Airless paint sprayers force the paint through a paint spray gun, thus atomizing the paint, which then comes out through a small aperture at a high pressure, similar to a garden hose attached with a spray gun. Instead of a compressor, the pressure applied on the liquid comes from a piston pump unit or a motor driven diaphragm. They are called airless paint sprayers, because compressed air is not used in order to provide the pressure required.
The size of valve's opening and the horsepower are the two numbers you need to check, when you want to determine the capabilities of a unit. Bigger sized pumps with larger valves are able to handle heavier paint coatings.
A wide range of finishes and coatings can be applied by them in less time compared to other methods. Plus, they can be used to apply the coating of whatever thickness you want.
They are usually not used for spray painting jobs that require detailed work, such as cars or cabinets. They cannot be used for such applications, because they apply too much paint too fast. They are ideal for exterior and interior surfaces such as buildings or fences. They are available in various designs and configurations, however, all of them generally have the same controls and features. It requires a lot of pressure to force a heavy fluid like paint through the small hole at the tip. Plus, there has to be an adequate pressure in order to maintain a proper pattern of spraying that comes out of the tip.
Types of Airless Paint Sprayer Pumps
The airless paint sprayer's basic components are: a pump, hose, gun, and the tip. There are two types of pumps ― the piston and the diaphragm ― and both of them work very well. Although the diaphragm type cannot pump very thick paint, which the piston type can handle very well. Hence, the piston pump types are more versatile.
The Piston Pump: It comprises several components which include a piston, check valves, and packing. When the piston moves up, it creates a vacuum so that the paint is sucked up inside a chamber, known as the fluid section; and when the piston comes down, it pushes the paint into a high pressure hose.
A seal is created by the packing, so that there is no loss of pressure during the work. The airless paint sprayers used by professionals are equipped with packing that is self adjusting, which prevents premature wearing and the requirement for repairs.
The flow of the paint from the pump's fluid section to the hose is directed by the check valves, or the ball and seat valves. This helps in preventing the paint being pumped backward through the pick-up tube.
The Diaphragm Pump: A piston is also used in the diaphragm type, although in a different manner. Hydraulic fluid is moved by the piston in order to move the diaphragm, which results in paint being sucked up and being pushed through the hose and the gun.
The diaphragm is not touched by any moving parts. The piston's and the hydraulic fluid's movement result in the diaphragm moving up and down in a very rapid manner. Although no packing is used in this design, check valves have to be used.
This method of application requires a high-pressure hose, which is rated according to the pump's maximum output of pressure. Typically, the operating pressure is 3000 psi. This hose is very tough, which has the ability to withstand considerably high amounts of pressure and is kink resistant. It is advisable to never try to repair this hose as it can result in an injury. Instead of repairing, it is better to replace it.
The Airless Paint Spray Gun
The airless paint sprayer is controlled and its tip is held with the help of a spray gun. It looks like a handgun due to a trigger and a handle. As soon as the trigger is pulled, the valve opens, which allows the paint to flow through the tip on to the surface that is being painted.
When choosing a spray gun, it is important to look for the comfort factor. They are either 2 or 4 finger guns. These numbers indicate the number of fingers required to pull the trigger.
The choice of the spray tip is dependent on the pump's capabilities as well as the type of paint being sprayed. Its choice will have an effect on the effectiveness and performance of the sprayer.
These are the main components of all airless paint sprayers. Your requirements and expectations will determine the type you choose to buy. Keep in mind that thicker the paint, the more power you will require.