About Air Compressors


An air compressor is the central power source and your major investment. Air compressors are available in horsepowers of 3/4 to 5, or even larger, with a variety of tank sizes up to 80 gallons. The capacity and the frequency and duration of use will determine the horsepower and tank size you'll need for your own projects. A 2hp or smaller will be adequate for most tanks around the house. Typically these size units will have tanks from 7 1/2 to 20 gallons. Choose an air compressor for quality and protective features. Certification by ASME-the American Society of Mechanical Engineers-is the only guarantee of quality in workmanship and materials, and is a main measure of quality. The ASME label will appear on the tank. All compressors do not have ASME certification. Only ASME certified compressors can be sold in some states.

Other features that will be found in a quality compressor include:

An ASME certified safety relief valve which will allow air to escape automatically if pressure in the tank should ever exceed the maximum. This valve will have a pull ring attached to it to allow you to check the valve to make certain the valve is not clogged or corroded.

An oil level sight glass, a tank pressure gauge and, of course, a pressure regulator and gauge are important, as each tool and job has a specific pressure requirement. The tank maintains air at maximum pressure from 100 to 125 pounds of pressure per square inch. PSI is the force of the pressurized air delivered to the tool. Projects and tools have both pressure and volume requirements. Volume is measured in cubic feet per minute (CFM) or standard cubic feet per minute (SCFM). When selecting and using a compressor, it is the relationship of CFM (volume of air) and PSI (force or pressure of air) that is important.

A manual thermal overload button is important in case of overloads or if the motor overheats. If the motor overheats, it automatically shuts off. This protective control button must be pushed for the compressor to run once the motor has cooled down, preventing a sudden and unexpected restart. The best air intake filtration system will be enclosed and mounted on the side of the compressor. This does more to protect the filtering foam, inside the housing, keeping the compressor cleaner, longer.

A belt guard is indispensable protection and the compressor should never be turned on without the guard in place.

A hose rack is desirable for convenience and for protecting the air hose when not in use.

One other feature, most desirable to the do it yourselfer, is a toll free number to call should a question or problem arise.

There are five basic steps in the operation of an air compressor.

  1. Check the oil level to make sure the compressor is properly lubricated.
  2. Plug the unit into the correct grounded, 3-pronged outlet. Turn the pressure switch on and close the tank drain valve.
  3. Adjust the pressure for the tool you will be using and the job you will be doing. Never exceed recommended pressure for the tool or the job.
  4. When finished, shut off the motor, unplug the unit, and turn off the regulator valve. Then bleed the air out of the hose, remove the tool and open the regulator to bleed the air in the tank. If you have a quick connect, you must either remove the hose to bleed off the air from the tank or bleed the air through the drain cocks.
  5. After storing the hose, open the drain cock to release any accumulated moisture. Leave it open until the next time the compressor is used.


Now let's talk about the available tool attachments. If kept properly cleaned and lubricated, air tools are virtually indestructible. With few actual moving parts, maintenance is minimal. They run cool, since their power source is the compressor.

Perhaps two of the most obvious and useful tools are an inflation kit and quick connect couplers. The quick connect couplers make it fast and simple to change tools. The inflation kit attachments allow you to inflate everything from beach balls to automobile tires.

Blo-gun. This attachment is great for blasting away dirt, grease, and dust from hard-to-reach areas. Never point the gun at the eyes or other parts of the body.

Nail gun. Always be sure the gun is flat against the surface being nailed and know what is on the other side, so you won't cause damage or injury with the high pressure of the gun.

 Again, be sure   the stapler is flat against the surface being stapled. Larger Air stapler. Again, be sure the stapler is flat against the surface being stapled. Larger staplers are available for attaching roofing shingles and so forth.

Air sander. The dual-action air sander should always be touching the surface when it is turned on. This type sander is frequently used in automotive work but many other uses around the house, such as rust removal or paint preparation, make it a handy tool to have.

Spray gun. This speeds up paint application and gives a smooth finish. There are a variety of spray gun designs on the market for various types of painting. Many times you can reduce the time required to do a job by 50% or more.

Sandblaster. This works well for removing rust and old paint and for preparing surfaces for painting. This same equipment can be adapted for use with soap and water for pressure cleaning such as degreasing auto engines and lawn and garden equipment.

 This tool takes   the toil out of caulking, by giving a fast, uniform bead. Uni Caulking gun.
This tool takes the toil out of caulking, by giving a fast, uniform bead. Uniform and consistent pressure makes for a stronger bead. This tool can be used for any tube material such as adhesive or grease.

Air ratchet wrench. This is great for tightening bolts, whether building a deck, working on an automobile engine or installing a muffler.

Air hammer/chisel. The masters jobs from masonry to tailpipe removal. It must be up against the surface when started.

Air drill. An air drill makes drilling into any surface an effortless task.

Impact wrench. This is used in automotive and assembly work.

Most air tools are available at hardware stores and home centers. Specialty air tools can be rented. Instructions for each tool attachment are included with the purchase or rental. Read these instructions carefully before attempting to use the tool.