Ok guys finally a topic I feel qualified to talk about. What makes me qualified? For starter I have been in the composites industry for more than 14 years. This is my profession and this is the way I earn my living. I work for the largest resins manufacturer in the southern hemisphere. And have a further 6 years experience with thermosetting and composites applications. Which includes work with carbon prepregs, infusion and hot press molding. <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /> The biggest problem with carbon and composites in general that it allows the manufacturer to dictate where, how much and how to apply the reinforcement. The reality is few composites converters are structural engineers. I have been to visit and seen the inside of over 340 factories from boat builders to the manufacturers of bullet proof vests. So how do they work out how much of what to put in and what type of resin system to use? Most don?t! They figure it out by doing their own often crude destructive tests! Or asking companies such as what I work for to do the flexurals and tensile tests. My guys are chemists not engineers. Remember the lighter it is the cheaper it is to build. A 200gram/m2 meter 12K carbon cloth retails for R400/meter in SA. In the <?: prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />USon> and china the same thing purchase in bulk will be landed at about R180/meter. The resins can cost in the order of R150,/kg for a high performance system. So if you figure that the carbon to resin ratios are in the region 40-60% fiber versus resin you can then calculate roughly that the costs without autoclaves and post curing will be about R2400/kg of carbon or so(in SA). Now that does not include the tooling and the fact that to lay up and produce a part such as a frame can take upward of 24-48hours per part! It is not like fiberglass hot press parts where you can get an item ever 7 minutes. In epoxies even fast systems are slow. You then begin to understand why these parts are so expensive. Now steel and aluminum on the other hand come in different grades and thicknesses, and often steel fabricators simply don?t make tubes or sheets bellow a minimum thickness for a number of reasons such as too thin poses welding problems etc. This coupled with the low cost of these products make them very suitable for converters with a low risk of mechanical failure. Most of the structural designing is taken out of the hands of the fabricator. You try and order a 1mm alu tube and weld it. See what the supplier says. He will get very worried? Humph much easier welding thicker and tougher tubes using less qualified personnel and cheaper equipment. You see this is not left entirely to the manufacturer like carbon and other composites. Now if it breaks it's simply the manufacturer?s fault not Carbon FULL STOP END OF THE F&c8ng discussion. How can I be so brazen? Well consider the following when used correctly by properly qualified structural engineers that have done tests the following products get made with composites. 1) Helicopter blades 2) Many airplanes components including wings for motorized gliders and twin seat planes, Masts of high performance yachts, tails (jumbo jets). Bullet proof vests, Windmill turbine blades for generation of electrical power generation, Automotive and high performance sports car bodies and chassis from upturned fiber such as Lamborghini, F1 Ferrari?s and their chassis. Motorbike rims yes motorbike rims! Also many military applications. When you find that your trek road bikes frame weighs less than 900grams---you need to get worried very worried when a 90kg chap gets on it. Quite frankly I am surprised that a 60kg athlete that races the tour de France does not breaking the frames as they get on the bikes. So for that website "busted Carbon". Truthfully if that bloke who did the website did his homework he would not have so much egg on his face. Fact is every material has its place. For example I personally do not believe that carbon should be used for MTB wheels. Why not? Not because carbon can?t take it but because of the nature, design of spokes the alu wheels can be made so light it is a better option than carbon. Also the aluminum has malleability in catastrophic impacts making it a far safer option! Now I mentioned motorbike wheels. Yep but look at how wide they are and also the overall shape as well as the sleek aggressive look. To do the same with tempered alu will be far heavier so carbon is the material of choice here. I like all sorts of materials and believe the best material for the right job. Don?t trash carbon, don?t trash steel, and don?t trash alu. Trash the manufacturer for bad selection and use of materials! The good new is composites is still evolving. Look out for Basalt fiber, half the price of carbon, almost as light but will not snap catastrophicaly. Downside is its not as stiff. But hey in composites you can combine the 2 right..00h COPOSITE- to combine 2 or more materials that compliment each other producing a structure far stronger than either materials on their own! Lesson over
