More than 40 years ago, powder coatings were introduced into the United States and Canada. It had first appeared in Australia in 1967. As such, it was the youngest form of finishing – particularly when compared to plating. Powder coating remains popular, holding approximately a 15% share of the entire industrial finishing market.
Basic Types of Powder Coatings
A finisher who utilizes powder coatings as a method of producing the right qualities and finish can choose between two major types of powder, which are:
* Thermoplastic Powders: This type will melt again if heated.
* Thermosetting powders: This type of powder coatings won’t melt again if reheated.
Either may be used in one of the techniques used to apply the powder coatings to the component.
Two Techniques for Powder Coatings
At its basics, powder coatings is a method that is simple in intent. The operator applies dry paint to a component or other object. The powder coatings may be applied in several ways, but two techniques are most common in the industry. They are:
* Dropping the item to be coated into a fluidized powder bed. The choice is between electrostatically charging it or not
* Spraying an electrostatically charged powder coating onto the component
Following either process, the newly powdered component is placed in an oven. This causes the powder particles to melt. They then merge creating a continuous protective film.
Tools of Application
Some methods employ electrostatic tunnels. More frequently, however, powder coatings are applied with a “gun.” At least three types of guns are used in the trade by surface finishers. These are:
* “Bell” Charging Guns: The powder used in the coating is charged when it “flung” from the perimeter of what is termed the “Bell”
* Corona Charging Guns: These guns are internally or externally charged to load the powder
* Tribo Charging Guns: The friction that exists between the gun barrel and the powder is responsible for creating the necessary charge
The method chosen will be influenced by the product being treated, the surfacer, the client and the finishing company.
Why Use Powder Coatings?
Powder coatings are applied to a broad range of products. Industrial manufacturers request this type of treatment for many reasons. Some have to do with the quality the powdering affords; others are the result of the aesthetic look that the process produces. The primary reasons companies want powder coatings include:
* Appearance: High-quality finish
* Durability
* Improved efficiencies
* Environmentally friendly: Powder coatings meet the increasingly strict restrictions
* Diversity: Colors, shades and hues are almost limitless
* Abrasion resistant
Powder coatings are found on outdoor and indoor machinery. They are applied to indoor appliances and other household items. Indeed, everywhere you go you pass by items that have been coated in this manner. If nothing else, powder coatings can be said to impart three enduring and endearing qualities: tough, durable and attractive
