The Basics for Choosing the Right Air Compressor

There is a lot of confusion out there about selecting the right size air compressor to run your air tools. Basically, there are several factors to look at when choosing the proper air compressor for your shop or garage.
The first criteria is horse power rating. Most people assume the higher the horsepower rating on the box, the better the air compressor. However, all horse power ratings are not created equal and can easily be misrepresented. What I mean is, you go to your local giant hardware retailer to pick out a new air compressor to run your impact wrench. They have a 5 hp unit that is priced really cheap. Why is that 5 hp industrial unit cost so much more? 5 hp is 5 hp, right? Not necessarily. Let me explain. Look at how much power the hardware store unit draws. It probably needs around 15 amps from a normal 110 volt circuit. At this rating, you are really getting only 2 hp. The 5hp rating on the box is inflated. To really produce true 5 hp you need at least 24 amps from 220 volt circuit to get it. If you are looking for 5 hp electric compressor, buy the industrial unit and stay away from the cheaper unit at your local hardware store. I am not saying that every air compressor at your local hardware is junk. A lot of times one of those units is all you need. Just be aware of the true horsepower rating.
The next consideration when purchasing a new air compressor is, "How much PSI will I need?" For the newbies, PSI is short for "pounds per square inch" and this is how most compressors in the US are rated. In Europe, you will see them measured in bars. PSI is all you need to worry about on this side of the Atlantic. Most of the commonly used air tools require about 90 PSI to operate correctly. However, you will still need a compressor with a higher shut-off pressure. Most air compressors that you find at the local hardware giant are "single-stage" and shut off at 125 - 135 PSI. Don't let that fool you. You might think all you need is 90 psi, so that should work just fine. Generally, these light duty compressors shut off at 100 psi and don't forget about pressure loss in the line. The little light duty compressor will barely run an impact wrench. It might be fine for light duty garage use, but if you really intend use your air tool, more is definitely better. Many industrial compressors are "two-stage," which means they build up to shut-off pressure in two stages. The first stage builds to about 90 PSI and the second stage builds to 175 PSI.
The next rating criteria for air compressors is CFM. CFM stands for "cubic feet per minute". It is a measurement of volume. Basically it is how much air is being moved. Air tools require a certain amount of air volume to run on. PSI is just part of equation. Don't be confused by different CFM ratings at different pressures. Every manufacturer is trying to make their product look better by giving higher CFM ratings at different pressures. The only real concern is how much CFM you will get at 90 PSI. Remember 90 PSI is what most air tools require to operate. To find out what your air tool needs to run, just look on the box for the manufacturer’s specs. Generally, air tools require 4 - 6 CFM. A good rule of thumb on air compressors is you should get 3 -4 CFM per real HP at 90 PSI.
The final factor to consider is tank size. Tank sizes are generally stated in US gallons. For example, 30 gallon is a common tank size. So the question remains, how large a tank do I need? First of all, don't confuse a large tank with more run time for your air tools. If you use your impact intermittently, a large tank is fine. However if you have need for continuous use, you will need a small tank with big enough pump and motor. If the pump and motor are powerful enough, you shouldn't run out of air. You can save some dollars by purchasing an air compressor with a large tank and smaller motor for intermittent use. If you need to run a 1" impact wrench (about 20 CFM) intermittently, and have a small compressor with a large tank, you might have enough air stored in the tank to do the job. However, if you are constantly running your air tool, you will need to invest in a more powerful air compressor to do the job.
You should be able to select the air compressor armed with this information. Basically, you need to decide ultimately what you going to use the unit for and pick the appropriate model.

Air Sanders: Forget electric, go air!

An air sander is a common air tool often overlooked by most people. If you already have an air compressor to run your impact wrench, you may consider purchasing an air sander instead of an electric model. Your average off the shelf electric sander is fine for little home projects. But if you are really concerned about production and speed, an air sander will blow it away. These tools are also more rugged, versatile and lighter. The main reason is the power source is your air compressor, not the little electric motor in the sander. This also makes them easier to fit into weird places and hold over your head to reach a ceiling. At the end of the day, an air sander is much kinder to your hands, while delivering more power. They also come in models that are both sanders and buffers. I really recommend one of these if you are a car or boat enthusiast. An air buffer will make quick work of a long wax job on your favorite ski boat. You can then turn around and use the same tool to sand down your kitchen cabinets for painting. Air sanders are really versatile tools and a great addition to your air tools for your garage compressor. There are also orbital sanders, dual action sanders and palm grip sanders for any application you might run across. It may be time to take a second look at that air compressor stuffed in the garage. They can do a lot more than just fill up tires and run impact wrenches.

The Versatile Reciprocating Saw. The power tool of your dreams.

A reciprocation saw is simply one of the handiest tools you can own. These tools are great for applications in the home or the jobsite. Milwaukee actually invented the first reciprocating saw and is still considered one of the best saws on the market. The Milwaukee Sawzall is the “Zerox” of reciprocating saws. Just go to your local hardware store and ask for a Sawzall, the salesman will know exactly what you need. These versatile tools are fabulous for cutting holes in drywall, plaster, metal pipes and through nails. However, they are not a precision cutting instrument. If you need to cut a piece of molding to fit into a weird place, a jig saw will be better. A great application is demolition for home remodeling. One project I used my reciprocation saw on was removing old siding from my garage. The “recip” was invaluable. I would punch a hole in the wall near the roof, insert the blade and rip down to floor. Nails were no problem, the “sawzall” went through them like butter. The old siding just came right off. Another really great feature of these tools is the ability to quickly switch out the blades. This allows the user to pick the right blade for the right application. You can purchase a demolition blade that is great for rough cutting wood and nails or you can get a blade with fine teeth for cutting metal pipe. You can also get different lengths and sizes. The quick release on the blade is the reason these tools are so versatile. The applications are endless, from landscaping to demolition. If you are considering adding a powertool or giving one as a gift, you can’t go wrong with a good reciprocating saw.