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A History of Powder Coating
Powder coating has replaced liquid coating for metal parts in industrial applications more and more over the past several decades as powder coating has become more durable, more environmentally friendly and less wasteful than liquid coating. Technological advances and innovations in the process continue to expand its versatility and popularity.
Like several innovations that came about around the time of World War II, powder coating can trace its roots back to the late 1940s. Liquid painting involves solvents, which contain pollutants, and create waste. The first form of powder coating to be developed was through flame-spraying powders onto metal. While heat still plays a significant role in powder coating today, it is not through flame spraying. As you can imagine, flame spraying poses a danger to the applicator and those around them.
A fluid bed application became the popular method of powder coating from about 1958-1965. Developed by German doctor Erwin Gemmer, the process called for preheating metal parts before immersing them in a bed of thermoplastic powder. The process was both faster and safer than flame spraying. One disadvantage, however, was it was difficult to control the thickness of the coating.
In the early 1960s, the now-popular electrostatic powder coating process was adopted from the very coating it was trying to replace, liquid coating. In electrostatic powder coating, the powder is charged and the surface being coated is grounded, to create an attraction for the powder. The item being coated is then baked in an oven to cure the coating.
The process of electrostatic coating, or e-coating, allows for spraying on the powder in a more easily controlled thickness. Along with eliminating the need for solvents in the application process that liquid paint typically relies on, spraying on powder coating through e-coating allows for recovery of oversprayed powder, which can then be used again, thus reducing waste in the application process. Powder coating, while usually economical only at an industrial level, is more environmentally friendly than liquid coating. Powder coating also is more resistant to corrosion and chipping than liquid paint coating.
Although there are advances in coating and application of powder coating, e-coating has remained the most popular and common process for powder coating for the past seven decades. In addition to coating metal, powder coating now can be used for plastics, wood, composites, glass and MDF. Microfinish provides expert, professional St. Louis powder coating finishing services for a wide range of parts and industries.
