I learned to powder coat back in 1986 on an old powder coating unit with square hoppers. Back then we didn’t have any fancy equipment to help us powder coat, much less change colors, so if we wanted to go faster we had to work faster. One of the biggest challenges I faced when I was coating, which still seems to be the challenge of almost every shop I go into today….Color Changes!
There are basically two styles of powder delivery methods for application guns, the Fluidizing Hopper and the Box Feeder, both of these methods work extremely well at delivering powder to the powder gun.
The Fluidizing Hopper is a tried and true method where compressed air is used to suspend powder inside the hopper to be picked up and sent out to the gun. This method allows the powder to be constantly conditioned with clean dry air, which is ideal for powder delivery and application. While the delivery method of powder to the gun is quick and easy, performing a color change with a fluidized hopper is sometimes not so quick and easy as you have to dump any unused powder back into the box and clean out the hopper for the next color. This task usually takes anywhere from 5-15 minutes depending on how large the hopper is and how thoroughly it’s cleaned out.
The other proven method is the Box Feeder. These work very well and allow for fast and easy color changes, however, powder doesn’t always fluidize consistently and evenly over long periods of time. This can be problematic with long runs of powder or in hot/humid areas, and you find yourself constantly kicking the box or running your hand through the powder coating so the gun will spray properly.