Mcgraw 21-Gallon air compressor review – Is it worth Buying?

Mcgraw 21-Gallon air compressor review

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Oil-less air compressors are favorite for their maintenance-free service—no oil and periodic maintenance required like an oil-lubricated compressor. 

Loudness 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. Everything you’ll get under 300$. 

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.

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).