How To Choose An Air Compressor for your Body Shop

When it comes to air compressors, there is no one size fits all solution. Every body shop has different needs and it’s important to find an air compressor that meets your own. This page will help you find the right body shop air compressor for your demands.

Air Compressor FAQ

Q: What size air compressor do I need?
A: Air compressor sizes vary from shop to shop and depend on the types of air tools you’re using, how many air tools you’re using and whether or not you have plans for expansion. Our air tool consumption chart is an excellent resource for determining the best air compressor for air tools in your shop.

Q: How much air pressure do I need?
A: Air pressure is determined by the highest minimum pressure tool requirement. If you have two tools and one has a minimum pressure of 100 PSIG and the other has a minimum pressure of 70 PSIG then the system pressure should be set to stay at or above 100 PSIG.

Q: How do I use compressed air that is stored at a higher pressure for my lower air pressure needs?
A: You install a commercially available pressure regulator that can be set for the required air pressure at the tool.

Q: How can I automatically drain water out of my tank?
A: Install an automatic tank drain that is either float actuated, electronically actuated or timed sequence actuated. Optional no loss drains are available to prevent air loss while the tank is being drained.

Q: How can I keep water out of my distribution lines and tools?
A: There are several things you can do:

1. Install a refrigerated air dryer in line after the compressor unit discharge. The dryer will cool the air to 39 degrees F dew point which means that moisture will not condense as long as the temperatures do not drop below 39 degrees F.
2. Install drop legs in the air service lines to the tool. The tool air line connection should be at least 6 inches above the bottom of the drop leg. Drains should be installed in the drop leg for water evacuation.
3. Make sure that the service piping comes off of the top of the air distribution piping. This will minimize water and debris from getting into the tool.

Q: Why does my compressor run when I am not working or using compressed air?
A: There are a couple of things that could cause this:

1. The compressor may be running to pump the tank up to set the cut out air pressure rating, i.e. 175 PSIG.
2. The compressor controls may be set for continuous run operation where the compressor will unload but not shut down. Change the compressor to pressure switch control for a start stop operation cycle.
3. The pressure switch may be bad and need to be replaced, repaired or adjusted.
4. There may be air system leaks that are creating an artificial demand for air and the air compressor is trying to overcome the air pressure loss caused by leaks.

Q: What are the advantages of using compressed air vs. other power sources?
A: There are many advantages of using compressed air in your body shop:

1. Safety. This is one of the biggest advantages. Electrical shock potential is greatly reduced when you opt for compressed air vs another power source.
2. Ease of use. Typically, pneumatic tools will weigh less than electric tools and make the tools more ergonomically friendly.
3. Mobility. Compressed air has more flexibility than electrical tools because you can opt for a mobile compressor. There are engine driven units and wheeled portables that can be moved around at the jobsite.
4. Versatility. Compressed air can be regulated, which permits varying pressure range uses within one piping system.
5. Cost. In almost all cases, the air tool's initial purchase cost is less than comparable electric or hydraulic tools.
6. Efficiency. Compressed air distribution systems are easier and less costly to install than electrical grids and less demanding than hydraulic system lines. The compressed air system can be modified for multiple points of use much more efficiently.
7. Low maintenance. Air tools have less maintenance and downtime than hydraulic tools do. They also will not burn the air tool motor up like an electric tool could in low electrical voltage situations.
8. Cooler operation. Air tools run cooler because the expanded air dissipates the heat of operation as the air passes through the tool.
9. Reduced risk. Compressed air system leakage will not contaminate a workplace like hydraulic fluid leaks do.

Q: How is compressed air measured?
A: There are four measurement points that are consistently used:

1. Air flow is the measurement of the compressed air that is being supplied to do the work. (ACFM)
2. Discharge pressure is the measurement of the stored energy in the system for use. (PSIG)
3. Temperature is a key measurement because one of the byproducts of air compression is heat. Proper air temperatures are required for the operation of the compressor and the tools that use compressed air as their power source.
4. Moisture content in the compressed air is measured by dew point, the temperature at which water vapor condenses into water droplets. This occurs as air is stored in the tank or in the distribution piping system. Lowering the air temperature prior to system use will provide dry air down to 39 degree F with a refrigerated dryer or -40 degree F with a desiccant dryer.

Q: What does a starter do?
A: The starter is a magnetic device that induces electricity into the motor windings to energize them for work. The starter gets its signal from the pressure switch.

Q: What does a pressure switch do?
A: It measures the cut in and cut out pressure bands for the compressor start and stop settings and either turns the motor on or off as needed.

Q: What does an after cooler do?
A: An after cooler is a device that uses air flow to cool the compressor discharge air temperature prior to being put into the tank for storage. This cooling function will drop out moisture that is in the compressed air. The best practice is to install a moisture separator and trap, in the piping after the after cooler, to collect and drain the moisture before it is carried into the tank.

