The Fascinating Process Of Powder Coating Explained

Powder coating is a dry finishing process in which a substrate’s surface is coated with dry coating powder. The powder is then melted and cured into a protective or decorative coating. There are three main stages of the process: pretreatment, spraying, and curing. Learn more about each stage here!

What Is Powder Coating?

Powder coating is a dry finishing process that uses finely ground particles of pigment and resin to provide surface gloss levels, a consistent finish, and a more durable surface than traditional paint. It is available in a wide variety of colors and finishes, and is commonly used for both protective and decorative applications. It can be applied using either electrostatic spray deposition (ESD) or fluidized bed application methods. ESD is the most common method, and typically involves a powder spray booth, powder feeder, electrostatic spray gun and a power unit. When the powder coating is sprayed onto a metal component, it adheres to the surface through electrostatic attraction. The part is then cured by heating the coating to fuse the powder’s atoms with the metal.

Pretreatment

Whether you’re coating steel, aluminum or another metal surface, the final result of your powder coat application depends on a robust pretreatment process. The process is a combination of mechanical and chemical surface preparation that must be completed before the coating is applied. Metal pre-treatment helps your powder coating bond more effectively to the metal, preventing rust and helping it withstand weathering. It also prevents flash rust and improves powder adhesion. There are several methods of pretreatment that can be used, depending on the type of metal and the end use. One method involves etching the metal with an acid-based product that promotes powder adhesion to slick or difficult-to-adhere-to metals. A second method of pretreatment involves phosphating the metal with a solution that converts the surface into a protective layer. Phosphating increases the longevity of treated parts and reduces their susceptibility to corrosion.

Spraying

Once the pretreatment has been completed, the next step in the process is to apply the powder coating. The part is sprayed with an electrostatic gun that imparts an electrical charge onto the powder, which is then attracted to the grounded part. The powder spraying process is different than other coating processes because it uses electromagnetic properties. This requires specialized equipment and the ability to work with various powders, which are made of different materials. This technique can be used on a variety of surfaces, including metals, glass, plastics and ceramics. It is more expensive than liquid paint, but can create a thicker, tougher coating than liquid.

Curing

Curing is the final stage in the powder coating process, which occurs in a curing oven at a defined temperature for a specified amount of time. This allows the powder to fully set and create a protective skin around the object. It also gives the coating a final finish. Once the powder is cured, it will be able to withstand a variety of conditions and resist wear and tear. The process of curing is incredibly important and can have a dramatic impact on the outcome of your finished product. It is essential that you check the technical data sheet for your powder and follow the instructions closely.