Glossary

Electrostatic coating

(ESTA)

here, an electric field is created between the coating device and the item being worked on that charges the lacquer being sprayed (by means of a spray column, rotational bell painting, spray disk or gun) (40-90 kV voltage and 0.2 mA current). The droplets of lacquer attach themselves to the item being worked on according to the direction of the electrical field lines, and in doing so the rear is partially covered as well. The prerequisite for this procedure is to have a certain amount of electrical conductivity, something that metals always have, with wood requiring a minimum moisture content of 8-10% and the spray booth requiring air humidity of 60-70%. The advantage of this procedure lies in application being mostly waste-free, as practically all of the material sprayed hits the item being worked on. This is particularly significant when coating table and chair structures, frames, etc. A hand-held electrostatic spray gun is used for applying the lacquer. In the same way, this procedure is suitable for powder coatings. Specialist guns with external charging or another specialist system are required for water-dilutable coating systems. This waste-free coating procedure requires a flashpoint of over 21°C

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