I am the production supervisor for a company that makes steel office furniture. We are proud of our paint job and the appearance of our painted products. We recently sold some furniture to a jobber in the southwest, where the humidity is high and have gotten complaints about rusting of the inside surfaces of drawers and cabinets. Naturally, we had a staff meeting to discuss the problem. After some investigation of this problem, we noticed that we often do not get paint on all the internal surfaces of cabinets and drawers and we get overspray on the inside compartments of steel drawers where we don’t want it. How can we eliminate overspray on the interior compartments of drawers? Furthermore, how can we get paint onto the difficult and inaccessible areas of cabinets? Our problem is mostly on internal structures and behind internal supports. S.L.
It is often possible to eliminate overspray onto inside surfaces and other areas by masking before spray painting. Paint can be applied on otherwise inaccessible areas by using the electrostatic spray application method. This method will generally cause paint to be deposited behind internal supports. The exception to this rule is the inability to paint inside corners because of the well known “Faraday Cage” effect.
The most efficient way to paint internal and external surfaces of complex shaped objects is the electrophoretic paint deposition method commonly called electrocoating. In this process, the product is immersed in an aqueous bath of paint, which is the electrolyte, the product is the anode or cathode and the tank wall or some auxiliary part is the other electrode in a DC circuit. With the application of voltage during the electrocoating process, the paint is coated onto the surface of the metal evenly and completely, inside and outside.