The airless painting
22.02.2017
Airless application technology involves passing a fluid with high-pressure through a small nozzle (spray tip). The fluid exits the tip at full speed as a solid stream (sheet), hits the air and becomes disrupted. This disruption brakes fluid into fragments initially and ultimately in very small droplets that form the spray pattern.
In airless application, paint is pumped at high pressure and then by releasing it through the airless gun tip it is atomized and projected on the base support. By changing the diameter of the nozzle and spray angle, or by changing the fluid pressure, atomization can be achieved for a wide range of viscosities.
Why choosing airless painting?
This spray type enables an uniformly thick layer of paint by just one pass, which reduces the number of passes needed to achieve the desired end result.
The paint penetrates better in holes, cracks, and corners providing better protection in time.
Most paints can be sprayed without added thinner, which leads to reduced drying time and release into the environment of solvent.
When is airless painting truly useful?
Airless method is used for applications where efficiency in applying comes first instead of finish quality, especially in heavy industries, metal, petrochemical, and marine industry. Depending on the viscosity, the pressure required for atomization, the total flowrate and energy source, one can choose from a wide range of pneumatic or electric pump motors.
A variant derived from an airless paint spraying is the air assisted airless, material being delivered to the gun at a lower pressure than in case of traditional airless version, allowing the final atomization to take place by adding an airflow. This method offers much more control in the spraying process, a higher quality of the finish and a better transfer rate.
A solution for highly viscous materials, with up to 100% solid content, is the warming of paint in order to reduce its viscosity, instead of diluting it, thus yielding higher layer thicknesses. This is a method that is common when applying materials without solvent (solvent free), which are usually two-component ones (“mix-at-the-gun”) ones and is used mainly in the petrochemical industry.
