WHAT IS ANODIZING?
Anodizing is a simple electrochemical process developed more than 50 years ago that forms a protective coating of aluminum oxide on the surface of the aluminum. The lifetime of the finish is proportional to the thickness of the anodic coating applied. Aluminum oxide is a hard, durable, weather resistant substance that protects the base metal. The coating may be colored by dyeing or
may exhibit bronze tones through diffraction phenomena produced by the coating. The coating grows from the base aluminum metal by this electrochemical process. The coating is integral to the metal and cannot peel or flake. The structure of the coating is many small hexagonal pores, which are filled with a “seal” that hydrolyzes these pores to fill them with inert aluminum oxide.
ADVANTAGES OF ANODIZING
- Anodizing is harder than powder coated surfaces. Anodizing is better for aluminum in high traffic areas where the coating is subject to physical abuse & abrasive cleaners.
- Anodizing cannot peel off. The coating is actually part of the metal.
- Anodizing gives aluminum a deeper, richer metallic appearance than is possible with powder coatings. This is because an anodized coating is translucent, and one can see the base metal underneath the coating. This translucence may contribute to color variation problems.
- Anodizing is unaffected by sunlight.
DRAWBACKS OF ANODIZING
- Anodizing which is less resistant to chemicals.
- Anodizing is more expensive than powder coating.
- Fewer color choices.
- Weld joints are more noticeable. Grinding, polishing, & cleaning is not covered by material.
WHAT IS POWDER COATING?
The powder coating process is very similar to a painting process except that the “paint” is a dry powder rather than a liquid. The powder sticks to the parts due to electrostatic charging of the powder
and grounding of the parts. Any substrate can be used that can tolerate the heat of curing the powder and that can be electrically grounded to enhance charged particle attachment. The powder flows
and cures during the application of heat.
ADVANTAGES OF POWDER COATING
- Numerous color choices.
- Very durable & UV resistant when proper material preparation, application technique & controls are utilized. 5-10 year life in high exposure to elements.
- Powder is recoverable for reuse.
- No VOC generation therefore no VOC destruction required.
- Less expensive than anodizing.
- Weld joints, grinding, & polishing marks are covered making them less noticeable.
DRAWBACKS OF POWDER COATING
- Scratches show contrast between powder coated surface & substrate more noticeable.
- Curing is energy intensive.
- Can show more “orange peel” in surface.
- Powder coating can peel or separate from substrate.