Carbon tech

One of Password:JDM's curing ovens for large size parts. In this oven, parts as large as Andy can be cured.

If you have been into this scene for very long, chances are that you might have some carbon-fiber parts on your car. Do you know what carbon fiber is? Do you know what makes it special? Do you know how carbon parts are made and how that affects its performance? If you are interested in all of that, read on, we hope we can explain some of the intricacies of carbon parts and carbon construction techniques.

You might think, carbon fiber is carbon fiber and it's all the same. If you want something made out of carbon just go to eBay and get the cheapest thing right? WRONG. Like a cat, there is more than one way to skin carbon fiber and there are cheaper ways as well as better ways to do it.

Well you might want to know what exactly carbon fiber is and why it is rad stuff. Carbon fiber is amorphous carbon, which means its molecules are arranged in a random interlocking manner making the overall material very strong. This differs from other arrangements of carbon molecules like graphite where the molecules are laid on top of each other in a regular crystalline pattern making it soft so you can write on it with a pencil.

Inside the oven, there is a vacuum manifold and hoses for sucking the air out of the parts to be molded while they cure.

Carbon filaments are made by the oxidation and pyrolysis of polyacrylonitrile. In English, it is like baking kinda the same stuff your socks and sweaters are made of until it chars. Polyacrylonitrile molecules are formed in long chains that when heated in the correct conditions (usually in a pressurized methane rich environment like Andy's underwear), the non-carbon parts of the material evaporate away forming chains of nearly pure carbon molecules in the form of hollow filaments of carbon left where the threads of the polyacrylonitrile material were. These filaments are then spun into thread or yarn and then woven into carbon-fiber cloth. This is much like how the more common fiberglass cloth is made out of fine fibers of glass.

So now that we've probably caused your eyes to glaze over, let's get to the real reason why carbon stuff is so prevalent in the high-performance world. Carbon fiber's most important attribute is its mechanical properties. From the chart below you can see that carbon fiber is three times stronger and four times lighter than steel:

Chef Andy, as my photographer's assistant, helps to illuminate rolls of raw carbon and carbon Kevlar material at a layout table. Here the materials are cut into a rough shape before they are laid up. This saves time in the production process.

Sometimes the carbon filaments are combined with other fibers to alter the properties of the finished material. Kevlar, the ultra strong fiber used in bulletproof vests, is commonly combined with carbon to make it more impact and abrasion resistant. Spectra, another ultra-strong fiber, is sometimes used in this way. Boron can also be used to make the material stiffer. For the most part, in the automotive world Kevlar is the most common fiber to be combined with carbon.

Carbon-fiber cloth by nature is soft and floppy. To make it stiff so that useful stuff can be made out of it, the fibers within the material have to be locked together in a matrix. Usually that matrix is a plastic resin. The carbon cloth is soaked in resin and laid in layers to make a laminate of carbon-fiber cloth bond together with resin. When the resin cures or hardens, you have a stiff strong piece of carbon-fiber stuff.