Carbon fiber is used on many RC cars for all types of things, from chassis to shock towers. The key benefit to carbon fiber is an excellent strength to weight ratio that makes it an ideal material for race cars. Carbon fiber is made from fiber layers that are held together with a polymer such as epoxy. These layers are stacked on top of each other until a desired thickness is obtained. Once layered up it creates a lightweight rigid material that is very durable. The one downfall of carbon fiber is that the layers can separate when being impacted during a crash or hard impact with the ground. There is a way to keep this from happening and these few steps outlined here will allow it to withstand these impacts.
Step 1) The carbon fiber is cut from sheet material and therefore can have sharp or uneven edges. The first step is to take fine 150-grit sandpaper and sand all the edges of the material.
Step 2) Next, I take a permanent marker such as a sharpie and color the sanded sides of the carbon fiber. This step is purely optional but will give you a nice clean look on the finished product.
Step 3) This is the single most important step to keeping your carbon fiber protected. Run a bead of CA glue (such as tire glue) around the edge of the carbon fiber. A couple of methods can be used. The most common method is to apply the CA glue to the part and then evenly spread the glue around the edges using a cotton swab. The CA will help bond the fiber edges together that have been exposed when the material was cut from the sheet. At this point you are all done and your towers are protected.
Step 4) After Step 3, the following steps are all optional and will only add to the appearance of the finished product. Once again, you can use fine grit sandpaper (200-400 grit) and lightly sand the edges once again. Use very fine sandpaper. You are not looking to take off the CA glue but simply to smooth it out to get the sides as smooth and even as possible. You can add more CA glue and re-sand as many times as you desire for the best possible finish.
Step 5) Again, this is a purely optional part of the process but once the CA glue has been sanded smooth, you can use a polishing compound and a soft rag to buff the sealed edges of the carbon fiber. This does nothing to add strength to the part but simply gives it a nice shiny finish.
That is all there is to finishing and protecting your carbon fiber pieces. The main goal of this process is to apply the CA glue to the edges of the carbon fiber to keep them from separating during impacts. Also note that CA glue should be reapplied to things like shock towers after the glue has been scraped or worn down from hitting the ground during crashes. Reapplying the CA glue will ensure that the sides are always protected and will keep those expensive carbon fiber pieces intact.