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HVLP spray guns give great coverage with minimal overspray. Whether you’re renting a unit for a weekend of spray coating or investing in your own HVLP spray set up, chances are you’ll need to rent or purchase an air compressor, as well. Learn all about air compressor specifications and how to make the right choice to get the most out of your HVLP spray gun.
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Understanding HVLP Spray Gun Compression Requirements
HVLP stands for ‘high volume, low pressure’. The paint exits the spray gun at a lower speed than conventional air guns, so less paint bounces back or off the surface you are trying to coat.
However, HVLP paint guns rely on moving a lot of air through the system in order to get that perfect finish. This means they often require a larger, more powerful compressor than a conventional spray gun, despite operating at lower pressure values.
Key Measurements for Air Compressors
When evaluating air compressors and picking the best match for your spray gun set up, there are three key measurements you need to know.
Tank Size
The easiest measurement to understand on an air compressor is the tank size. Tank size indicates how much pressurized air the air compressor is capable of holding at one time.
Air compressor tank capacity is measured in gallons. Experts at Builder Create share that the smallest compressors hold one gallon of pressurized air, while large, industrial-scale compressors can hold up to 200 gallons.
If you are using an air compressor to power pneumatic tools in your shop, you may find that the tank size is inadequate for spraying with an HVLP gun. Unlike pneumatic tools, which use infrequent bursts of pressurized air, HVLP spray guns use air continuously while spraying. Therefore, the tank capacity needs to be large enough to keep up with your spray.
Pressure
Pounds per square inch (PSI) is a measurement of how much pressure the air in the tank is under. It doesn’t correspond to the pressure of the air/paint spray as it exits the gun – this will be much lower.
Most HVLP spraying is done with a PSI of between 25 and 30. Base coats are usually sprayed toward the bottom of that range, for thicker coverage and less overspray. Clear coat is often sprayed at the top of the range, using a PSI of 29 or 30, for better atomization. The pressure can be regulated on the compressor itself, or a regulator can be attached to the base of the spray gun.
At the absolute minimum, choose an air compressor capable of reaching 40 PSI.
CFM
CFM stands for cubic feet per minute. It indicates how many cubic feet of pressurized air your compressor is capable of generating in 60 seconds.
Two major causes of uneven coverage when using an HVLP sprayer are pressure drop and volume loss. Using an air compressor with a lower CFM than your HVLP spray gun is rated for dramatically increases the likelihood of experiencing pressure drop and volume loss.
CFM requirements vary from one model of HVLP sprayer to another. For instance, a smaller spray gun will use less air per minute than a larger spray gun. To work properly, the CFM rating of your air compressor must be higher than the CFM rating of your HVLP spray gun.
Most HVLP spray guns operate around 10 CFM. A compressor with 12 CFM would be sufficient for guns of this type. Professional level spray guns etups may operate at a higher CFM, be sure to check the manufacturer’s specifications for details.
Tank Size
Tank size is perhaps the most adjustable variable when it comes to air compressors because it is possible to connect one compressor to another tank, increasing the total storage capacity of the line.
If you’re using your HVLP sprayer only for detail work, you can probably get away with a 10 gallon tank. For larger jobs that require more continuous sprayer, 30 gallons is a better size. If you have the space and funds for a 50 or 60 gallon tank, your air compressor will be able to handle any painting task you throw at it.
Conclusion
Using an adequate air compressor is important for getting the smooth, even coverage that HVLP spray guns are known for. Your air compressor must be able to hold at least 10 gallons of air pressurized to 40 PSI. The flow of air must be greater than the air usage of your HVLP sprayer, measured in cubic feet per minute.
