Airless spraying is a spraying system that does not use compressed air. Traditional sprayers use compressors to generate air to atomise paint.
Airless systems pump paint through a hose at extremely high pressure (typically 2000 psi) into the spray gun. The paint is then forced through a tiny orifice (17 thousandths of an inch), which breaks the paint stream into a mist.
Airless spraying is extremely fast. Some sprayers can apply 5 litres of paint per minute, equivalent to 60 square metres per minute. In practice, if you are spraying a room, the application rate is approximately 6 square metres per minute. If you want to know how much time you can save using a sprayer, a typical 50-square-metre room can be completed in about 8 minutes.
What does an airless sprayer include?
In addition to understanding how to use the sprayer, you should also be familiar with some of its basic components. These components include:
1. Pump
It has a suction tube that can be inserted into the paint, pumping the paint through a hose to the spray gun. The size of the pump determines the sprayer's operating speed. A small pump may only dispense 1.9 litres per minute, while a larger (and more expensive) pump can dispense 5 to 10 litres per minute.
Most airless sprayers use piston pumps. The size of the piston is one of the factors that determines the sprayer's paint application speed.
2. Hose
The standard airless system hose is 15 metres long. This allows contractors to secure the pump in one location and reach all corners of the house. Hoses are available in various lengths, and shorter hoses are recommended for use in confined spaces.
The hose has been tested at 12,000 psi and is relatively rigid with limited flexibility, especially under pressure. To facilitate spraying, it is recommended to add a whip hose (a short, flexible hose) between the hose and the spray gun.
3. Gun
A spray gun is simply a device that controls the flow of paint through a trigger. The spray gun handle has a filter to ensure no large particles block the nozzle. Once the nozzle is inserted into the spray gun, it converts the paint flow into a spray. The nozzle determines the spray width and paint volume. This makes setting up the spray gun very simple, as the nozzle does all the work; there are no knobs or dials.
Airless Sprayer Equipment Checklist
We have created a simple table containing all the basic airless sprayer equipment you need.
Equipment Purpose
Airless Sprayer Uses a high-pressure pump to spray paint. The paint is sprayed from the nozzle at a pressure between 1000 and 2500 psi, sufficient to atomise it without air.
There are also many high-quality airless sprayers available on the market at various price points.
Clean Valve We call it the Swiss Army knife. It is installed at the end of the extension rod to prevent splashing. There is an additional valve at the end of the rod that cuts off the flow of paint when you release the trigger.
Diaphragm Pump Unlike piston pumps, the pump is designed to use a flexible membrane and pulsating hydraulic oil to generate pressure.
Electronic Pressure Control Regulates pressure electronically rather than mechanically to provide more precise control.
Fine Finish Tip A specially designed nozzle for surface atomisation where a better surface finish is required, such as on doors and skirting boards.
Orifice A small hole (measured in thousandths of an inch) on the tip through which the paint passes. The second part of the number engraved on the tip indicates the size of the spray hole, e.g. 517 indicates
a 17 thousandths of an inch spray hole. The size of the spray hole determines the amount of paint applied to the surface. The larger the spray hole, the greater the paint volume.
Packing Material used to seal the piston and generate pressure. It needs to be replaced every few years.
Extension rod An extension rod attached to the end of the spray gun, which can be tightened to increase the spray gun's working range. Various sizes are available. It can be used for painting ceilings or making wall spraying easier. If needed, tighten the extension rod to increase the operating range.
Roller A roller installed at the end of the extension rod, fed with paint by the airless sprayer. It eliminates the need to repeatedly dip the roller into the paint, theoretically reducing overspray.
Return tube When the pump is in start mode, the smaller tube returns the material to the paint container.
Nozzle Inserted into the nozzle guard, it is the working end of the airless sprayer. It controls the fan width and the amount of paint sprayed onto the surface. These components wear out and need to be replaced after use.
Throat Seal Liquid Also known as ‘TSL.’ A lubricant stored in a small cup at the top of the piston to keep the packing moist and lubricated. It needs to be replenished every four hours during continuous use.
Benefits of airless spraying
Here are the reasons why decorators use airless spraying equipment:
Speed — Using a spray gun is much faster than traditional brush and roller methods, meaning you can complete more work in less time.
Profit — Completing more high-quality work in half the time means earning more money.
Finish — When you know how to use a spray gun correctly, you can achieve stunning results, especially on woodwork and kitchen cabinets.
Ease — Spraying ceilings is much easier than rolling them, and spraying baseboards is much easier than brushing them.
Fun — Spraying is a lot of fun. We’ve seen that once decorators master the use of a spray gun, they can enjoy the process again.
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