How to Design an Air Compressor System for Paint Spraying

If you work in a paint and body shop, you know that preparation is critical for delivering a flawless paint job. Your air is no different. Taking steps to properly prepare your air can minimize downtime, ensure you get top-notch tool performance, and most importantly, guarantee quality bodywork.

In this guide, we'll cover everything you need to know about prepping your air for bodywork applications and make some product recommendations to get you on your way.

Getting the Most from Your Air Compressor System

An air compressor system benefits your shop in three main ways:

• It enhances the quality of your compressed air.
• It improves productivity.
• It helps maximize your use of shop space.

Productivity

Thanks to piping, an air compressor system allows for multiple line drops that can service different workstations in your shop simultaneously. For example, while one technician uses an impact wrench to remove wheel lug nuts to prep a car for painting, another can strip paint on a different car with a sandblaster. You're able to run multiple workstations at once and get more work done in less time, which means more money.

Air Quality

Besides the air compressor and piping, a system includes a dryer and various filters that optimize the air for your application. Just like you would prep the surface before a paint job, you need to prep the air that will be sprayed on it. You can't allow any moisture or oil into the paint. Having the right desiccant dryer and filters will remove these contaminants and provide clean, dry, compressed air. Consistent air pressure is also vital for maintaining a consistent spray pattern and application, and a pressure regulator installed near the point of use will accomplish this.

Space

A well-designed air compressor system increases organization and makes it easier for technicians to access and use their air tools. For example, you can install hose reels in your ceiling and connect them to your system to free up floor space. You can permanently install an air compressor in an unobtrusive location and run neat lines to all your workstations.

Air Compressor System Components

Now, let's get into the specifics of the components you need in your air compressor system. First, it's worth noting that there is no one-size-fits-all solution. Every shop is different. The number and type of components you end up needing will vary based on your shop size, environment, applications, and other factors.

In general, though, an air compressor system is comprised of the following:

• Air compressor
• Air filters
• Dryer
• Pressure regulator
• Lubricator
• Piping air delivery system

Let's go into each component in more detail.

Air Compressor

Unless you're switching to an air system for the first time, you're probably familiar with the role of an air compressor. It's the heart of the system that supplies compressed air to your tools. 

For professional body shops, two-stage reciprocating and rotary screw air compressors are the best option due to their higher volume and pressure outputs. Higher air volume can meet the needs of multiple workstations, while higher pressures can handle a wider range of tools.

Most body shops run their air tools intermittently throughout the workday. A two-stage air compressor is well-suited for handling this type of intermittent use. Body shops with continuous operations would likely opt for a rotary screw compressor, which is designed to run nonstop.

Those choosing a two-stage air compressor should find one that includes a built-in automatic drain valve and aftercooler. Here's why.

With normal use, water will collect inside the air compressor's tank. This water, called condensate, needs to be drained regularly, or it could reduce air storage volume, cause corrosion and damage to the compressor and tools, or contaminate your paint job.

Note: Condensate can contain oil, dirt, and other contaminants that can damage sewage systems and the environment if left untreated. Many areas also have rules and regulations regarding proper disposal. We recommend using a condensate filter for every application, but make sure you understand and follow local laws.

An aftercooler is the first step to cooling and drying the air to prepare it for applications like painting, where excess heat and moisture can damage the quality of your work.

Most important of all, when selecting an air compressor, is ensuring it can handle your shop's CFM and PSI requirements. When calculating this, consider all the air tools your shop will be running simultaneously. Feel free to contact us for help sizing your air compressor.

The Best Air Compressor for Spray Painting: EMAX ESP10V120V1 

The EMAX ESP10V120V1 two-stage air compressor is loaded with all the features needed for most body shop spray applications. Regarding space, its vertical, 120-gallon tank leaves a small footprint in crowded shops. Plus, its patented Silent Air Technology reduces sound levels by up to 35%, minimizing extra noise. 

Regarding power, the 10-horsepower motor drives the pump to deliver 38 CFM at 100 PSI, which is great for intermittent applications. It will run continuously during business hours without skipping a beat. The low, 1750 RPM motor minimizes heat, thereby reducing wear and tear for greater longevity. A built-in magnetic starter provides extra motor protection and trouble-free operation. 

The enemy of any spray-painting application is moisture. If it gets into the paint, it can botch the whole job, leaving fisheyes and unsatisfied customers. Thankfully, the EMAX reduces moisture through its intercooler and aftercooler, which work to cool the air between and after compression stages. Cooling the air helps to remove excess moisture in the form of condensation. An electronic drain valve automatically removes this condensate from the air system, saving time and money on maintenance. 

In addition, the EMAX has a raised pump mounting platform that allows for a constant flow of cool air from the flywheel fan around the pump crankcase, ensuring cooler pump oil temperatures and keeping heat off the pistons and connecting rods. According to EMAX, this Air Stream technology lowers operating temperature by 35%, which prevents moisture from entering the oil and improves pump life. 

The pump has a belt tension adjuster that reduces vibration and extends belt life. It is also protected by 5-layer filtration. Overall, the pump is rated at up to 70,000 hours of use, ensuring it will power the shop for years to come. 

