What is Powder Coating
Powder coating is a popular industrial coating method used on metals, plastics, and some specialty wood products. The ability to create a decorative and durable finish in a range of colors and textures makes powder coating very popular for industrial top coatings.
Main Benefits of Powder Coating Metal:
- Friendly for the Environment: Strict compliance regulations met with little to no waste of raw materials. Zero VOCs (Volatile Organic Compounds) emitted.
- Custom Color Options: Choose unlimited colors.
- High-level of Protection: Strong and durable finish that provides protection against chipping and scratching.
- Longevity: The coating can last decades, even in harsh environments
A powder coating polymer system is made by mixing curatives, leveling agents, flow modifiers, pigments, and a few other items. Additives are mixed and melted, cooled, and then made into a powder that has a similar look and feel to powdered sugar. A spray gun is then used to create an electrostatic charge, which allows the powder to attract to the prepped base material.
Following the spraying process, the powder coated component is then placed into a curing oven where the coating is allowed to chemically adhere. The oven’s heat helps the sprayed coating create molecular changes, providing a shell that’s long-lasting. The finish can be done as satin, matte, or gloss.
While often overlooked, the overspray reuse is another benefit of the powder coating method. The application method allows for overspray to be collected when it does not adhere to the components. This eliminates a significant amount of waste compared to liquid coating systems like painting or staining.
After the powder coating is applied, there’s regular maintenance that must be performed to keep it clean and make it less susceptible to penetration. Once penetrated, the corrosion resistance will be compromised as humidity and moisture will be able to reach the underlying layer of material. Powder coating is porous and can be damaged under extreme force. If regular maintenance is not performed, the coating can fail in a relatively short period of time. Extra care should be taken when installing powder coated components. Any damage should be addressed right away.
How to Maintain Powder Coated Surfaces:
- Avoid Harsh Solvents and Cleaners: Certain chemicals in commercial cleaning products can damage the coating. Think of it like the paint on your car, you wouldn’t want to use cleaners with abrasive or harsh chemicals on its finish.
- Clean with Mild Soap and Distilled or Filtered Water: If the water has high amounts of chlorine, iron, sulfur, or fluoride, it could cause staining and weaken the coating.
- Use a Top Layer of Wax or Ceramic: When finishing your coating, use a wax or ceramic layer to add further protection against harsh elements and temperatures.
- Use Your Eyes and Inspect Often: The best way to maintain is to stay ahead of potentially larger issues. If you see a scratch, chip, or start of rust, look to repair it before it gets worse.
What is Galvanizing?
Like powder coating, galvanizing is the process of applying another layer of protection. However, galvanizing is the process of adding a layer of zinc for this protective coating. The zinc coating will give metal objects tough protection against corrosion and rust.
The most common way to galvanize is with hot-dip galvanizing, in which parts are submerged into a bath of molten zinc. The base metal is first thoroughly cleaned (mechanically or chemically) to insure that the zinc will bond for a long time. After cleaning, the base metal will be fluxed to remove remaining oxides. It will then be dipped into the zinc.
Top Benefits of Galvanizing Metal:
- Less Maintenance: They are self-maintaining and thicker. The maintenance costs of these steel items are inevitably lower.
- Long Life: Steel items can last more than 50 years.
- Lower Costs: Lower initial costs compared to other commonly specified corrosion protection coatings for steel.
- Quick Application: It only takes a few minutes to apply a full protective coating.
Find out more about galvanization here: https://www.erectastep.com/what-is-galvanizing/
Which is Better?
Powder coating is typically viewed as the favorite for most common industrial applications. When it comes to rough environments, however, like lumber yards, foundries, shipping docks, or high/low temperature atmospheres, galvanizing is the favored process. Powder coating takes longer to apply but has more flexibility with finish and color. Both methods provide a protective finish to metal components, with powder coating being easier to damage under forceful impact.
Powder Coating vs Galvanizing Comparison
|Requires Thorough Cleaning Prior to Coating||✅||✅|
|Reusable Raw Material||✅||✅|
|Very High and Very Low-Temperature Resistant||✅|
|Endless Color Options||✅|
|Low Maintenance Once Applied||✅|
Look to use both methods for the best protection possible. You can powder coat a galvanized surface, so if you are after the highest durability and a nice appearance, this is a great way forward. The specification ASTM D7803 contains details on how to prepare the hot-dip galvanized surface for powder coating.