Finishes
Powder coating
Powder coating is a dry polymer powder sprayed electrostatically onto metal, then cured in an oven to form a hard, even film. It is the usual colour finish for aluminium shopfronts. BS EN 12206-1 covers architectural aluminium coatings, and Qualicoat is a quality label for coaters.
Where does it work well?
New aluminium and steel frames, door sections, cladding and shutters that need a durable colour finish, and existing parts that can be taken off the building and sent to a coating plant.
Pros
- Hard, even finish
- Wide RAL colour choice
- No wet paint on site
- Stands up well to weather and cleaning
Cons
- Cannot be done on site
- Scratches need a different touch-up paint
- Poor pre-treatment can lead to corrosion under the film
How long does it last?
Typically decades when pre-treatment is sound and the frame is washed regularly, less in salty or polluted air.
What should you check when buying?
Ask what pre-treatment is used and the dry film thickness, and on exposed sites ask about a marine-grade pre-treatment. State the RAL number and gloss level. If you want a Qualicoat finish, ask the coater to show a current licence.
Common questions
Is powder coating stronger than paint?
On new frames, usually yes, as an oven-cured film is harder and more even than a typical site-applied paint. It needs a coating plant though, so paint is the practical choice for fixed frames that cannot come off.
How do I clean a powder-coated frame?
Use water and a mild detergent with a soft cloth, then rinse. Avoid abrasive pads and solvents. Regular washing removes salt and traffic film, and coaters' warranties often depend on a cleaning routine, so check yours.