Views: 6 Author: Site Editor Publish Time: 2023-11-14 Origin: Site
Powder coating is a popular alternative to liquid paint, offering superior durability and corrosion protection. The process involves spraying the item to be coated with a special gun called a Corona gun, which gives it an electrostatic charge.
Unlike wet paint, it doesn’t release volatile organic compounds into the air. This helps reduce the cost of pollution control equipment and minimizes short- and long-term health risks for workers.
Clean the Surface
Powder paint is much more resistant to things like rust and corrosion than standard wet paints. However, this does not mean that powder coated items don’t need regular cleaning and maintenance. For example, powder coated metal surfaces should be wiped down regularly to remove any dust or debris. It’s also a good idea to use a mild soap in water to clean powder-coated items. Harsh cleaners or solvents can actually damage the finish and leave it more vulnerable to deterioration in the future.
The frequency of cleaning and maintenance will depend on the type of environment that a piece of metal is in, and how critical it is. For example, a surface exposed to saltwater might need more frequent washing than a surface inside of a factory. Powder-coated metal should be cleaned with filtered water whenever possible to avoid the potential for harmful chemicals in detergents and other liquids. Then, it should be rinsed and dried completely to avoid stains.
Pre-Treat the Substrate
Whether the powder you use is bonded or unbonded, it will require some sort of pretreatment to work properly. There are many different ways to do this, but the main goal is to prep the substrate so that it will accept a coating and stay in top nick for as long as possible.
Chemical pre-treatment processes usually consist of degreasing, etching, desmutting, various rinses and phosphating or chromating of the metal surface. Newer nanotechnology chemical bonding processes are also available that eliminate the need for chromates, which are toxic to the environment.
These pretreatment stages can be a huge undertaking that requires an automatic line and a lot of space, water treatment and maintenance costs. However, it is a vital step in getting the best results from your paint powder job. Even if your powder is of the highest quality, if the substrate is not well grounded, it will not be able to adhere. A poorly grounded piece will be prone to flash corrosion and other issues that can significantly reduce its life span.
Apply the Powder
Once the surface of your product has been properly cleaned and pretreated, it's time to apply the powder. This process uses an electrostatic spray to adhere pigmented powder granules to the metal. The metallic powder can be applied from one to six millimeters thick in a single pass.
The powder coating process is safer than liquid paints because it does not use solvents that produce hazardous chemicals or volatile organic compounds (VOCs) as they dry. However, it's important to wear proper protective equipment when using a powder coating gun to avoid skin and respiratory irritation.
When applying the powder, make sure that you coat all areas of your product, including those hard to reach places like grooves and decorative slots. Also, try to get the most even thickness possible because thin powder coats may not adhere well or result in a bumpy texture akin to the skin of an orange. You can usually adjust the settings on your powder coating equipment to help you achieve a consistent finish.
Cure the Powder
Powder coating comes in a wide range of colors, finishes and textures. You can get it in smooth, glossy, matte, hammertone and wrinkle metallic finishes. The finish you choose depends on the type of application. For example, objects used in harsh environments will require additional rust and corrosion resistance, while indoor surfaces will need a durable clear coat to prevent fading from UV rays.
Unlike liquid paint, powder coating needs to be cured in order to set. It is best cured in a curing oven, but an everyday kitchen oven will work just fine. The temperature of the oven must be steady and consistent during the curing process. Otherwise, the heat could cause the powder to overheat, which will result in chemically damaging the coating. A curing oven will also produce toxic fumes that need to be vented outside. An ordinary toaster-type oven is not suitable for this purpose because it can’t handle the temperature fluctuations that are required to cure a powder coat.