HOW TO RECOGNIZE SUB-STANDARD CARBON FIBER

Recently we have seen an increase in "carbon fiber" sheets and other products for sale in stores as well as on the web. Since the knowledge of composites and it's use is still relatively minor, we would like to give some information to the consumer so you may be aware of some of the sub-standard product that are presented as carbon fiber.

We purchased on-line a sheet of flat "carbon fiber" stock. Below is an inspection and photos of what was received.

While the dimensions were correct at 2.0" x 14.0" x 1/8" thick, the thickness tolerance was 0.041". While this is acceptable for a sheet of plywood, it is not for a fabricated composite sheet. We also found that we did not receive flat stock either, this piece bowed up in the middle by 1/8" and had a 1/8" opposing corner twist to it. Good thing we were not going to try and use it for any project.

The breakdown of the construction of thie piece is one layer of an unknown 3K plain weave fabric bonded to approximately two layers of chop fiberglass mat (chop fiberglass mat is the cheapest composite material available) with a black fiberglass veil as a backing, all bonded with polyester resin (polyester resin is the cheapest lowest grade resin available). The conclusion is that while there is one carbon fiber layer in the part, it does not have any other properties associated with it such as high strength and low weight or have any tight manufacturing tolerances. 
The conclusion is that the piece we received was not quite carbon fiber, just a sub-standard product made to fool consumers thinking they were purchasing real carbon fiber.

DON'T BE FOOLED!