How to apply powder coating for aluminium profiles

Powder coating is an excellent finishing method for aluminum profiles, providing durability, corrosion resistance, and an attractive finish. Below is a detailed step-by-step process for powder coating aluminum profiles, including best practices and key considerations.

1. Pre-Treatment (Surface Preparation)

Proper surface preparation is critical for adhesion and corrosion resistance, in order to remove oils, dirt, and contaminants using an alkaline or acidic cleaner.

• Degreasing: Use a solvent or detergent to eliminate grease.

• Blasting: Lightly abrade the surface to improve adhesion.

• Chemical Conversion Coating: Apply a chromate or phosphate treatment (e.g., Alodine) to enhance corrosion resistance.

• Rinsing: Rinse thoroughly with deionized water to remove residues.

• Drying: Ensure the aluminum is completely dry before coating.

2. Powder Application

• Electrostatic Spray Gun: The most common method, where the powder is charged and adheres to the grounded aluminum profile.

• Color & Type: Choose the right powder (epoxy, polyester, or hybrid) based on durability needs (UV resistance, corrosion protection, etc.).

3. Curing

• Oven Curing: Heat the coated aluminum in an oven at 150–200°C (300–400°F) for 10–20 minutes (varies by powder type).

• Infrared Curing (Faster): Suitable for high-production environments.

4. Cooling & Inspection

• Allow the profiles to cool naturally.

• Check for uniformity, adhesion (cross-hatch test), and defects (orange peel, bubbles).

5. Additional Treatments (Optional)

• Clear Topcoat: For extra UV protection.

• Texture or Matte Finish: Depending on the application.

Key Considerations for Aluminum:

✔ Avoid Overheating (aluminum loses strength at high temps).
✔ Proper Grounding is essential for electrostatic application.
✔ Thickness Control: Typically 50–100 microns for optimal performance.