Before you invest in equipment that can be the heart of your operation, you should answer a few questions. Choosing an air compressor for an automotive shop is hard. It especially so, if you are looking at an investment that could amount to thousands of dollars of your hard-earned money.
Tools such as impact wrenches and air ratchets are now common in home automotive shops as well as a necessary part of a commercial shop. In this detailed buyer’s guide, we will look into the best air compressors for Automotive Applications based on air type and size. The Ultimate Question is how large of an air compressor to buy? If you plan on spraying paint or using air tools to do for bodywork, the demands on your air compressor multiply. In this article, we will look at:
- How much-compressed air common air tools need
- The best way to size your compressor
- The specialized air compressor needs of a paint shop.
- The best air compressors for each automotive repair application.
Air Needs for Painting and Body Repair
If your shop does body repair or you want to run a paint gun, or air operated body tools in your home shop, you have an entirely different class of needs for compressed air. Looking back at our chart on air tools and SCFM, you can see that the air needs for a production spray gun may far outrun the capabilities of any small compressor.
Running air sanders, grinders, or production paint guns may see your compressor having to deliver the rated SCFM for the tool on a continuous basis for long periods of time. In this case, the use factor goes out the window, and the total delivery capability of your compressor becomes the controlling factor in your decision on which compressor fits your needs. With air flows, as much as 20 SCFM for some paint application needs, you should consider several options for air compressors that will fill the need.
Rotary Screw Compressors
A rotary screw compressor uses two interlocking parallel rotors running at very high speeds. Because of the high speeds developed, rotary screw compressors typically require more maintenance and are more expensive to operate. The service life on the bearing is usually shorter than those in rotary vane compressors.
Piston Air Compressors
These are the air compressors most common to most people. The principle is well known, and the engineering has been standard on these types of compressors for many years. They work well in shops where air use is intermittent but may not be able to supply enough for painting purposes.
Tank Size Requirements
Thinking about tank size is also important. Industry-wide, recommendations are to allow 4 gallons of tank for each SCFM of air produced by a rotary screw compressor. Piston compressors should be fitted with tanks large enough so that the compressor doesn’t exceed a 50% duty cycle.
Best Air Compressor for Automotive Repair (Based On Application)
These are our choices of the best air compressor in each category for the applications we have discussed.
1. Stealth 1 HP 3 Gallon – Best Air Compressor for Light Automotive Work
The stealth compact 1 HP compressor is mounted with a 3-gallon horizontal tank in a very low-profile configuration that makes it extremely easy to store as well as move about a home shop. This little compressor delivers 2.5 SCFM at 90 PSI. This should be enough for intermittent use of most smaller air tools found in home and hobby shops.
- 65-decibel operation for quiet use around the house
- Oil-free pump requires less maintenance
- Maximum pressure – 150 PSI
- 3.5 SCFM at 40 PSI
- 2.5 SCFM at 90 PSI
- Integral handhold for portability
2. Ingersoll Rand SS5L5 5hp 60-gal Single-Stage Compressor – Best Air Compressor for Auto Repair Shops
Ingersoll Rand is an industry-standard name for automotive shop air compressors. The SSSL5 promises to fulfill the needs of the small to medium-sized automotive shop. The ease of use and low maintenance on these Ingersoll Rand compressors make them ideal for a small shop with a tight budget. The features are what you would expect from an industry leader.
- Cast-iron construction for long life
- 100% duty rated means no one will ever have to wait for compressed air
- Maximum pressure – 135 PSI
- 18.1 SCFM at 90 PSI
- Single-stage compressor for more efficient operation
- 30-amp 230-volt single-phase electric power
- Thermally protected motor
3. HPDMC Rotary Screw Air Compressor with Tank & Refrigerated Dryer – Best Air Compressor for Auto Body Repair Shops
If body and paintwork are the specialties of your shop, you understand the stricter air quality needs when applying automotive paint. The higher SCFM requirements for some paint guns make the need for a high-quality air compressor vital. The HPDMC Rotary Screw Compressor can deliver on those needs. With a built-in refrigerated air dryer, the quality of air at the end of the system is never in question.
