The other day here on the Forum there were some Carbon parts for sale.
One of the parts listed was not 100% pure carbon. I did not want to Hijack the sellers post and ruin a potential sale. So I figured I would make a write up with some tell tail signs of what is real or not. To help other members here on future purchases.
There is so much to list and I have been thinking about how to word it so I am making sense and people reading this post will understand.. He it goes.
Carbon Fiber it self is a man made product. Its consists of bundles of carbon woven with other bundles of carbon. Your Average weave will have 200 fibers per bundle, with a 2 by 2 weave. So under two bundles over two bundles..
There is only One way to produce a true carbon part. This is with the use of an Autoclave. Its a large pill shaped machine that creates Air Pressure as well as heat. This compresses the layers of Carbon and cures the resin. I could get more technical on this but that's the jist of it.
Types of Carbon used...
There are many types of Carbon and Resin combos for making a carbon part. The two most common are Dry Cloth, and Pre-Impregnated.
This is the first tell on what was used to produce the part.
Dry cloth is just as it sounds. Its dry carbon that is placed over the mold were the resin will be introduced into the cloth via a brush or metal roller and the carbon will be placed into position into the mold. This style will produce a weave distorted part. The dry cloth has nothing holding the carbon bundles in place. So as the resin and added into the raw carbon the brush or roller will push and pull the weave around. Think of it this way. If you took a knitted sweater and tried to pull it tight around a shape you would stretch out the sweater oddly. Same with the Carbon cloth.
Secondly Is Pre-Impregnated Carbon
This is the same Carbon as the dry cloth but with the resin already there. The manufacture of the raw carbon adds the resin in during the manufacturing process. This type of carbon can produce part with zero weave distortion. That is were the skill of the laminator comes in to not distort the carbon when placing the fist layer in the mold.
So with that here are some ways to tell if the part you are looking as is true carbon or just appears to look carbon. Just because the top visual layer is distorted does not mean the part is fake but it is a good sign that is not 100%. Ducati for example almost all there stock carbon parts have weave distortion but that is because of there process to produce parts. There parts are 100% carbon.
Generally on after market parts when the top layer of carbon is distorted its because the rest of the part is choppmat fiberglass. The part would have been produced out of fiberglass and the visual layer carbon layer ( more then likely .010 thick ) is then added over top to cover the the fiberglass and have the part appear full carbon. The strength of full carbon to fiberglass cannot even be compared.
Choppmat is what you will find in boat hauls. Its the strands of fiberglass with resin that is blown or placed by hand going in all directions. When this is used the non visual surface of the part will be painted black ( or whatever colour) and be extremely un-smooth. Carbon will still produce a relative smooth back side to the part. There may be a slight wrinkle or over lap of material. Also why paint it? Your selling a carbon part for the look and or lightness. Why add weight by painting it?
This is the thread that got me thinking about Carbon information. Look at the back side of the rear tire huger. The Vents are not even cut out like stock. This would have also exposed that is was made of fiber glass. My photos below show visual and non visual surfaces of the carbon. None look like that.
Coloured carbon is definitely not 100% Any type of colour strand other then black is either fiber glass or Kevlar. As below the yellow and black is Carbon and Kevlar.
Lastly wraps. "Carbon" wraps have become very good and undetectable to an untrained eye. This will mostly apply to online purchase. All Carbon must be covered with a clear coat. This will give the part the UV protection. The resin in the part will start to get a yellow ish tint with in 2-3months if there is no clear coat added. Regular indoor house lights create enough light out put to yellow the resin. So if you see a carbon part that is unpainted chances are its a wrap.
Below are a few photos I took today of some random carbon stuff from my tool box and work.
There is Raw Carbon, Raw Carbon Kevlar, Some Carbon parts I made, A both visual and non visual surface, as well as some parts for a current job, Clear coated and non visual surface. You can easily see the difference of the surfaces from those photos to the one posted of the rear huger for sale. As well a small mold with Fiberglass on the backside.
There are so many tangents I can go off too about Carbon, but I think I would just be rambling. Please ask any questions and I will try to answer best I can. Hopefully this will give you guys/girls some knowledge on the material to help insure you are getting what you actually think you are getting when purchasing that carbon bling.