An airless paint spraying system gives a glass smooth layer of coating over surfaces that is practically impossible to achieve using a brush or roller.
An Introduction to Airless Spraying
In 1892, Francis Davis Millet is thought to have been the first person to invent a basic spray painting device with Edward Seymour advancing this technique into an aerosol form. Nowadays there are a number of different systems for spray applying paint, but they can be divided into two types, air sprayers and airless sprayers.
Air sprayers push compressed air into the liquid paint in order to break it up into tiny droplets. This is known as atomisation which can also be achieved by pumping high pressure into the fluid through a small nozzle and it is this method that is utilised in airless paint spraying.
There are a wide variety of airless paint spraying machines on the market, but they all have features in common. Basically, an airless sprayer has a pump that forces paint up a hose and out of a spray gun through a very small tip. The nozzle on the end of the spray gun creates a fan pattern of paint onto a surface and the tip size, as well as the pressure level, dictates the rate of paint flow.
How does an Airless Spray Painting System Work?
It is viscosity and surface tension that hold liquids together and atomisation dissipates these to produce a mist of droplets instead of a continuous mass of fluid. In airless spray painting systems the energy produced by the high pressure that is injected into the paint is strong enough to achieve atomisation.
The paint is pushed through a hose then out of a minute hold in the top of a spray gun where it exits in a continuous stream under extremely high pressure. However, when it comes into contact with the air it breaks up into a spray of extremely small droplets.
It is the size of the orficice in the spray nozzle that determines the amount of liquid that exits the gun as well as the fan shaped spray pattern. There are a range of tips to control the atomisation resulting in different spray patterns and sizes.
Why Is It Best To Use Airless Spraying?
- Airless s[ray units are ideal for onsite painting because they can be transported easily. The motors are not too heavy as they are usually less than 1 hp.
- This technique is very versatile in that it can be used in interiors and exteriors on a variety of different types of projects ranging from roller shutter doors to huge expanses of metal cladded roofs.
- If you want to complete a recoating project quickly, then airless spraying in the method to choose. Paint can be applied up to four times as quickly as with a brush and twice as fast a roller. This can save up to 75% of labour time.
- As the airless technique covers large surface areas so quickly, project managers do not have to wait for long stretches of good weather to schedule in exterior projects such as painting roofs.
- Not only does the liquid flow out from the gun quickly and easily, it lays paint on a surface evenly unlike brushes or rollers which leave ridges in the coating.
- The uniform layer of paint produced by an airless paint sprayer is perfect for rough, damaged and textured surfaces such as peeling paint on cladding.
- The coating is thick, so not as many coats are needed as in other methods.
- It gives a flawless finish.
- Unlike the electrostatic method which does not suit water based paints or paints containing metallic particles any type of liquid can be applied using an airless gun.
- Because an airless sprayer applies a very wet coating, this results in good adhesion and the coating is less likely to fail and more likely to last for a long time.