Powder coating is a finishing method for metal that is an alternative to paint, and it is often preferred because the result is more durable, the spray generates less waste, and the whole process is less expensive than painting. Powder coats come in a variety of colors and tones that can achieve almost any desired look. The process of applying a powder coat involves the following three steps.
Before applying a powder coat, the technician will first prepare the metal so that the coat will adhere well. The treatment is designed to remove any scale, dirt, or grease from the metal and in some cases, apply a mineral coating. The type of pre-treatment used depends on the type of metal to be coated and its condition. For example, steel is typically pretreated with zinc phosphate while aluminum is treated with a chrome/phosphate immersion. Most pre-treatment processes involve multiple stages of cleaning, immersion, rinsing, and sealing.
The powder coat may be applied through an automated or manual process. An electrostatic gun gives the powder a positive charge as it is sprayed onto the substrate (metal), which has a negative charge. Thus, the powder particles adhere magnetically to the metal. This significantly reduces the overspray that commonly occurs with spray paint. The magnetic attraction also ensures an even distribution of the powder over the item. Once the metal item is completely coated with powder, it is placed in an oven and heated until the particles fuse and harden into a smooth coat. Once the coat has hardened, a second finishing coat may be applied.
The final phase in the powder-coating process is to heat the item until it is fully cured. There are several common methods of curing. Applying gas-powered radiant heat is a method that quickly heats the outside of the item without penetrating the inside. A convection oven is another curing method that circulates heated air and is ideal for curing multiple items at once or for curing large items. A box oven is another method used for especially large or delicate items.
Once the powder-coated item comes out of the oven, it is ready to be used within 20 minutes. To learn more about the powder-coating process, visit http://www.custom-powder.co.uk/.