Any body shop owner should ask themselves a few basic questions before investing in an air compressor. 

shutterstock_612731900.jpgAn air compressor is an essential tool in a number of industries, from auto manufacturing to woodworking. However, no compressor offers a one-size-fits-all solution. The best choice depends on your line of work, what you’ll use the compressor for, and other specifications.

That’s why body shop owners have their work cut for them when searching for the right compressor. Body shops rely on compressed air for many different tasks, using it to paint cars, inflate tires, and power grinders, nibblers and sanders. Without an optimal compressor on hand, body shops can’t achieve the efficiency and results needed to run a successful business.

Selecting an air compressor isn’t always the easiest decision, but it’s among the most important that a body shop can make. Fortunately, we’re here to help you ask the most important questions and find the best compressor for your business.

How big should my compressor be?

The size of an air compressor can be measured according to the volume of air it consumes in a single minute, a volume usually represented in cubic feet per minute (or CFM). 

The amount of volume needed to perform a single task varies widely, with some common functions requiring as little as 2.5 CFM and others needing as much as 20 CFM. In general, heavy-duty tasks such as painting and sanding require more volume, while lighter tasks such as cleaning and inflating tires require less volume.

How much pressure do I need?

Air compressors are manufactured in a variety of pressures. Select the right pressure range to best support the requirements of the devices you may have in your shop. Most air tools need 90 psi to operate properly. Paint guns may want between 35 psi and 60 psi. Tire machines may need 130 psi. Truck jacks may need 165 psi. Typical maximum operating pressures for body shop air compressors are available in standard pressure settings of 115 pounds per square inch (or psi) or 145 psi or 175 psi. 

Each pressure variation has a “cut-in” pressure where it starts making air, and a “cut-out” pressure where it stops making air. The differential is typically a variance of ~20 psi. Choose the optimum pressure to support the highest level of pressure needed in the shop. 

Note that air compressors produce more cfm at lower pressures and less cfm at higher pressures. So, it makes sense to choose the right pressure for your needs as cfm is what drives your tools. If you have a tire machine that needs 130 psi, for example, while every other air tool needs only 90 psi, you should purchase an air compressor that can pressurize the air to 145 psi or more and use a pressure regulator to feed the air tool at 90 psi.

Where do I plan on keeping my compressor?

Air compressors can be housed in a number of places, but there are some placement restrictions that every user should follow. You want to ensure that the room temperature remains stable as inadequate ventilation will cause the room to overheat and force the compressor to shut down. 

Ideally, you want to maintain about 36 inches of space around a compressor to allow it to breath and, to be able to crouch down to access the components for maintenance. The temperature in the compressor room should remain consistent with the ambient air temperature and ideally stay below 104° F. Any additional limitations specific to your compressor will be included in the user’s manual.

What compressor should I use for painting?

Air compressors are particularly valuable when painting cars. As stated above, having the right air volume (cfm) and pressure (psi) are key in choosing the right air compressor. But discharge air quality is absolutely critical to avoid reworks and to ensure the best possible paint job. Waterborne paints are more sensitive to moisture than solvent based paints. Water in the airlines can mess up your paint job and damage your air tools. Thus, it is critical to ensure that you have the proper air dryer and inline filtration to remove moisture, dirt and oil from the air stream to protect your equipment and finishes. 

Should I buy a rotary vane or rotary screw compressor?

There is something to be said for simplicity and reliability. Rotary vane compressors utilize a single off-set rotor supported by two simple bearings while turning at 1,800 rpm or less, causing several blades (or vanes) to slide in and out of the rotor creating compression pockets. This simple design is engineered for 100,000 hours of service and runs quietly at slow speeds while providing the most cfm for the least amount of energy. 

In contrast, a rotary screw compressor consists of a set of parallel rotors that are supported by 6 bearings. Speed increasing belts or gears turn the screws at high speeds. A heavily insulated cabinet serves to deaden the noise. The bearings have an average service life of 35,000 to 40,000 hours. As a result, a rotary vane compressor is a much more long-lasting and cost-effective investment for any business, and a particularly invaluable addition to a body shop.

While the best air compressor for a given body shop largely depends on the size of the business and the types of vehicles and operations it serves, asking yourself these common questions can make your search much simpler. 

Topics: Rotary Vane Compressor, automotive, paint

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