Optimizing spraying results with electrostatic paint sprayer guns
To get the full advantages of electrostatic paint sprayer guns, you must understand how they work and which coatings to apply.
Spraying with electrostatic spray guns provides an excellent finish quality. Electrostatic paint guns also deliver a very high transfer efficiency of up to 90%, resulting in cost savings for paint, a reduction of VOC (volatile organic compounds) emissions, less cleanup and faster production.
To take advantage of the benefits of electrostatic paint sprayer guns, you must understand what materials can be sprayed, which coatings to use and how to optimise the transfer efficiency of the manual gun.
ELECTROSTATIC PAINT SPRAYERS FOR LOW TO HIGH VISCOSITY
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 as well as other issues associated with heating and using higher fluid pressures to aid in the atomisation of more viscous materials.
HOW ELECTROSTATIC SPRAYING SYSTEMS WORK
Electrostatic spray guns charge material particles as they pass or contact an electrode to achieve higher transfer efficiency. They rely on the attraction of opposite electrical charges. 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. The charged particles of the material are attracted to the grounded (neutral) object and form an even coating. The charged material will then wrap itself around the object, which will increase the surface space that is coated.
OPTIMISING THE WRAPAROUND EFFECT OF ELECTROSTATIC SPRAY GUNS
Because of this ‘wraparound’ effect, electrostatic spray guns are especially suitable for coating tubular products. Many parameters determine the efficiency with which the material can wrap around the surface.
- Polarity of the coating
- Voltage potential of the spray gun
- Air velocity in the spray booth
- Efficiency of the grounding
DETERMINING THE CORRECT COATING
To determine the correct coating to use in an electrostatic paint 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 megohms per centimetre of resistance. The best electrostatic results are achieved when the resistivity of the coating is between 25 and 50 megohms per centimetre. Getting the paint formulated from the manufacturer for electrostatic use is typically the best solution.
SOLVENT-BORNE VS WATERBORNE COATINGS
While solvent-borne coating systems remain the industry standard, waterborne materials are quickly growing in popularity and taking market share 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.
Waterborne materials have low resistivity and therefore require different handling when spraying with electrostatic guns.
WHY CHOOSE WATERBORNE ELECTROSTATIC SPRAY GUNS?
Electrostatic guns not only provide better finish quality and higher transfer efficiency compared to conventional air spray and HVLP guns, they also reduce VOC emissions and improve production speeds. Smart consumers are replacing existing conventional air spray guns with waterborne electrostatic spray guns on a circulation system.
THE ELECTROSTATIC BENEFITS WITHOUT AN ISOLATION SYSTEM
One of the major advantages of electrostatic spray systems for waterborne materials, such as HydroShieldTM, is that they no longer require a cumbersome mixing room. Combined with the professional Pro XpTM WB electrostatic spray guns, this easy-to-use spraying solution delivers excellent results.
SPRAYING WATERBORNE MATERIALS: A CHALLENGE?
Traditionally, spraying waterborne materials with manual air spray guns required either conventional guns or, for electrostatics, an isolation system. Today, electrostatic systems like HydroShield are sold as complete off-the-shelf solutions, with no need for new mixing rooms or complex system set-ups. The HydroShield system is easy to install, and its parameters can be adjusted in seconds through its operator-friendly control module.
Consider the benefits of switching to electrostatic technology before purchasing another gun for yourself or your business. Be sure to check out the HydroShield system, one of the safest and most operator-friendly electrostatic spraying solutions on the market.
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