Powder Coating

Powder coating is a fine dry powder coating material used for prepping, painting, and protecting a wide range of industrial, commercial, and consumer products. Powder coating is typically applied electrostatically using a powder coat gun or industrial powder coat nozzle. Powder Coating is fast becoming the preferred finish for many product applications because they are versatile and environmentally friendly.   Once applied, the coating is heated to flow and cure to a hard durable finish. This curing process requires a certain temperature for a certain length of time in order to reach the full cure and establish the full film properties for which the material was designed (typically 200°C (390°F) for 10 minutes).

Nortek provides the specific application and cures specifications that are optimum for each product that is manufactured. Powder coatings can be formulated in a wide range of colors, glosses, and textures. Powder coating differs from conventional liquid paint in that powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. Powder coating provides a hard finish that is tougher than conventional paint.


Advantages of Powder Coating


Some other noteworthy advantages of powder coating include:

  • It’s Clean – Near Zero Volatile Organic Compounds (VOC)
  • It’s Recyclable – Overspray is recyclable enabling nearly 100% use of the coating product
  • It’s Economical – Lower capital and operational cost than conventional liquid coatings
  • It looks Great – Better finish uniformity than liquid coatings  


How is it Applied?


The most common way of applying the powder coating to metal objects is to spray the powder using an electrostatic gun, or corona gun. The gun imparts a positive electric charge on the powder, which is then sprayed at approximately a high speed towards the grounded object by mechanical or compressed air spraying and then accelerated toward the workpiece by the powerful electrostatic charge. A wide variety of spray nozzles are available for use in electrostatic coating. The type of nozzle used will depend on the shape of the workpiece to be painted and the consistency of the paint. The object is then heated, and the powder melts into a uniform film and is then cooled to form a hard coating. It is also common to heat the metal first and then spray the powder onto the hot substrate to achieve a more uniform finish but can also create other problems, such as runs caused by excess powder. Another type of gun is called a tribo gun, which charges the powder by (tribo electric) friction. With a tribo gun, the powder picks up a positive charge while rubbing along the wall of a Teflon tube inside the barrel of the gun. These charged powder particles then adhere to the grounded substrate. Using a tribo gun requires a different formulation of powder than a corona. It is also possible to apply powder coatings using a dipping process. The Powder Slurry process combines the advantages of powder coatings and liquid coatings by dispersing very fine powders of 1–5 micrometer particle size into the water, which then allows very smooth, low film thickness coatings to be produced. 


Typical Product Applications

Powder coating is used in a wide range of product applications including residential and commercial construction, transportation, heavy equipment, recreational equipment, and medical equipment. Some specific examples include consumer and commercial appliances, agricultural equipment, architectural components, automotive components and body parts, bicycle and motorcycle parts, computer and electronic components and casework, fitness and exercise equipment, highway and public park signage, office furniture, outdoor furniture, plumbing and electrical fixtures, Powder coating has traditionally been used for coating metals, however recent advances have been made which allow many other materials to be powder coated including whiteboards, as a low-cost replacement for ceramic coatings.  If you are considering powder coatings for your requirement contact Nortek for fast, personalized service.




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