Getting Ready To Spray Paint
The three primary methods of painting are brush, roller, and spray. Of these three methods, spray painting is the fastest. But that's not the only advantage to spray painting. Irregular surfaces are the dickens to cover with an even application of paint—unless you spray paint them.
This article focuses on airless spray painting. The airless spray paint equipment consists of a pumping unit, hose, and gun. A compressor is unnecessary with this system because paint is forced through small tips at high pressure so that a very fine spray is created. The benefits of airless spraying are that there is much less overspray and the air doesn't become heavy with paint mist during use.
The size of the tip and the amount of pressure determines how much paint is delivered. In general, tips are numbered according to thousandths of an inch. For example, a .019 tip is at the larger end of the tip scale and would work well for most latex paints. A .015 tip, on the other hand, would be more appropriate for oil-based paints, varnish, and enamel.
The pressure exerted at the tip is around 3000 psi which means you'll need to be careful to keep your fingers and skin out of range. The spray can cause severe lacerations and may even inject paint into the skin. In the event that paint is injected into your skin, you should seek emergency treatment, since many paints contain toxins which would require treatment by a physician.
To get started, you'll need:
*5 gallon bucket in which you can mix all of your paint. This technique is called "boxing" and ensures that the paint color will be uniform.
*Tape for masking off areas you want to protect from paint
*A disposable mask
*Appropriate clothing—hat, long-sleeved shirt, sunscreen
When you rent or purchase the spray unit, it's a good idea to ask for an extension for the gun. The extension eliminates the need for ladders and aching, overstretched muscles.
Mix the paint in the 5 gallon pail and then either insert the pump's dip tube into the bucket, or fill the unit's hopper. This depends on what type of unit you have. Check that all fittings are locked tight.
Note that there are two control knobs. One controls pressure, the other is a pump/recirculate knob. The recirculation mode keeps paint recirculating through the unit while pumping out trapped air and priming the pump. Set your knob to recirculate and flip the power switch to "on." Let the pump run for a couple of minutes so it will prime and remove any trapped air.
Adjusting the pressure is your next step. Your aim is to create enough pressure for an even spray without "tails" or thick edges to the spray pattern. Decreasing pressure is called "backout." You'll want to backout the pressure knob, and then screw it about 1/3 of the way in. On most sprayers, screwing the knob in increases the pressure.
Aim the gun toward the surface to be painted, or use a piece of cardboard for test painting. Your hand must be in motion as you pull the trigger so that the paint covers a wide area and avoids creating one big wall blotch. If there is a thick edge to the paint fan, screw in the pressure knob 1/4 turn and retest. Repeat until there is no paint tail.