If you purchase a "do-it-yourself" type air compressor, or if you purchase any type of air compressor for that matter, check to make sure that it comes with an Air Regulator. If not, purchase one. You will be glad you did!

An air regulator is a device that lowers the downstream air pressure. Downstream air is the air that's moving from the regulator towards your application.

Compressed air will flow from the compressor reservoir into the air regulator (this supply is called upstream air) and through a system of an internal diaphragm and springs, the regulator will maintain a constant downstream air pressure level, despite changes in the upstream supply pressure from the tank.

Recognize that you can only use a compressed air regulator to increase the downstream air pressure up to the level of the upstream supply air pressure. An air regulator will not enable you to "dial up" the downstream air pressure higher than the upstream level.

However, if you can figure out how to do that, do let me know, and we'll both get rich! ;-}

You will want to set the downstream air pressure from your regulator at a pressure level that is below the lowest air pressure that will be incoming from your air compressor. Here's why.

The compressor maximum pressure set point is the pressure level inside the compressor receiver at which the compressor shuts itself off. This is also known as the "cut out" pressure.

When the cut out pressure is reached, the compressor stops compressing air. When you start to use compressed air from the compressor tank, the pressure inside starts to drop, and eventually the compressor will start again. This is the "cut in" pressure point.

As a result, your application, be it an air tool or an air brush, will "see" varying pressures from the tank as the compressor cycles on and off between the two set points.

For most applications, a varying air pressure supply isn't satisfactory and it is particularly problematical for folks that use compressed air to spray paint. Despite your best efforts with the air brush, if the supply air pressure is constantly changing, so too will the quality of your work.

This brings us back to the why you will always want to have an air regulator installed in the line between the compressor and your application.

If you set the downstream air pressure at a pressure level BELOW the cut in pressure level of the air compressor, in theory, the air pressure to your application should never change. As the air compressor goes through its normal cut-in and cut-out cycle your air regulator ensures that your downstream device will see a steady, non-fluctuating, supply of compressed air.

This is theoretical only, unfortunately. If your application consumes more compressed air than your compressor can generate, even though you have set your air regulator at a "safe" level, eventually the air pressure from the tank will fall below the level your regulator is set for, and the downstream device will see a steadily diminishing air pressure supply too; this even though your compressor may have cut-in, and is trying desperately to build up a supply of compressed air inside the tank.

This is why you really want to know how much air you need for your application to ensure that your air compressor has enough capacity to oversupply your needs. Check out details of this at ABOUT-air-compressors. com!

Know that air pressure regulators come with different levels of accuracy with the least accurate being, as you might guess, the least expensive.

Most general purpose compressed air regulators will have an accuracy of 3-5 PSI, meaning that the actual air pressure that your device is being supplied through the regulator will vary within that range, despite what it says on the gauge.

If you need more accuracy, opt for a precision regulator, and depending on the manufacturer, you may be able to get a downstream air pressure within a .5 PSI accuracy of the pressure reading on the gauge.

General purpose air pressure regulators normally have an operating range in the area of of 0 - 120 PSI. Others will be rated for pressures of 0-100 or 0-150 PSI.

You can also get air regulators with a narrower and more specialty oriented range of pressures such as: 0-10 PSI, 0-20, 20-60 PSI and so on. At the other end of the scale, you can purchase regulators that can safely handle many thousands of PSI.

For most do-it-yourself types, a general compressed air regulator with a range of 0-100 PSI will do just fine.