Spray painting with water-based paints gives a smooth, even, professional finish to any surface. If you paint more than once or twice a year, you should think about getting a spray painter for your jobs. Buying spray paint equipment takes a little thought. Decide how much painting you plan to do, as well as the viscosity of the paint you will most often use. Viscosity refers to the paint's resistance to flow, or how thick the paint is. If you plan on using thick paint, you will need more power in your paint sprayer than you will need when using thinner paint.
Electric Cup Gun
These are self contained, hand-held units that do not have a lot of power and therefore are not good for big jobs. A small bottle-shaped container, called a cup, is filled with paint and screwed into the sprayer. The sprayer is made of plastic and looks like a toy water gun with a large bottle hanging down. The sprayer forces air into the bottle creating pressure that pushes the paint and mixed air up a tube and out of the spray nozzle. This type of sprayer is good for thinner types of water-based paints. These sprayers tend to be noisy and are not good for large jobs. In general this type of sprayer is for the hobbyist or for small painting jobs.
Compressed Air Sprayer
These units follow the same design as the electric cup gun, but have more power and are made of metal instead of plastic. Instead of an electric cord, an air hose attaches to the spray gun from an air compressor, which pressurises the paint in the cup in order to spray the paint out of the nozzle.
This method allows you to adjust the air pressure going into the paint cup, which helps to adjust the amount of paint being sprayed. Using a larger compressed air tank allows you longer spray times, as well as a continual supply of air. However, it is a lot less portable than an electric cup gun, depending on the size of the compressor you use.
A compressed air sprayer will give you a more professional job, and the ability to use a variety of different spray nozzles tailored to the individual job. Because of the high volume of paint and air that travels through this type of sprayer, water builds up in the tank and lines from the compressed air. You need to check on the water in the bottom of the tank and water in the lines in order to avoid water blotches on your painted surfaces.
There are two different types of airless sprayers, membrane or diaphragm pumps and piston pumps. Unlike air sprayers, airless sprayers work by pure brute force without mixing air into the paint, and are put in the professional class of paint sprayers. They can be electric or gas powered, with the gas powered systems being the most powerful.
The system is attached to a small hand cart for easy portability. A can of paint is placed in front of the unit, and the intake tube is put into the can of paint. When the unit is turned on, a piston moves up and down, effectively pulling the paint up into the pump. Then the paint under pressure is pushed through the air hose and out of the spray nozzle once the trigger is pressed. There are adjustments on these sprayers in order to regulate the amount of paint that comes out of the nozzle, which helps regulate the speed of painting.
A membrane pump works the same way as the piston pump, but instead uses a strong membrane, a thin pliable-layer of rubber material, in place of a piston. The membrane is vibrated at high rates in an up and down movement doing the job of a piston.
These types of sprayers are the most expensive, but are very durable with better flow adjustments. They also allow a wider range of nozzle sizes which can provide a wider or more narrow spray, along with fine and heavy spraying.