Surface finishing is essential for the practical use of industrial metal products. Metals such as ductile iron and stainless steel can be protected as well as given a glossy feel. The colorful exterior of your end products is not only decorative but also acts as a potent barrier to corrosion and abrasion.
The metal coating industry has grown in leaps and bounds. Individually, the global powder coating market currently stands at $12.48 billion. Technological advancement has enhanced protective coat applications leading to the production of more durable products. However, there is still a debate among experts on whether powder coating is superior to wet painting and which of these methods is better. Read on as we dig deeper to find out the basic principles of both and why powder coating is becoming more popular.
Professional powder coating is a finishing process where a dry powder is applied electrostatically to a metal surface and placed in a curing oven to complete the coat. The powder contains resins made from either polyester, polyurethane, polyester-epoxy, or acrylic.
The metal is initially prepared for coating through sandblasting that removes any rust, oil, or debris. The dry powder is sprayed electrostatically where the powder is negatively charged and binds tightly to the metal surface. You then place the metal sheets in a curing oven for the powder to melt and coat evenly on the metal surface.
There are two main categories in the dry powder application process:
- Thermosetting: Involves the addition of chemicals and other resins that are blended with the powder. The powder is electrostatically applied and then heated to form chemical bonds between the molecules, which form a tough coat over the metal surface.
- Thermoplastic: There is no addition of other chemicals, and the powder melts and flows, fusing with the metal.
Wet Paint Coating
Wet painting is the more traditional process that involves applying liquid paint onto a metal product for a colorful finish. A spray pump or a pressurized vessel is used to spread the wet paint evenly on the metal surface. The liquid paint may contain added resins and chemicals that help form a tighter, firmer coat.
The preparation for coating is similar to that of powder coating. It involves wet blasting the liquid paint evenly over the metal surface for a gloss finish. For liquid coatings, a curing oven may not be necessary, though it is often used.
Which Method Is Better?
The answer may not be straightforward as both processes have their pros and cons. However, professional powder coating is slowly gaining popularity over wet paint. First, powder coating offers more durable finishes than conventional painting. The thick, dense coat offers better protection and is long-lasting.
Secondly, the powders do not release volatile organic compounds and are, therefore, friendlier to the environment. Powders allow you to be compliant with Environmental Protection Agency regulations. Additionally, a professional powder coating allows you to implement multiple custom finishes.
Metal surface finishing is vital for enhancing durability and colorful exterior designs. Selecting between professional powder coatings and wet paints depends on what you want the final product to look like. However, powder coating has an edge over traditional painting in terms of durability and environmental friendliness.