbon Fiber increases, the Supply of Carbon Fiber is decreasing due to the high demand from Contract Consumers causing the price of the Raw CF Fabric and yarns to shyrocket. The market price of Carbon Fiber reinforced plastic saw a 150% increase during 2005, primarily due to increased use in the Civil Aerospace industry.

Allocation and contracts to Boeing Commercial Airplanes' 787 and Airbus' A350 XWB and A380 caused supply constraints, and suppliers raised prices to suit. As the aerospace companies were locked-in with long-term contracts, users of Carbon Fiber Reinforced Plastic in other applications have suffered the brunt of this price hike. In fact, 6 of the 9 top producers of Carbon Fiber are now dedicating 100% of their output to fulfilling these aviation contracts, and will for the next 4-5 yrs. This essentially reduces the availability of supply of Carbon Fiber to the rest of Industry by 2/3.

There are a number of Companies working to make Carbon Fiber less expensive through newer Oxidation processes. Carbon Fiber is generally created from plastics such as Polyacrylonitrile (PAN), a polymer based on acrylonitrile, Rayon and Pitch. These are all derived from Petroleum, and so the price of Oil is another factor in the final price of CF.

These materials are then oxidized through Pyrolysis - the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam (think pure, complete Burning). This process leaves only the Carbon as a residue, and is essentially the same process used to make Charcoal and Coke. These materials are used because they generally yield about 98% of their initial weight/mass as pure Carbon. This requires large, specialized, machinery such as very large Autoclaves, as well as large amounts of expensive Energy.

But, Research Labs, specifically Oak Ridge National Laboratories, are working on making the molding process more efficient and cost effective by introducing methods which can be done robotically see - http://www.ornl.gov/info/press_releases/get_press_release.cfm?ReleaseNumber=mr20060306-00

Happy Motoring!... Jim'99

"Allocation and contracts to Boeing Commercial Airplanes' 787 and Airbus' A350 XWB and A380 caused supply constraints, and suppliers raised prices to suit. As the aerospace companies were locked-in with long-term contracts, users of Carbon Fiber Reinforced Plastic in other applications have suffered the brunt of this price hike." --wikipedia



Thank god for Wikipedia, you can also see how the Carbon Fibre structures are made for a popular supercar on youtube.

aside from materials, the build process to PROPERLY create carbon fiber components, especially structural components, is quite difficult. much of what's on sale in the way of body panels, bumpers, interior parts, etc. is made in more or less the same way as a fiberglass part. in this case, it's not much stronger or lighter or time consuming to construct.

on the high end, very tight controls on the mold (materials, temperature, humidity, etc.) are in place. where i work, we even went so far as to choose a metal that has the same thermal coefficient of expansion as the CF matrix has to prevent distortion.

once the molds have been created, the fabric must be layed up in a manner specific in fabric orientation (you cant' just stick the fabric on the mold). you actually have to choose in which dimensions you want the part to be strong.

application of the resin is a task in itself if one wants to eliminate porosity, boracity / de-lamination issues, etc. after the resin is applied, a vacuum bag is put in place over the mold to suck the fabric and resin together. in some instances, the CF matrix is actually under tension during this process (pre-stressed CF matrix). after this, the whole schebang is baked in an autoclave.

the methods above probably aren't used on your average bumper, but they are used in F1, carrera GT, enzo, etc.

Jim,
Did you rip off Wiki without giving them credit?? Shame on you!

Hi,

No I didn't. Someone else PM'd me about Chico's (? or whatever his name is) post, seemingly jabbing me. I didn't see it since his contributions are hidden to me. Guy must be cyber-stalking me, disecting everything I write, I dunno - his prob, not mine, I'm not concerned with what he does.

I took my post from my own notes. I've been working with CF since I was studying for my degree in Materials Science back in the '70's. Back then, there were probably fewer than 1000 people who even knew what it was.

You see, I had a small business with a partner producing cosmetic CF parts for the Lotus Esprit. I met my partner, a fellow Esprit owner, at a Nat'l. Lotus convention we both attended. We had similar science/engineering backgrounds and decided to see if we could make up some parts. That's when we contributed to the article in Wikipedia back in '05. We made contributions to the articles on Carbon Nanotubes and Pyrolysis also - this isn't the only forum I contribute to.

He was actually working for a company and had access to some mold making equipment, including a CNC. I spec'd the pieces, produced 3D CAD drawings and my partner would use these to produce a mold and lay up the piece. We made a few sample pieces, but found that using the painted or wet method produced too many rejects from air bubbles, even when vacuum bagged.

We then started making the pieces from prepreg cloth and autoclaving them. These turned out so well that our reject rate came down from 50% to under 4%. So, we started making them to order. We produced about 1000 various pieces in total. But, since we used this expensive production method, we could not really afford to continue (at a price people were willing to pay, and we sold at near our cost) since we could not reach any economy of scale without making a sizeable investment in equipment and we didn't feel the market (both demand estimates as well as competition from firms already doing this work) warranted such a gamble. But, we had a good time, learned a great deal, made several new good friends, and came out pretty much even.

I'd actually forgotten about this submission to Wiki until I broke out my notes for the current thread. Guess I don't feel the need to footnote an article I co-authored...

