Ever rub a balloon against yourself and make it stick to a wall or other object? That is the basic idea of how an electrostatic paint sprayer works. The rubbing of the balloon causes it to obtain more free electrons, which makes a negative charge. The negatively charged balloon now will stick to neutral or positive objects. Ken Eyestone is our training manager at Exel North America, Inc. And according to him, electrostatic paint sprayers are the way to go to save paint, money and the environment.
- At the tip of the paint sprayer is a small electrode, which creates high voltage electricity. As the paint particles travel at a slow speed through this corona of electricity, they become negatively charged.
- The paint surface is the grounded, positively charged surface, which has a magnetic attraction to the negatively charged paint. As you spray the paint, the paint overspray may initially travel off in a different direction, but will turn back to the positively charged object and stick to it. The paint will stick to any surface that is conductive. Metal definitely. Wood has water in it, and the wetter the wood, the greater the positive charge. Surfaces that include plastic, stucco and wood that are old and very dry will need a thin coat of conductive adhesive promoter applied before painting.
- Electrostatic paint sprayers work well with an oil- or water-based paint. However, water has a stronger positive charge than oil. The paint needs to be able to hold a charge, but not be too conductive. Solvents can be added to paints to make them perfectly charged. Contact the manufacturer of the paint to see what, if anything needs to be added to the paint. The size and velocity of the paint particles is also important. The smaller the particle mass, the greater the attraction. The slower the particle, the greater the effect of the paint charge.
- The benefit of using an electrostatic paint sprayer is in the saving of paint. Expect to use 25 percent to 50 percent less paint. In a big job, that is a lot of paint and money saved. There is less waste which is good for the environment. There is very little overspray to clean, and the paint coverage also has a very nice, smooth look.
- If you have sharp edges, the paint will go on much thinker. The particles of paint are very attracted to corners and sharp edges. Where you have an inside corner, the paint goes on much thinner, if at all. This is called the Faraday Cage Effect. The solution to this problem is when spraying into a corner, the painter paints with electrostatics that are turned off for that part.
- If the surface to be painted is not grounded, the charged paint particles will search for the nearest ground. This will in all likelihood be the painter!
See a Bell Atomizer in Action from our lab demonstrations @