The cost of powder—critical to the success of powder coating applications — is a function of two variables. One, of course, is the manufacturer’s price for the powder. The other is the powder’s coverage. A powder’s coverage depends on the specific gravity of the powder, the transfer efficiency of the process, and on the required coating thickness. Transfer efficiency is expressed as the amount of powder sprayed divided by the amount that adheres to the part. Some major factors entering into transfer efficiency include: charging capability; the amount of powder exiting the gun; grounding of the part; the kilovolts of the corona field through which the powder passes before landing on the part, and the distance the operator holds the gun from the part. Powder prices vary depending on specific formulations, performance properties and manufacturers. Prior to selecting the powder to purchase for a specific application, the end user must: clearly identify the performance properties required for the application; determine the powders meeting those requirements, and compile a list of manufacturers providing these powders (and at what cost).
By Gary Conner
By George N Bullen FSME