Advantages of Spraying with Electrostatic Guns

Electrostatic applicators offer high transfer efficiency, less VOCs, faster production

Spraying with manual electrostatic applicators has several advantages. Electrostatic guns have very high transfer efficiency which means less money spent on paint, less VOCs (Volatile Organic Compounds), less clean-up and faster production. They also provide excellent finish quality.



Solvent-borne coatings

Solvent-borne coatings, including low, medium and high solids coatings, enamels, lacquers and two-component coatings, can be trusted to provide tough, durable finishes. These coatings are often applied with air spray or air-assisted airless technology.



• Air spray electrostatic spraying uses a low-pressure fluid stream that is mixed with compressed air at the air cap to atomise material in a controlled manner. It is used for the application of low to medium viscosity fluids for products requiring a high quality, Class A or decorative finish.
• Air-assisted airless electrostatic spraying uses a high-pressure fluid supply for atomisation and compressed air at the cap for pattern control. Air-assisted airless electrostatic spraying solves many problems that arise with the use of high-viscosity and high-solids coatings, and other issues associated with heating and using higher fluid pressures to aid in the atomisation of more viscous materials.



The wrap-around effect

Electrostatic applicators charge material particles as they pass or contact an electrode to achieve higher transfer efficiency. They rely upon the attraction of opposite electrical charges.

1. The material is electrostatically charged as it passes through an electrostatic field produced between the electrode on the front of the gun and a grounded object.
2. The charged particles of the material are attracted to the grounded (neutral) object and form an even coating.
3. The charged material then wraps itself around the object, increasing the surface space that is coated.

Because of this wraparound effect, electrostatic applicators are especially suitable for coating tubular products.

Many parameters determine the efficiency with which the material can wrap around the surface. These include:


• Polarity of the coating
• Voltage potential of the spray gun
• Air velocity in the spray booth
• Efficiency of the ground 

Coating resistivity

To determine the correct coating to use in an electrostatic gun, you must consider its resistivity. The materials, solvents and reducers used in the manufacture of the coatings determine the resistivity of the coating.

This can be measured with a paint probe meter that measures megaohms per centimetre of resistance. The best electrostatic results are achieved when the resistivity of the coating is between 25 and 50 megaohms per centimetre.

Getting the paint formulated from the manufacturer for electrostatic use is typically the best solution.



Water-Borne Material

While solvent-borne coating systems still remain the benchmark for overall performance, application and appearance characteristics, water-borne materials are growing in popularity because of more stringent air quality regulations. They contain and emit less organic solvent into the atmosphere while providing certain refinishing benefits and offering lower toxicity.



Water-borne materials have low resistivity, therefore, require different handling when spraying with electrostatic guns. Traditionally, spraying water-borne materials with manual air spray applicators required either conventional air spray guns or for electrostatics, an isolation system. Both methods have their disadvantages.

Conventional air spray guns do not deliver the transfer efficiency or wrap that electrostatic spraying delivers. In addition, if electrostatic automatic applicators are used in the finishing process, colour match can be difficult because of the various material types used in certain applications. While isolation systems address these issues, they are difficult to work with in a high production facility.



One alternative for spraying water-borne materials with electrostatics is an external charging electrostatic applicator. The external charging electrostatic gun can be connected to a circulation system or a pump system. The water-borne material is charged as it is exiting the gun through an electrostatic field. The external charging electrostatic gun eliminates the need for an isolation system. 


In addition, water-borne electrostatic guns have the advantage of delivering higher transfer efficiency and higher productivity then conventional air spray guns. Because of these cost saving benefits, smart consumers are replacing existing conventional air spray guns with water-borne electrostatic spray guns on a circulation system.



Electrostatic vs. conventional paint spray guns

Overall, the difference is clear. Electrostatic spray guns not only provide better finish quality, compared to conventional air spray and HVLP guns, they also reduce VOC emissions and improve production speeds.

Consider the benefits of switching to electrostatic technology before purchasing another gun for yourself or for your business.