How To Dry Compressed Air
by Damien Andrews
An air compressor may not be on the top of every do-it-yourselfer's wish list, but in my experience, it's usually pretty darned close. It's little wonder why. Having an air compressor in the shop is a life changing experience. Just imagine being able to check the air in your own tires – not to mention all the marvelous pneumatic tools you'll be able to operate. And let's not forget the blower. I think it would be worth having an air compressor just for its ability to blow focused compressed air for cleaning things. Not just things that are dirty and have hard to reach spots, but things that are being worked on. Nothing cleans out the grain in a fine woodworking project quite like 90 psi from an air compressor. The blower also allows you to force oils into very tight places, spray paint, run a pneumatic grease gun and dry things out and/or off quickly and thoroughly.
Some of the more popular do-it-yourselfer pneumatic tools you can operate when you get an air compressor include:
• Crown stapler aka finishing stapler. This is great for too many things to list, but whenever you need to joins smaller woods together, or install plywood onto a wall, you can't beat a finishing stapler.
• Impact wrench. This is the tool used by garages to remove and reattach lug nuts on wheels. It is the ultimate tool for nuts and bolts. Got a nut that's rusted solid to its bolt? Not if you have an impact wrench. Get the ½" square drive variety.
• Nail gun. Pneumatic nail guns come in a variety of types. Myself, I think the framing nail gun is the first one a new air compressor owner should look into. This tool makes quick work of framing projects such as walls, roofs and decks. It will also save you from tens of thousands of hammer swings – something that is appreciated more and more as the years pass by.
• ½" drive air ratchet. As the name implies, this is a ratchet – with a ½" square drive. You can share ½" drive sockets with the impact wrench. If you find yourself turning lots of nuts and bolts, this tool is hard to beat. It's highly appreciated by do-it-yourselfers who enjoy working on vehicles.
One thing that you don't want to do with any air tool is push water through the air passages and mechanisms. This is most particularly true when you're using an air compressor-powered paint sprayer as the water gets into the paint being applied and really messes things up. But no air tool fairs well with water in the air line. It's both messy and destructive. If you allow water to pass through the air system on some pneumatic tools, the lifespan of the tool can be dramatically shortened. And no matter what the tool, its service life will be reduced.
There are several ways to remove water from your air compressor and its lines. A good start is to drain the air compressor itself, which is almost always accomplished by the use of a small valve located on the underside of the air storage tank. After that, you'll have to create a system which allows for the installation of a water removal device. It can be something simple, like a few feet of iron pipe, or it can be something very ornate and complex. It all depends on your needs, space, and budget. As you'll see, the inescapable budget constraints will largely guide your selection process. But if you're not going to be spray painting a lot of things with your air compressor, you can install a very usable and efficient system for about a C-note. If your do-it-yourself projects call for you to spray paint a great deal, especially with the very costly automotive finishes, then you're best bet is a desiccant-based water removal system. These are excellent systems, but have price tags that rival the cost of even the very largest commercial air compressors they serve. For a quality, desiccant-based water removal system you should expect to pay around $1,500.00. Then you'll have to service and replace desiccant, also.
Referring to Diagram 1, we can see a rather simple, adaptable air system that allows for the addition of an inexpensive (less than $40) water removal device. No measurements are provided because the sizes of the air compressors and shops will vary so much. I helped a pal install a similar system in his garage shop and we ran the pipes all around the corner where the wall met the ceiling. And the schedule 40 PVC is so light that it can actually be installed on the ceiling, if that's where the shop's available space is. In any event, think of Diagram 1 as more of an idea starter than a plan made to be closely followed.
If you want better water removal, and also to remove the particulates in your compressed air, then you'll need to pay out $250-$400 for a filter and water removal device. It would still install as shown in Diagram 1.
I should mention here that if you are adding, or already have, an in-line pneumatic tool oiler, the filter or water removal device needs to be positioned in the line before the oiler.
It's important to note that the pipe carrying the air supply is slanted downwards. This is to encourage and assist condensed water in its gravitationally forced journey. When it reaches the $40 water collection system mentioned above, it falls to the bottom of the usually clear plastic container. When you see water in the container, depress the valve button on the bottom and it empties out the water.
While it's not necessary, I highly recommend installing the optional drain valve shown in Diagram 1. Just extend the pipe down a few inches and then attach the valve. It's easy to reach, and will definitely help reduce the water in your compressed air. When you open the drain valves in your system to allow the water to get out, you don't have to open them very much, or for very long.
You should attach the 1" PVC piping to the wall at intervals. This will prevent the pipes from clattering when pressure builds or releases. I prefer 1" plastic conduit clamps for this job. They're cheap, install easily and hold very well. Use the fewest clamps possible – you can always add clamps later if you find it necessary.
Having an air compressor in the shop is great. It allows the do-it-yourselfer to expand his horizons. An on-site air compressor facilitates the accomplishment of tasks in ways that are impossible without one. Whether or not you install an in-line air dryer, filter or oiler – you're sure to get more jobs done better when you have an air compressor.
TIPS: Only turn your compressor on when you're ready to use it. When you're done using your compressor, turn it off and drain the air and water out using the valve under the air storage tank. Put a few drops of dishwashing liquid in some water and pour it or spray it on new pipe joints to locate air leaks.