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Powder Coating Explained
What is powder coating?
The main difference between conventional painting and powder coating is that powder coating does not require any solvent. The paint is not liquid. Instead, a free-flowing dry powder is used.
The powder is first applied using an electrostatic process. Then the part is heated to make the powder flow and create a uniform coating.
Powder coating is mainly used for coating of metals, e.g. steel and aluminum, and is widely chosen for automobiles, motorcycles and bicycle parts.
Powder coating creates a hard finish that is tougher than that resulting from liquid coatings and produces thicker coatings without running or sagging. Also, some effects which are hard or even impossible to achieve with regular coating processes are easily accomplished with powder coating.
The powder coating process
(involving three basic steps)
  • Preparing the part for powder coating
    • The part to be powder coated needs to be free of oil, grease, dirt, metal oxides, welding scales and other contaminants. It can be cleaned chemically by either submersing the part or spraying it with a solution, or mechanically by sandblasting or similar abrasive methods.
  • Applying the powder
    • When the part has been cleaned, the powder coating is applied using an
    electrostatic spray gun. The gun gives the powder a positive charge, which
    accellerates it to the grounded metal part and makes it cling to it.
  • Curing the powder coat
    • After spraying, the part is heated for a few minutes in a convection or infrared
    cure oven to melt the powder into a uniform film, and then cooled to harden the coat.
    Environmental advantages of powder coating
    The powder coating process is easy on the environment, because powder coatings emit none or only very few volatile organic compounds and produce less hazardous waste. Unlike liquid paint, the overspray in the powder coating process can be reclaimed and used again.