What is powder coating, how does it compared to liquid paint and why use it?
Powder coating is a type of dry coating, which is applied as a free, dry flowing powder.
The major difference between this coating and a conventional liquid paint is that the powder coating does not require a solvent to keep the binder and filler parts in the form of a liquid suspension. The coating is applied electrostatically and is then cured under heat to allow it to flow and form a “film.”
This creates a hard finish that is more durable than conventional paint. This type of coating services is mainly used for coating metals such as galvanized steel or aluminium.
The application of the powder is very simple; one should have filtered compressed air, usually between 20-30psi which pushes the powder out of the spray guns after the electrode which gives the powder a positive charge. The piece to be coated is grounded so that the positive powder particles are attracted to it. When the piece is completely covered, it is transferred to the curing oven for the backing process.
Powder Coating Process
Stage 1: Chemical Pretreatment
The Chemical treatment serves to repair the metal surface to receive and allow a good adhesion of the paint and prevent the development of corrosion processes.
Shot blasting the metal surface for the removal of oil, dust, lubricating greases, metal oxides, welding blades, etc., is essential prior to the coating process.
Stage 2: Powder Application Process
The most typical way to apply the coating to metal is to spray the powder using an electrostatic gun. The coating gun transmits a positive electrostatic charge on the powder, which is then sprayed towards the material to be coated, which is earthed. The material is then heated, and the powder melts to form a uniform film and then is cooled to form a hard coating.
Advantages Of Powder Coating
There are various advantages of this type of coating over conventional liquid coatings:
- Eco and Environmentally Friendly; These coatings emit zero or almost zero volatile organic compounds (VOCs) and also the overcoating of the spray powder can be recycled, and thus almost 100% use of the coating can be achieved.
- They can produce coatings much thicker than conventional liquid coatings without running or sagging which guarantees a bright, smooth finish.
- Exceptional resistance to wear and tear, hard, durable and scratch resistant.
- Resistance to high temperatures, acids, and solvents.
- Excellent resistance to hydrolysis, properties are not affected by water and moisture.
- Protection against external UV fading.
Powder coating provides a high-quality finish and is one of the best options for protecting metal roofing. Not only looks great but it lasts a long, long time.