Powder coating is exactly that. Powder pigment is electrostatically charged as it is ejected from the spray gun using low pressure air. The powder particles then deposit on the oppositely charged part, evenly coating it. Once coated the part is placed into an oven at 400° F for 10 minutes which melts the powder allowing it to flow like paint and then cures the coating. When removed from the oven the part is allowed to cool and ready to ship.
Powder coating requires the part surface to be clean and when possible clean, bare metal to ensure a good electrical path. Part preparation requires removal of rust, paint, and other contaminants through stripping or media blasting. Final preparation is a wash stage to remove blasting dust and oils/solvents.
Powder coating has several advantages over paint:
- Powder coating does not require liquid solvents for pigment suspension – safer and more environmentally friendly
- Powder coating provides much thicker coatings than painting – incredible durability, scratch resistance, and metal protection
- Powder coating produces little hazardous waste, unlike painting or plating
- Metallics, pearls, primers and clear coats available, just as for paint
- Unlike paint powder coating can provide many types of texturing effects:
- Powder coating’s texture and thickness can conceal many minor flaws in the part surface, allowing less part preparation after fabrication to achieve a high quality finish
Powder coating disadvantages:
- Can only be applied to materials that can take an electric charge – primarily metals, but new technology allows the coating of some wood and plastics
- Can’t be buffed or polished after curing
- Contains some texture or “orange peel” on large flat surfaces – new technology powders are improving this