Do I need to maintain 45 to 60% relative humidity for ideal powder coating conditions?
The relative humidity of 45 to 60 percent is important for a few reasons. First, we are creating a corona field of charge around the gun via the electrode on the front of the gun. The moisture in the air is necessary to facilitate the ion bombardment on the particle to be charged. We are ionizing the powder particles and moisture in the air. if the moisture content is too low, the corona filed is not as effective and results in lower transfer efficiency of the application process. Also, if the humidity is too low, there is a tendency for the material to create a tribo charge, which strips away negative ions and leaves the powder with a positive charge. We typically use negative charge for our corona guns. Relative humidity of the environment is important because if it is too humid, the powder will not fluidize as well or will create impact fusion. Too much moisture may seem obvious, but the powder will agglomerate when too moist. Therefore, maintaining 45 to 60 percent relative humidit
