What is a compressor like to use?

I have included this page for people who are thinking of buying a compressor and have yet to work with one. That was me when I was looking for a compressor!

Imagine we are starting a day of work.

When you switch on a compressor it starts thundering away and that thunder gets stronger as the tank charges towards its highest pressure. The dial of the air pressure gauge will be climbing steadily, though will stop moving when the pressure in the tank exceeds the pressure set on the reducing valve. When the compressor reaches it set upper pressure, probably 150 p.s.i., which will take about two or three minutes, a pressure-operated electrical switch switches off the motor, with a click and a very short harsh hiss. All should be quiet then. So the compressor is still "switched on" but it is doing nothing.

If nothing is connected up, I would bring my air tools and my reel of air hose. I press one end of the hose into the quick connector on the compressor's reducing valve. There will be a quick hiss from a fraction of leakage, and a whistle from the reducing valve as the hose pressurises up to the set pressure. I reel out the hose to the place I want to work and am ready to plug whatever tool I want to into the free end of the hose, with its quick connector.

Let's say I start work, fetching an incomplete piece of work from the store. I might blow it clean with an air blower. So I select the air blower, plug it into the air hose, probably with nothing more than a firm click. When I point it at the work and press the trigger, there is a harsh hiss and a roar and cobwebs and dust are gone - so gone.

I want to dress down a new area to weld. I unplug the air blower, pushing it inwards against air pressure and pulling the release collar back, so releasing the blower. There will be just a very short "chunk" sound as the valve closes the free end of the hose.

Let's say I dropped three drops of oil into the angle grinder when I finished work last time. So no need for more oil. So plug the angle grinder into the quick connector.

Bring the angle grinder to the work, move your finger to swing the safety lock out of the way then squeeze on the air valve and touch down on the work. The sound is a whirr and a gentle hissing. Nothing loud this time. There is a "ringing" from the grinding, but this is the main noise and not loud with a 4inch grinder. Release the air valve and the grinder stops. The safety toggle means it is safe to set down the grinder still connected to the air hose, even though the trigger action is delicate.

So far the compressor has not done anything. The air is being drawn on the receiver's air storage. However, working away, the pressure drops below a predetermined pressure which might be 120 p.s.i. and the pressure switch turns on the power to the compressor motor, setting the compressor going again and again the compressor is thundering away.

With not grinding continuously, the compressor soon catches up and with another harsh short hiss the pressure valve switches off the compressor.

And that's pretty much how it goes on, selecting and changing tools, doing work and the compressor starting and stopping.

Happy work!

(Richard Smith, June 2005)