How it works
Carbon Fiber in its dry fabric form is soft and pliable. It's actually just like any cloth, except that it happens to be comprised of thousands upon thousands of strands of fibers woven together. Our MINI and BMW carbon fiber uses what is called "3K twill", which means that 3000 fiber strands are in each woven cord, and our Ducati carbon fiber utilizes what is called a "plain weave" to match the plain weave that Ducati Performance puts out from the factory.
To make this fabric into a functioning piece, several processes are used (as seen below), all of which basically do the same thing; harden this fabric by incorporating an epoxy (glue) into the material, laying the material into a mold (in the shape of what you're producing), and using heat cure the epoxy. There are several ways to do this, as outlined below, which result in Carbon Fiber products of varying weight and quality. To make sure the epoxy stays inside of the fabric, compaction (pressure) is needed while the epoxy is curing. Lack of compaction leads to pinholes, delamination, and weak components.
Why some carbon fiber turns yellow
Carbon Fiber which uses a poor or medium quality manufacturing process often turn yellow over time with exposure to UV rays and heat because of the clearcoat finish used during post-production. None of our Carbon Fiber use this process, as they are all top quality appearance grade items right out of the autoclave.
Methods of Production, from poor quality to high quality
Poor Quality Carbon Fiber products are often composed of mostly fiberglass and one or two layers of actual carbon fiber material. Often, insufficient compaction on these parts during the curing process leads to pinholes, resin pooling (milky buildup), and an unsightly finish which needs to be sanded down and sprayed with a clearcoat post production. The Result: These pieces are often as heavy as the stock component they are replacing, and often end up delaminating (The epoxy will separate from the carbon fiber) and/or turning yellow because of the post-production application of clearcoat.
Medium Quality Carbon Fiber products use what is called "Pre Preg" carbon fiber. Instead of coating dry fabric with epoxy, as the poor quality wet lay-up method above often uses, a more expensive type of carbon fiber that already has the epoxy embedded into the material is used. Gigantic rollers pressure-inject dry fabric with an epoxy that will not delaminate, and the result is carbon fiber which does not have to be slathered with epoxy in order to cure. Medium quality carbon fiber may use a moderate amount of fiberglass to reinforce the component, and the method of curing with medium quality CF is usually done in an oven similar to the poor quality carbon fiber. The Result: Lighter weight pieces than poor quality CF, however the curing processes used can still lead to pinholes and a rough surface. To make up for the poor surface finish out of the oven, medium quality carbon fiber is usually sanded down after it is cured and sprayed with an acrylic clearcoat to give it a deep look. The problem with this is that it leaves a nice thick layer of clearcoat for UV rays to turn yellow.
High Quality Carbon Fiber products use pre-preg carbon fiber material laid up into molds which can withstand high temperatures. The majority of the piece is composed of pure carbon fiber material. The pieces are then placed into an airtight bag, and a vacuum is used to suck out all of the air. After this, the pieces are placed into a special oven called an "autoclave," which gets hotter than a conventional oven, AND has hoses inside which hook up to the vacuum bag to continue to pull a vacuum on the piece. The Result: Because of the vacuum bagged autoclave process providing perfect compaction on the carbon fiber piece, the resin inside of the pre-preg evenly flows to the top of the component being manufactured. This results in a beautiful pinhole-free finish which does not have to be sanded down and sprayed with epoxy. Because of this, our carbon fiber components do not yellow or discolor, and are of the highest quality on the market.