China Powder Coatings

  The powder coating process requires some specialized equipment. The powder used can be one of two types: thermoplastic or thermoset. Thermoplastic powder becomes softer and more liquid when heated. In this case, there is no chemical bonding, which makes this form of powder coating reversible and reusable. Thermoplastic coatings are thicker and more durable than thermoset coatings, and for this reason, they are used on everything from refrigerators to auto parts to metal fencing.   Thermoset powder coatings work a little differently. They form chemical bonds when cured, which means they cannot be recycled in the same way thermoplastics can. They are ideal for high heat areas, as these bonds make them unlikely to melt away as thermoplastics would in the same situations. Thermoset coatings are often the cheaper of the two.   Once the type of coating is decided, the first step in the powder coating process is preparation. This is perhaps the most important part of any project, as it will determine how well the powder coating adheres to the surface it is intended to protect. Preparation can involve sandblasting as well as using a primer before applying the powder coating.   Powder coatings are usually applied using an electrostatic gun, which charges the powder before it is sprayed onto a surface. Then, the powder is sprayed onto the desired surface using compressed air. After the powder has coated the object’s surface, curing can begin, during which time the surface is heated to allow the powder to melt and form a film. Once it cools, the coating hardens, and the process is complete.   There are other methods of applying powder coatings, though they can be problematic or are only suitable for certain types of projects. For example, a metal surface may be heated prior to applying the coating, which allows the powder to melt on contact. The problem here is that it may cause excess powder to run, which creates more work and may require the process to be redone. Electrostatic fluidized bed coating is another method of powder coating and is a dipping process that cannot be used on larger pieces.