Powder coating is a type of dry coating, which is applied as a free-flowing, dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a “skin.” It is usually used to create a hard finish that is tougher than conventional paint. Powder coated surfaces are more resistant to chipping, scratching and wearing than other finishes. Powder coating is mainly used for coating of metals, such as “white goods”, architectural aluminium extrusions, automobile, truck and motorcycle parts. Dura Industries has certifications for PACCAR CMT0030 AND CMT0048 and they are approved applicators of PVDF Kynar 500® powder coatings.
They have a conveyorized system to handle large volume jobs and a batch booth for the day to day small jobs. Advantages and disadvantages of powder coating.
Advantages of Powder Coating
- Powder coatings emit zero or near zero volatile organic compounds (VOC).
- Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging.
- Powder coating production lines produce less hazardous waste than conventional liquid coatings.
- A wide range of specialty effects is easily accomplished which would be impossible to achieve with other coating processes.
- A significant disadvantage is touching up small damaged places. In many cases the parts have to be re-coated.
- Virtually unlimited color selection with high and low gloss, metallic and clear finishes available. Texture selections range from smooth surfaces to wrinkled or a matte finish, and rough textures designed for hiding surface imperfections.
Paint and powder coating systems are designed to be applied over clean metal that has been properly pretreated. All materials that come into the shop are counted and inspected before they go into the pretreatment system. Aluminum goes through a 7 stage Chromium Chromate conversion process meeting the rigid requirements necessary to meet coating specifications for PACCAR truck parts and Kynar 500® aluminum coatings for architecture which, in summary, consists of:
Stage 1 – High temperature alkaline wash
Stage 2 – Ambient rinse
Stage 3 – Deoxidizer acid etch
Stage 4 – Ambient rinse
Stage 5 – Chromium Chromate conversion coat
Stage 6 – Ambient rinse
Stage 7 – Ambient rinse & dry off
The pretreatment tanks are checked daily and maintained regularly to assure that the solutions and temperatures are at optimum conditions.
In 2006 Dura Industries installed equipment to evaporate wastewater that, for many years, was being discharged into the local sewage system. Today all waste water is evaporated and the volume of water usage has dropped to less than 1/4 of previous usage. Hazardous waste that is hauled to designated landfills has also dropped by more than 60%.
Kynar® and Kynar 500® are registered trademarks belonging to Arkema Inc.