Air Compressor Selection
Air compressors are available in a variety of models and sizes. Portables type compressors can be carried by hand to different locations. Large compressors are permanently located and the air must be conducted through pipes or long hoses. In most cases, the larger the physical size of the air compressor the more volume of air can be used at any given time.
The Overall Consumption
Air compressors are rated in CFM, cubic feet per minute. The pressure is also denoted in the air compressor specifications. The typical pressure for an air compressor is in the area of 120 pounds per square inch (PSI). The volume of air, CFM, is the most critical when choosing a compressor. Air powered devices, such as paint sprayers, sand blasters and other tools, are rated by CFM and pressure. These consumption rates are given in the tool's manufacturers specifications. Different tools will have various air consumption rates. When looking for an air compressor, it will be a wise choice to pick a unit that will satisfy all of the air devices needs.
Storage Tanks
Most all air compressors come with some type of air receiver or storage tank. This tank holds in reserve compressed air to be used at any given time. The more consumption an air tool has, the more of a reserve the air compressor may require. Certain HVLP (high volume low velocity) paint sprayers and sand blast units will require large volumes of air. The compressor must be matched to the storage tank. If the compressor is too small, the electric motor that powers the air compressor will constantly run and may prematurely fail from over use.
Match the Tools
By finding the largest air tool consumption you can properly match an air compressor to those specifications. In other words, if a paint sprayer unit consumes 10 CFM to 15 CFM you will want to look at a compressor that can match or exceed those specifications. Even with a large storage tank the compressor will have to replace that air once the pressure drops below a specified point. In most cases though; a single-phase air compressor, one that plugs into the wall outlet, that is in the 5 horsepower range with a 25 gallon to 30-gallon storage tank may suffice for most paint gun applications. It is recommend to check the individual specifications and cross check those with the air tools that are going to be used.
Other Items
All air compressors should come equipped with an on board air pressure regulator. This regulator must be adjustable to a low range of at least 10 PSI, and up to the maximum allowed pressure created by the air compressor. When using an air paint sprayer, the air must be completely dry. You will want to add an inline air dryer. The air dryer will remove the moisture from the compressed air. All air compressors will take in atmospheric moisture and conduct water through the airlines. Water in the paint sprayer can contaminate the paint and ruin any paint job on a car. Use only high quality air hoses, be cautious of cheap plastic coiled airlines for the main air hose. While the small plastic airlines are fine for short runs, the thin plastic line will soon develop small holes and pressure will be lost.
