Compressed air contain moisture which leads to craters in your paint job and texturing in the finish. These imperfections is easily visible and tell you there is water vapor in the lines. Some use an air compressor like it’s just a piece of equipment to move air.
But air contains particulates, oil mist and water vapor. That moisture will freeze inside lines on cold days, gum up pneumatics and ruin spray gun. It doesn’t take the most expensive equipment to fix this.
Steps to Get Dry Air From Your Compressor
Why Compressed Air Needs Drying
What it takes is some understanding about how compressed air make liquid water. Using the compressor will increase the air temperature inside the tank. As the air cools within the tank, the moisture in the air will turn back into liquid (condensation).
This water will collect on the bottom of the tank and potentially drip down onto your tool or even cause rust on the inside of the tank. This rust will accumulate as sludge which will block your intake valve. To avoid having this bulk water go into your air lines you has to remove it first.
Draining the Air Tank
Most importently, empty out the tank regularly. If you do not use the compressor frequently then empty the tank weekly. Otherwise, open the drain valve located on the bottom of the tank daily.
It’s just an easy task that help prevent rust and clears the intake valve. Once you get water out of the tank, then you have to deal with the water running through your lines. One way around that issue is inline filters.
Inline Oil and Water Separators
An inexpensive accessory called an oil and water separator offer instant relief. It works by spinning the air using centrifugal force. This push the oil mist and any larger water droplet against the sides of the filter.
Water drips into a little cup which you simply have to empty periodicly. While it won’t stop all of the moisture, it will trap bigger particulate. It’s a first line of defense and should protects your gear from quick destruction.
Coalescing Filters for Fine Mist
To achieve this you will need to install a coalescing filter. A coalescing filter employ special media that collects microscopic water particle and oil aerosols. The particles combine with each other to form bigger drops that can be drained off.
These filters is made by companies such as Donaldson or Parker. Coalescing filters are more expensive than a basic separator and their element need periodic changing. But it’s worth it; nothing ruins your car’s finish like a bad paint job.
Coalescing filters capture the finer spray left behind from normal separator.
Using Desiccant Dryers
If even after filtration, the air still contains moisture then you want a desiccant dryer. A desiccant dryer use materials such as silica gel that pull water out of the air.
You see them used in industry a lot and they’re available for those who are serious about needing a dry environment. The drawback to these is that the desiccants gets saturated with water. Either they has to be replaced or regenerated.
Also, they will lower your airflow somewhat. That’s fine though when you require extremely dry air for critical applications. A desiccant dryer act as the last line of defense against humidity.
Choosing the Right Air Lines
The other thing you need to control is your air lines. Use vinyl or polyurethane tubing as they don’t holds moisture like rubber hoses. The inside of a hose can actualy sweat, pulling moisture back in the line.
Vinyl and polyurethane don’t hold moisture and can handles more pressure than low cost rubber. This keeps your air dry from inside the tool to the outside of the system which prevents any further contamination. There is no one product for getting dry air; it’s a system.
It requires proper tubing, coalescing fine mist, filtering bulk water, and draining the tank. It doesn’t take much effort but work every time. Finishes stay perfect.
Tools last longer. When you pick up that spray gun, the air is clean. You would of had to worry about a hidden moisture disaster on your project.
