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How Does Powder Coating Work?

Powder coating is commonly used in the manufacture of metal products and fabrications.

Powder coating company

Powder coating is based on the principle that objects with opposite electric charges (positive and negative) attract one another.  Powder particles are negatively charged by passing them through a special spraying gun.  This results in an electric field between the spray gun and the earthed component.  The powder particles then follow the field lines and adhere to the product.

The component is then conveyed to an oven where the powder is baked at temperature of 160 to 200 degrees C for approximately 20 minutes.  Most conducting or thermally stable materials are suitable for powder coating and metals are particularly good due to their high electrical and thermal conductivity.  Complex metal components can be powder coated evenly with excellent adhesion.

Pre-treatment

All products are cleaned and treated prior to powder coating to ensure correct adhesion.  Hydram Sheet Metalwork uses a typical three-stage pre-treatment spray system on its first conveyor line:

  • Stage 1:  Clean and Phosphate (temperature 50 degrees C)
  • Stage 2:  Rinse
  • Stage 3:  Clean water rinse

The second conveyor line (new in 2015) uses a five-stage pre-treatment system using the Oxsilan process from Chemetall:

  • Stage 1:  High alkaline cleaner (temperature 50 degrees C)
  • Stage 2:  Clean water rinse
  • Stage 3:  Demin water rinse
  • Stage 4:  Silane-based, multi-purpose pre-paint treatment
  • Stage 5:  Demineralised clean water rinse

The batch plant uses a five-stage phosphate-based pre-treatment system:

  • Stage 1:  High alkaline cleaner (temperature 50 degrees C)
  • Stage 2:  Clean water rinse
  • Stage 3:  Clean and Phosphate (50 degrees C)
  • Stage 4:  Clean water rinse
  • Stage 5:  Final clean water rinse

Components are then dried at a temperature of between 100 and 120 degrees C before the powder is applied.

Hydram - the precision sheet metal fabrication company.

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