The EMAX ESP10V120V1 is recommended for any professional auto shop with tool needs of less than 38 CFM (ensure the shop is set up for the required single-phase 208-230 volt operation). An extended 5-year warranty on the compressor and an extended limited lifetime warranty on the pressure-lubricated pump are available. It offers a rare combination of power, efficiency, and value that will be a major asset to any business.

Air Compressor Filter System 

Air filters protect the air system by removing dust, oil, water, and other contaminants that could damage the air tools in the system and compromise the quality of paint jobs. 

There are three main types of air compressor line filters used in automotive shops: 

• Water Separators remove the largest water particles from the air, typically down to 10 microns. Moisture removal is extremely important in ensuring air quality for the end use, especially when painting. The water separator is the first of several components that help dry the air. 
• General-purpose filters remove particulates between one and five microns in size, typically water, oil, and dirt. They are the first line of defense and sometimes the only filter necessary for use with air tools like impact wrenches, sanders, and grinders. General-purpose filters can be purchased as standalone components or as part of a dryer. 
• High-efficiency filters remove particulates as small as 0.01 microns and handle everything a general-purpose filter does, plus more. These are essential for applications where any remaining oil or dirt could ruin a paint job. 

Your shop environment is key to knowing the types and number of filters you'll need. For example, if you're in a humid area and the garage is open all day, you'll be dealing with extra moisture in the air that must be filtered out. If your shop is extra dusty or you share air with a space where sandblasting takes place, you'll need to invest in an extra dust filter, in addition to the other filters.

Best Water Separator for Air Compressor: Tsunami 21999-0131

The Tsunami 21999-0131 water separator is recommended to effectively remove large water particles from the air supply. It can handle up to one quart of water per minute and filters particles down to 10 microns, prepping the air for finer downstream filters. 

The Tsunami easily connects with a 1/2" NPT inlet and outlet and can handle up to 50 CFM of airflow, air pressures up to 250 PSI, and temperatures up to 175° F. 

Users can count on long life, minimal maintenance, and ease of service. The Tsunami includes an integrated float-type drain with an elevated sump to allow sediment to accumulate. The filter head is machined from 6061 Aircraft-Grade Aluminum and anodized inside and out to provide maximum protection against corrosion and trapped contaminants. 

NOTE: This unit comes built-in when purchasing the Tsunami Pro-10 Series desiccant air dryer (discussed below). 

Best High-Efficiency Air Compressor Filter: Tsunami 21999-0131-Z-FD

To remove the tiniest particles from the air, incorporating the 50 CFM Tsunami 21999-0131-Z-FD high-efficiency oil coalescing filter into the system is recommended. It filters out oil aerosols down to .001 ppm and particulates down to .01 microns. 

A 1/2" NPT inlet and outlet make this filter compatible with most air systems, and the bottom cap and integral automatic float drain are easy to service, making maintenance a breeze. 

This filter is built to last, featuring a durable aircraft aluminum head and the ability to handle large surges of water from the air. The removed liquid drips into an elevated sump and is automatically ejected by the float drain. After installing the Tsunami, clean air will quickly be taken for granted. 

NOTE: This unit comes built-in when purchasing the Tsunami Pro-10 Series desiccant air dryer (discussed below). 

Air Compressor Dryer System 

The dryer is a critical component in any professional air compressor system. It removes moisture and lowers the dew point of the compressed air. Removing this moisture is critical to protect the air system components, tools, and end products. 

Unlike the filters discussed above that only remove larger water particles, a dryer essentially squeezes out all the moisture that filters can't. 

Desiccant Dryers 

For bodyshop applications, you should invest in a desiccant dryer, which traps water in a desiccant material like silica gel or molecular sieve media.  

Desiccant dryers trap moisture using a process called adsorption. Through adsorption, the water particles stick to the surface of the desiccant material. This is different from absorption, where a substance is taken up by and distributed throughout another substance. 

Properly sized and installed desiccant dryers remove virtually all moisture and can deliver air with a dew point as low as -40°F.  

NOTE: Always install an oil filter before the desiccant dryer to prevent oil from damaging the desiccant material. The desiccant material needs to be regularly regenerated or replaced to maintain proper performance.  

Membrane Dryers 

Membrane dryers are a cost-effective option for applications with lower airflow needs, typically less than 20 CFM. Like desiccant dyers, they are capable of delivering air with a dew point as low as -40°F. 

Membrane dryers use a membrane that allows water to pass through more quickly than other gases. This removes the moisture while allowing the remaining air to pass.  

Best Air Dryer for Air Compressor: Tsunami Pure-10 21999-1010 

The Tsunami Pro-10 Series regenerative desiccant air dryer is a premier choice for sensitive painting and bodywork jobs, thanks to its multi-stage filtration. Able to handle 40 CFM of airflow, the Tsunami delivers very dry, clean air down to an -80° F dew point and runs on 115-volt or 120-volt, single-phase power. 

An automatic drain valve removes condensate. The dryer features a 1/2" inlet, has a maximum inlet pressure of 175 PSI, and can handle incoming air up to 150° F. 

