Mcgraw 21-Gallon air compressor review

Mcgraw 21-Gallon air compressor review | Is it powerful enough?

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Oil-less air compressors are favorite for their maintenance-free service—They don’t require periodic maintenance.

Loud running noise is the major issue for a larger oil-free compressor (above 80DBA). On the other hand, the quietest versions require extensive costs.

If you need an air compressor to upgrade older oil-version or need a new compressor for your home garage, the Mcgraw 21-Gallon air compressor could be the best bet. It offers all the features: decent airflow, lower noise level, easy move capability, adequate tank pressure, and faster recovery.

Mcgraw 21-Gallon air compressor Specs

  • Oil-free pump: Does not require any periodic maintenance
  • 21-gallon larger tank for the long-time run
  • 175 PSI maximum tank pressure 
  • 4 SCFM of airflow capacity at 90PSI
  •  1.6 HP motor with thermal protection
  • Ergonomic handle style and larger wheels for smooth portability
  • Require 7 minutes and 30 seconds to fill the tank at maximum form ZERO
  • 1 minute and 56 seconds need to recover the tank pressure from 135 to 175 PSI

What can you do with the harbor freight Mcgraw 21-Gallon air compressor? 

This 21-gallon compressor is an ideal choice for car owners, DIYers, and home garages using purpose. 

We tested this harbor freight Mcgraw 21-Gallon using the most common garage air tools, like impact wrenches, cut-off tools, air drills, Die grinders, and air chisels. 

Here’s the table of how long these tools ran before the tank pressure reached under 100PSI.

Here’s a table about how long the compressor can run air tools before the tank pressure falls under 100 PSI.

Air toolsRun time (175-100 PSI)
Blow Gun1 minute and 10 seconds
1/2 Inch Impact wrench50 Seconds
Air Drill54 Seconds
Cut-Off tool53 Seconds
Die Grinder56 Seconds
Air Hammer (Chisel)55 Seconds

Can you use the Mcgraw 21-Gallon air compressor for auto painting? 

The tank pressure, pressure recovery time, and airflow capability allow this Mcgraw compressor for moderate auto painting jobs. 

Mostly standard HVLP professional paint sprayers require a minimum of 10 to 20 CFM of air at 20 to 40 PSI. But, in this case, this Mcgraw 21-Gallon compressor does not fit professional painting jobs. 

I used it in my garage for occasional auto painting. Yes, it holds up all time. This 21-gallon compressor works perfectly in moderate use. 

Once the tank pressure is filled maximum of 175PSI, you can run the paint sprayer at full throttle for a whole minute before the motor kicks on. Even I haven’t faced any power-dropping issues in the paint gun when it recovers the tank pressure. 

Note: When I was using this 21-gallon compressor continuously for a long session, the compressor kept running. You know that oil-less compressors are unable to run continuously, which causes several damages in the future. 

Can this harbor freight Mcgraw 21-Gallon compressor run high-demanding air tools? 

It depends on an air compressor’s airflow capacity and tank air-storing capability. 

High-demanding air tools like impact wrenches, cut-off tools, die grinders, air drills, air hammers, etc. These kinds of air tools require a minimum airflow of 10 CFM at 90 to 120PSI. 

So, if you look at the airflow rates of the Mcgraw 21-Gallon compressor, it’s sheer; it only holds you on for a few seconds, not continuously. The airflow capacity of this compressor is the same as the Mcgraw 20-gallon oil-lubed version. But the maximum tank pressure of the 21-gallon is higher than the 20-gallon, which is 175PSI. It’s an advantage over the 20-gallon version. 

Impact wrench Performance Test: 

We used a 1/2-inch Ingersoll Rand air impact wrench to ensure how long the compressor could hold an air impact wrench. Our impact wrench air requirement was 15 cubic feet per minute at 90 PSI. We ran the impact wrench at full throttle, and in 27 seconds, the compressor kicked on. After all, we got 53 seconds of run time before the tank pressure reached 100PSI. 

So, you will get 50 seconds of optimal performance from a 1/2-inch impact wrench using the 21-gallon Mcgraw compressor

You must remember you won’t get optimal performance from high-air consuming air tools when the compressor keeps running to recover the tank pressure, as its air-delivering capacity doesn’t meet your requirements (4SCFM). 

Testimonials: Hear What the long time users Have to Say about the 21-gallon Mcgraw air compressor

Best for framing

I mainly purchased this 20-gallon mcgraw air compressor specifically for the purpose of operating my framing gun. To my pleasant surprise, it utilizes a lower amount of amperage compared to my smaller, oil-less compressor. This is particularly noteworthy because the electrical system in the location where I work only supports 10-amp breakers. Despite this limitation, the compressor performs exceptionally well, effortlessly keeping up with the demands of rapid-fire nailing. It eliminates any downtime that would typically be spent waiting for the air pressure to build up before resuming work.

The best compressor at great value

I have owned this air compressor for quite some time, and I am pleased to say that I have encountered no issues with it. When it comes to providing a sufficient amount of air for air tools, it performs admirably without any problems. One of its notable features is its portability, allowing me to conveniently use it for tasks such as inflating tires in my driveway. As I move the compressor around, I have not experienced any difficulties with the front drain valve hitting objects or hindering its mobility.

Moreover, I have found that this compressor fits perfectly in the corner of my shed, maximizing space efficiency. Even in cold weather conditions, I have not faced any problems with starting it up. To ensure optimal performance, I make it a habit to keep the drain open after each use and close it during start-up. With my extensive experience as a mechanic spanning over 40 years, I heavily rely on various air tools. This particular compressor has truly met my expectations, eliminating the need to halt operations and wait for the compressor to recover.

Furthermore, this compressor offers excellent value for the price. It comes equipped with built-in regulators and an oil sump, and despite its functionality, it is not excessively heavy, making it manageable to transport when needed. Overall, I am highly satisfied with this air compressor’s performance, durability, and features, which have greatly facilitated my work as a mechanic.

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Hi, Eddie T. Jones and I am the author of I have been working with household appliances, tools, outdoor gear, and gardening tools for several years. I publish unbiased comparisons based on user reviews, expert reviews, and test results. I hope you like the website.

Best regards, Eddie T. Jones

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