For making graphite-coated axles, it is the same simple process as making coating bullets with moly. First you have to prep the axle to the level of polish you desire. Next you basically impact the graphite into the pwd axle with steel tumbling media. It will require more costs to invest in getting the right equipment than the average.
You will run through just by spinning the wheels at home. The flake graphite is never applied in rotational layers needed for your car to perform at its top potential. You can review many comments on multiple sites that will tell you they are good for a few races, but lose their edge after a few runs. Since most pinewood derby cars will race at least 6 times or more to compete to the finals, you might think about a different way to make those axles faster than buying a gimmick.
The impact graphite application for pinewood derby axles does not yield the same results as applying the graphite to the plastic wheel. Most believe since the pinewood derby speed axles are coated with graphite, no additional work is needed. In fact, this is wrong. We have tested many different methods from burnishing, to high levels of polish. We have tried many different lube graphite coatings from firearm lubes to state of the art nano-lube applications. There are really not too many applications of spray on graphite that really work to your PWD car advantage.
A flake graphite coated wheel will yield better results than graphite coated axle for the simple reason that the graphite does not apply well to metal surfaces. We feel that graphite sticks or applies better to the plastic wheels than the metal axles.
Finding a sealant or wax that will reduce the co-efficient of friction of the metal axle is the key to axle expandable graphite lubricant. You need to find a product that will bond to the surface of the metal, not just coat it.