Happy Motoring!... Jim'99

Lol he thinks I'm stalking, I just decided to check his words against wikipedia and I just noticed that his first large reply about carbon fiber is word for word identical to thw wikipedia information on carbon fiber. Not jabing him, just think its unethical to copy and paste amounts of information like that without parphrasing it or quoting it. People get kicked out of there masters program for that kind of thing. But its a forum so doesn't really matter but I knew he didn't know everything about everything he posts... try compairing his posts to wikipedias info on carbon fiber.... word for word match on 80% of his posts here. And if he contributed his notes on CF to wiki, for someone who is anal to the max, he didnt cite himself at all in the artical

http://en.wikipedia.org/wiki/Carbon_fiber
Heres the history of contributions to the topic of CF on wiki and i see no Jim or MNBoxster listed
http://en.wikipedia.org/w/index.php?title=Carbon_fiber&limit=500&action=hist ory

I must admit, im being kind of a jerk right now so ill stop before things escalate.

Exposed as a fraud???

http://i84.photobucket.com/albums/k2...94860f9cc-.jpg

Impossible, because I'm ignoring you... Ignoring you... Ignoring you... I cannot hear you... Ignoring you... Ignoring you...

Rolflmao!
:D

CJ I think sometimes in life you have to admit when you are wrong (unless you are having a debate with Bruce Lee :D ).
Something our current Prez has learned the very hard way.

Yes, what he said. If your getting a spoiler made out of Figerglass, just make sure the mounting brackets are made well and don't crack at the base. This is why I would go with Carbon Fiber, it's less prone to stress cracks. I had a spoiler on my other car that slowly began to crack because of vibrations that were sent through it every time I closed my trunk. They started right where it bolted up to the deck lid. :cheers:

I usually do accept when im wrong quicker than anyone i know ever could. I admit i was being a jerk, cant say im wrong officially...you know the history of wiki, no jim there and he never forgets stuff, so how would he forget he posted that info word for word in wiki.... I find it strange, is all. :) I couuuuuuld be wrong but thats as far as ill go on record of admission or wrongness haha no big deal though really, Im looking for another thread to respond to today, this on is done :D

MNBoxster supplies some very useful and informative information to this board but I'd be more impressed if he'd reference his sources. This isn't the first incident.

Hi,

First off, I feel no great compulsion to prove anything to anyone here. My posts are my posts, believe them or not, it really makes me no nevermind.

That said, there are, IMHO, several members here who personify Equine Excrement Expulsion Orifices, or E³Os. It’s not necessary to identify them here. These people are Haters, and I just have no time for them.

So, to gain the most from my Forum time, I simply employed one of the tools the Owners have availed us and placed these people on my Ignore list. This way, I do not have to see any of their contributions when browsing threads, as I don’t give a damn what they say anyway.

This works quite well, and I wouldn’t mind one iota, in fact I’d welcome it, if they were to reciprocate and place me on their Ignore lists. This would surely save a wealth of hassle. But, as they relish controversies as much, or more, than content, I doubt it’ll happen.

To the issue at hand, I did co-author this article on Wikipedia. In fact, I made several contributions to it. I’ve been in the Car Hobby for many years and have vast notes of all type. When answering a thread, I often cut & paste from these notes as a matter of expediency, such as I did in this case. And, point of information, Wikipedia is not to be considered a tertiary source, and consequently, really does not require a footnote anyway.

But, I am also an author. As such, I often use nom de plumes when on the internet because this is my private time, and I rarely want to be identified with my professional work. Consequently, I don’t use anything associated with me when on most sites, Wikipedia amongst them.

For that, I took no user name and simply let my IP address suffice as my identifier, similar to many other Wiki contributors, it’s not at all unusual. And, if anyone were to care enough to check, I’m sure you’ll find only a handful of contributors at best who made contributions to those articles I mentioned, and even fewer who used their IP addy as their identifier. Of course, I know what it is, but as I said, I feel no obligation to prove or disprove anything.

Impugning a person’s integrity is a serious thing and not something one should do lightly, especially for revenge as the lister alludes. So serious in fact, that there are Laws to protect people from this type of reckless action.

Of course he now wants to casually disavow any consequence for his actions and I find this to be typical of him, which is no small part why I wish to ignore his presence here. I only wish he’d do the same with regards to me.

Post as often as I have, and it’s somewhat natural some may form resentment and try to challenge you. As most of you know, I’ve taken my share. That’s part of the game, but this guy’s shtick goes beyond the pale, especially for someone who regularly, innumerably, PM’d me for advice, often within minutes of slammin’ me, if you can imagine cojones like that. So, I’m sure you can imagine that I would wish to have no association with a person like that.

This Forum has changed over the past year and not necessarily for the better, partly due to people like this. IMHO, it’s becoming increasingly a gossipy Tea Party, with personal attacks and innuendo on the rise. A real shift in the demographic. So much so, that several contributing members just don’t visit regularly anymore. I’m seriously debating how much of my future free time I want to devote to it.

To quote Forest Gump: “And that’s all I have to say about that…”

Happy Motoring!... Jim’99

In a world only you know.

Prediction ...

... locked thread.

Yo CJ,

http://i84.photobucket.com/albums/k2...est-waders.jpg

I'm considering a group buy. What do you think? They'll allow us to read the forum without getting bull doo doo on our pants.

Signed,

Ernest Hemmingway

I think ill buy into that group buy, count me in.

I may need a pair or two of them things too...Grizz whats the MSRP on one of them theres suits you gots?


Edit: Just to keep things on topic.....Does that jumpsuit come in carbon fiber?

lmao!!! :D