Filtering Compressed Air For Powder Coating - A Complete Guide

When it comes to powder coating there are a variety of key factors that will impact your production and results; from proper surface preparation, to powder coating selection, to powder application, to the quality of compressed air you use for powder coating, each can have a significant impact on the quality of your powder coating work and how much work you can get done in a given time. Given that compressed air for powder coating will have a significant impact on your results, it is important to understand what must be considered when filtering compressed air for powder coating. We will cover the basics of what occurs when air is compressed, the nature of powder coatings, and how to select the right filter for compressed air that will be used for powder coating.

The process of Compressing Air & What Happens when Air is Compressed

Before selecting an air filter for your powder coating compressed air supply, its first important to understand what happens when air is compressed. When air is compressed any water vapor as well as contaminants are essentially multiplied as a compressor takes a certain volume of air and compresses it to fill a smaller space. Contaminant in the air will be intensified while water vapor will also be increased because the air is heated up by the compressor enabling a greater moisture content to be held in the compressed air than was present prior to being compressed. Water and air contaminants can show up in the form of solvent pops, blisters, poor fluidization due to powder clumping together, and a variety of other imperfections in your powder coating finish which is why it is critical to properly filter your compressed air for powder coating.

What to know about Filtering Compressed Air for Powder Coating

So now that you know what happens when air is compressed, you can look at how to filter the air to eliminate the problems mentioned. When it comes to filtering compressed air there are 3 stages that air contaminants can be removed. First is a basic cyclonic separator that spins water and oil out of your compressed air which removes large particles down to .05 microns while a 2 stage system will remove moisture and finer amounts of contaminants down to .01 microns via a coalescent filter. Finally there is a dessicant dryer which is the 3^rd and final stage of compressed air filtration which reduces the temperature of compressed air significantly (to -40 Fahrenheit) which causes water vapor to be removed from the compressed air. For powder coating you typically need your compressed air free of contaminant and water vapor making a 3 stage dessicant dryer the best option, or you can use a refrigerant dryer on your compressor for similar results. One and two stage filtration will not remove water vapor from your compressed air and is generally less than ideal for powder coating compressed air filtration.