To protect the desiccant material, Tsunami features two stages of filtration before the drying stage. During the first stage, a water separator removes water and particulates down to 10 microns. Then, in the second stage, a high-efficiency oil coalescing filter removes oil aerosols down to .001 ppm and traps particulates down to .01 microns. 

Finally, the regenerative dryer performs its function. There are two towers filled with desiccant material for redundancy. When one tower gets saturated with moisture, the dryer will automatically redirect the compressed air to the other desiccant tower, allowing the first to regenerate. 

Finding a better desiccant dryer is difficult. It checks all the boxes for pre-filtration and drying capacity, ensuring that paint jobs have the cleanest, driest air possible. 

Condensate Filter 

Air treatment systems produce condensate, which needs to drain into the sewage system. However, most localities prohibit oil-contaminated water from entering the sewage system to protect the environment. 

An oil and water separator passes the condensate through a series of filters that separate and capture the oil, allowing the remaining liquid to enter the sewage system safely. 

Pressure Regulator 

Air tools, especially paint guns, need air at a specific, consistent pressure to perform at their best. A high-quality pressure regulator installed near the point of use is critical for delivering accurate and consistent pressure to the tools. 

Installing a pressure regulator at each outlet is recommended. This allows operators to fine-tune the pressure for each tool being used and, by being close to the tool, avoids pressure losses associated with long tubing and piping. 

Many pressure regulators come with a built-in filter, providing extra filtration before the air is used. Pressure gauges come standard on most regulators, but not all. Selecting a regulator with a gauge is highly recommended to avoid the need to purchase a separate gauge. 

H3: Lubricator 

An oil lubricator is recommended for any air compressor system feeding automotive repair tools, such as impact wrenches, air hammers, ratchets, etc. By adding oil to the compressed air, the lubricator helps maintain tool performance. The lubricator should be installed at the point of use—right before the mechanical air tool itself. 

NOTE: A lubricator should never be used on an air line supplying a paint sprayer, as this will undoubtedly ruin the paint job. Separate hoses should also be used for lubricated and non-lubricated tools. 

Best Air Compressor System Lubricator: Campbell Hausfeld PA211400AV 

The Campbell Hausfeld PA211400AV conveniently combines a lubricator, filter, and pressure regulator into one compact unit. 

A general-purpose 5-micron filter provides drier, cleaner air to your tools. Meanwhile, the built-in pressure regulator can be adjusted from 0 to 215 PSI to handle a wide variety of tools and equipment, up to 75 CFM, with a 1/2-inch NPT inlet and outlet. Most importantly, the lubricator adds an adjustable amount of oil into the air stream to keep your tools running smoothly. It has a holding capacity of 4.2 fluid ounces. 

Piping System 

Pipes are the arteries of an air compressor system. They carry the compressed air from the compressor, through all the filtering and drying components, into air tools and paint guns. 

There are several piping options: 

• Black iron pipe is very durable but prone to rust and corrosion. Rust particles from the pipe could break off and enter the air, damaging tools and paint jobs. 
• Copper piping is corrosion-resistant but is heavy and requires more installation skill in soldering the joints. 
• Aluminum piping is lightweight, corrosion-resistant, and handles heat well. 
• Flexible aluminum piping has the same benefits as rigid aluminum but is easier to install thanks to its push-to-connect technology. 

Do not use PVC pipe in the system as it is not designed to withstand the pressure or heat present in air systems. This could cause the PVC to fail and explode. Likewise, avoid galvanized steel piping. The coating is prone to flaking off and damaging tools and paint jobs. Using non-rated piping is an OSHA violation and could expose the shop to civil and criminal penalties. 

Sizing the pipe properly is also extremely important to avoid pressure losses and wasted resources. Proper sizing takes into account flow rates, pressure drops, and other variables. As a rule of thumb, ensure the pipe diameter matches the air compressor outlet to prevent flow restrictions. 

Hose Reel 

A hose reel is recommended for any automotive and body shop. It is an efficient and effective way to get air where it is needed without cluttering the shop. 

Best Air Hose Reel: DeWalt DXCM024-0344 

The DeWalt open double-arm air hose reel is a top-tier choice. 

It includes a 50-foot premium nitrile rubber hose that can sustain temperatures of -40° F to 150° F and is resistant to twisting or kinking. The frame's all-steel construction can withstand rough shop conditions, and a self-leveling system winds the hose evenly and smoothly every time. The 1/2" NPT connection accommodates a wide range of air accessories and tools. 

A standout feature is its mounting flexibility. It can be installed on the floor, ceiling, or wall. Ceiling installation is highly recommended wherever possible; shop owners often do this to simply pull down the air hose when needed. This saves floor space and reduces tripping hazards. Plus, the entire hose reel weighs only 43.4 lbs. for simple handling. It makes work easier and is a valuable addition to the shop. 

End of the Line 

Finally, the system yields dry, compressed air ready to go into the air tool. For body shops, this means spray guns. Designing a proper air compressor system is hard work upfront, but it prepares the air for a quality paint job each time the trigger is pulled. 

Appendix A: Compressed Air Pipe Sizing Table