There are many key factors that must come together to be able to use electrostatic guns effectively. First you need to select the right atomization technology for the coating application needs. There are many electrostatic atomization technologies to select from. The oldest and probably most typical are the air spray electrostatic guns. These guns use compressed air as their primary and sole method of atomizing the coating. These guns are most commonly used in applications that want a “Class A” automotive finish. The guns offer lots of control at the gun such as for instance fluid flow by the usage of the fluid needle adjustment knob and fan control through the utilization of the fan adjustment knob. Additionally, the total amount of fluid may be controlled by how far back the operator pulls the trigger. That is known as “feathering” the gun.
The main source of fluid control is determined by the fluid pressure from the low-pressure pump, the air going into a force pot or with a fluid regulator mounted near, or in the spray booth. The viscosity of the coating and how big the fluid nozzle also affect the fluid flow. polyurea though air spray electrostatic guns have great atomization, they are also the smallest amount of efficiency of the electrostatic guns. That is due to the potential usage of high air pressure to atomize the coating. The utilization of high air pressure can defeat the electrostatic attraction by forcing the charged particles of paint after dark part or by creating excessive bounce back or overspray.
An alternative of the air spray electrostatic gun may be the HVLP electrostatic gun. The gun operates almost identically to the air spray gun except that it uses less atomizing air pressure. Instead, the gun uses more cubic feet of compressed air or CFM. The effect is a softer spray pattern that lowers the velocity at that the paint particles travel. This enables for more of the charged particles to keep in the electrostatic field which supports to improve transfer efficiency. Like any HVLP gun, some coatings might be too viscous or the applying rate might be excessive, which may allow it to be burdensome for the HVLP electrostatic gun to provide high productivity and acceptable finish quality for many applications. Additionally, HVLP guns usually require more CFM which could result in increased electrical costs for compressed air.
For the applying of very viscous materials and for very good application rates, some manufacturers use airless electrostatic guns. These guns use pumps to generate very good fluid pressure which is the primary method of atomizing the coatings. When the gun is triggered, the high fluid pressure is allowed to escape to the atmosphere via a tungsten carbide tip that’s cut to make an elliptical spray pattern. How big is the pattern and the total amount of fluid leaving the gun are controlled by the tip. The viscosity of the coating and the fluid pressure used also affects the applying rate.
Generally, airless technology doesn’t provide the same amount of atomization as air spray or HVLP electrostatic guns however they work nicely for many coatings, specially when spraying large products at high rates of speed. Tip plugging is definitely an issue when spraying materials that contain an aggregate such as for instance silica or zinc. Air-assisted airless electrostatic is really a hybrid version of the airless electrostatic and the air spray electrostatic. These guns use both fluid pressure and air pressure to atomize the coating. Pumps are required to generate the fluid pressure. Since these kinds of guns use lower fluid pressure than airless and less air pressure than air spray, they could offer companies a great compromise between the speed of an airless and a finish quality closer to the air spray electrostatic. The most effective part is this technology is generally better than either the air spray or the airless electrostatic guns. In some instances, they are even better compared to HVLP electrostatic guns.
However, air-assisted airless electrostatic guns do not offer the same amount of control at the gun while the air spray or HVLP electrostatic guns. This is because the fluid pattern can’t be fully adjusted from very narrow to very wide without changing the tip. Also, like the airless electrostatic gun, the operator cannot feather the gun. This may be problematic when spraying very complex substrates where the operator needs that kind of control at the gun. Tip plugging may also be a concern with some aggregate filled materials.
The absolute most efficient manual electrostatic spray gun is really a handheld rotary atomizer. These guns use centrifugal forces and a very good voltage electrostatic field to atomize the material. While there is no atomizing air the paint particles travel very slowly through the electrostatic field. The effect is very good transfer efficiency. However, the gun creates a doughnut-shaped spray pattern that doesn’t work nicely for many production finishing applications and can be used mostly for the on-site refinishing industry.