Techniques of Paint Application

The most common methods of paint applications are brush and roller, air or airless spray, roll coating, electrostatic spraying, electro deposition, and dip coating. Many factors affect the choice of method to be used for a particular application. These include film thickness, appearance requirements, and operating cost. 

Pad applications are also used. The most common type of pad consists of a sheet of nylon pile fabric attached to a foam pad that is attached to a flat plastic plate with a handle. Pads hold more paint than a similar width brush and can apply paint up to twice as fast as a brush. 

Spray painting is a widely used application technique for most industrial maintenance and commercial architectural jobs. Spray painting is much faster than using brushes, pads, or rollers. A large variety of spray equipment is available, including air, airless, plural spray, and electrostatic. 

In conventional air spraying, compressed air and paint are supplied to the spray gun, which atomize and transport the paint to the article being coated where they are deposited forming a uniform film. The air pressure used in this operation is critical and it should be kept at the minimum required amount, to atomize and deposit the paint onto the substrate. 

Direct roll coating method is used for coating thin-gauge sheets or coil stock. The sheet stock is fed between applicator rollers rotating in the same direction as the moving sheet. The apphcator rollers are fed by smaller pick-up rollers that are partially immersed in trays containing the paint. The coat sheet is subsequently fed into an oven for baking. 

---