Your paint applications will never suffer from air quality issues and you will have all the air and pressure you need to run your other body shop air tools as well.
- 10 HP 230 3 phase electricity required
- 125 PSI maximum working pressure
- 80-gallon tank
- Small footprint requires less shop area
- Spin-on style oil and water separators
- 39 SCFM at 90 PSI
- 80-decibel noise level
- Two-stage rotary compression screw head
- Micro-computer controlled for maximum efficiency
How Much Air Is Needed
There is no exact way to determine how much air you need in your shop. Air tools ratings measure in standard cubic feet of air per minute of use. The problem is that these air tools don’t get used continuously. Air tools, by and large, get intermittent use. You need to judge the use factor of air tools in your shop. Basically, what percentage of the time are air tools in use at any given time in your shop.
Common Tool Comparisons
Let’s look at some of the more common air-driven tools in an automotive shop.
|½ inch impact wrench||5 SCFM|
|3/8-inch air ratchet||3 – 4.5S CFM|
|Air Lift||2 SCFM|
|Tire Changer||1 SCFM|
|Touchup Air Spray Gun||2 – 3 SCFM|
|Production Air Spray Gun||18 SCFM|
|Air Sanders||10 CFM|
None of these tools get continuous use, so the numbers can be deceiving. Industry estimates show that on the average, air tools are only used 15% of the time in an automotive shop. Using this use factor, you can count the tools in your shop, total the SCFM for the tools, and apply the use factor.
For Example, in a shop with three technicians, you find that there are three ½ inch impact wrenches, three 3/8-inch air ratchets, and one airlift. The total SCFM for these tools is about 31 SCFM. Apply the 15% use factor, and you find that you need a compressor capable of delivering about 5 SCFM a minute. We rounded up all the figures to provide a small buffer in the calculations. If you are a home user, the situation is somewhat different. You probably won’t be using your compressor for heavy-duty use and are looking for the most efficient use of space and money when purchasing an air compressor for your home garage.
Sizing your Automotive Air Compressor
For home use, three factors come into play when deciding which air compressor to purchase. You should consider A carefully and judge what compressor best fits your needs based on:
- The largest SCFM usage you can expect
- The highest air pressure you will need
- The usage factor you make of the tools you intend to use
Looking at the average home air compressor can give you an idea of what tools you can reasonably expect to use.
Three Gallon Compressors
|Harbor Freight 3-gallon Pancake Compressor||0.6 SCFM||90 PSI|
|Campbell Hausfeld 3-gallon horizontal air compressor||0.36 SCFM||90 PSI|
|Kobalt 3-gallon single stage horizontal air compressor||2.8 SCFM||90 PSI|
|Stealth 3-gallon air compressor||2.5 SCFM||90 PSI|
With these small 3-gallon air compressors, you will rapidly deplete the air reserve and the compressor will continuously run while you are using the tool. This is hard on the compressor and on the tool.
Opting to size up the tank generally means getting a large compressor pump as well. This also gets you an increase in cost and size. However, you may find that the difference is enough to allow you to use your air tools in your home garage or shop.
|Bostitch 6-gallon pancake air compressor||2.6 SCFM||90 PSI|
|Campbell Hausfeld 6-gallon pancake air compressor||2.4 SCFM||90 PSI|
|Dewalt 6-gallon pancake air compressor||2.6 SCFM||90 PSI|
|Craftsman 6-gallon pancake air compressor||2.6 SCFM||90 PSI|
If you use your air tools in your home garage on an intermittent basis, these 6-gallon pancake-style air compressors should operate your air tool satisfactorily. On tough jobs, you might find that the air compressor must work hard to keep up.
The Decision is Yours
Understanding how to judge the compressed air needs of your shop is a key portion of deciding which type and size of air compressor best fit your needs. A compressor can be a hefty investment and you must make sure that you are making the wisest choices when selecting a compressor. I hope that this article has helped you to make that good decision.