Q. Which air compressor do I need for painting in a paint booth?
A. When it comes to finding the best air compressor for painting cars, you need to look at a few key factors. Automotive paint guns typically require 90 to 100 cfm in air pressure to operate. Depending on what you’re using the spray gun for (i.e. touch-up, production, undercoat), you may need an air compressor with a higher or lower cfm output. Refer to our air consumption chart for specifics to help you find the best air compressor for your automotive painting needs.

Q: Can I install the compressor unit anywhere in my facility?
A: A reciprocating compressor is a very flexible piece of equipment but some cautions must be taken for an installation site selection. Reference the instruction manual directions that are supplied with each unit:

1. You need a level industrial concrete floor, approx 6" thick, to spot the compressor. Vibration mounting pads are recommended and the units should be installed with double nuts on the bolts. Hand tighten the first nut and then tighten the second nut to keep the first nut from backing off during operation.
2. The compressor should be installed in a well ventilated room with make up air coming from the bottom of the room and the discharge air evacuated at the top of the room. The maximum room temperature for a standard electric motor is 104 degrees F.
3. The compressor must have approximately a 24" clearance from the walls to allow for the designed airflow movement,. This will also allow sufficient room for workmen to do the normal and scheduled maintenance.
4. The discharge line into the air system shall not be smaller than the compressor discharge port size. The best practice is to use flex line connectors when connecting the compressor discharge pipe to the air distribution piping. AT NO TIME SHOULD THE SHIPPING SKID BE USED AS PART OF THE AIR COMPRESSOR MOUNTING BASE.

Q: Can you use the discharge air from this compressor for breathing?
A: NO, THIS IS NOT BREATHABLE AIR QUALITY. BREATHING AIR HAS TO MEET GRADE "D" SPECIFICATIONS TO BE USED FOR ANY BREATHING APPLICATIONS!! Filtration systems are available but it is not recommended that they be used with oil flooded compressors. A recognized certified breathing apparatus should be used for breathing air applications.

Q: What is splash lubrication?
A: This is an engineered design method of lubricating the crank case and cylinder moving parts by using dippers that make contact with the oil surface while the compressor is running. The oil dippers are attached to the bottom of the connecting rods and are contoured to create the most optimal splash patterns for proper lubrication of the moving parts.

Q: What is pressure lubrication?
A: This is an engineered design method of lubricating the crank case and cylinder moving parts. There is a positive displacement oil pump that has a pick up tube to take the oil out of the crank case sump and pressurize it to between 15 and 18 PSIG. This pressurized oil is then forced through orifices that lubricate the main bearings, connecting rod bearings and piston pin wrist bearings. The metered flow not only lubricates those critical parts but it is also more efficient in removing the heat generated by the compression cycle.

Q: Will the body shop air compressor make more air if it is on a larger air storage tank?
A: Definitely not! The larger tank will let you store more air to be a buffer for cyclical uses, especially those that have volatile demand changes.

Q: Can you store more air at higher air pressures?
A: Yes, the higher air pressure will increase the amount of stored air. At 175 PSIG an 80 gallon tank will store 127 cu. ft. of air. The same 80 gallon tank at 100 PSIG will store only 73 cu. ft. of air.

Q: Are there requirements for scheduled maintenance?
A: Yes there are; they are listed in the instruction manual that is shipped with each unit.

Q: How can my mechanics help troubleshoot problems?
A: A complete troubleshooting guide is in the instruction manual that is shipped with each unit.

Q: What is peak horsepower?
A: Peak horsepower is a motor rating used by some small horsepower compressor manufacturers. Essentially, it is the maximum horsepower that the motor can generate and is the point at which the motor is fully loaded and usually causes motor failure. A good rule of thumb for judging the compressor performance is that a true compressor will deliver 3.5 to 4 ACFM per horsepower input.

Q: Can I install this compressor in an outside location?
A: No, this is not recommended. The compressor unit must not come in direct contact with the elements. The best practice is to either put a lean-to over the unit or install it in a small building. If installed under a lean-to, the recommendation is a TEFC motor, NEMA 12 electrical enclosures and, when necessary, cold weather protection for the oil and other lubricants.

Q: Can I use PVC piping for my discharge air piping?
A: No, this is not up to the approved code for compressed air systems. The PVC is an oil based product and it does not react properly to heat, vibrations and oil vapor that are carried in the air compressor discharge air. The PVC is prone to bursting under the normal air pressure and unit operations. The best practice is to use copper or aluminum piping and fittings.

Q: What type of oil should I use in the reciprocating compressor?
A: We recommend using the factory supplied Quincip oil. It is a non-detergent that has been formulated for use in reciprocating compressors. DO NOT USE DETERGENT OILS in the compressor. The detergent oils will foam and cause excessive oil-carryover past the piston rings and will not provide the required lubricity for the moving parts.

Q: Is there an extended warranty program?
A: Please call us for details on compressor warranties as they vary by make and model.