The earliest forms of powder coating have been around since the early 1950s and were born from America’s insatiable appetite for motor vehicles. The continued streamlining of the sub contract supplier network led to manufacturers seeking the “holy grail” of a one coat finishing system. This coupled with early signs from environmental pressure groups led to powder coating as we know today, which can be best described as “solid paint”.
The advantages over the established systems of traditional spray enamelling were of speed of application and the continued pursuit of a high performance coating process. In place of the traditional etch prime, primer and possibly 2 coats of top coat, powder coating can do these all in one operation, there were however limitations.
Some of earliest examples of plastic or powder coating were quite simply of placing the pre – heated component in vat of aerated or fluidised powder. The powder was placed in a container with a fine membrane and a controlled amount of compressed air was passed through this membrane, the powder above then bubbled and subsequently doubled in volume, the heated components were placed in this bubbling liquid for the time determined by the thickness of finish required and the amount of sink the component held, this was powder coating in most simple form and offered little or no performance or aesthetic qualities but it did offer the distinct advantage of speed and in turn cost savings.
The application equipment was developed from dipping in, to the spraying of, powder and the basic spray equipment from the 1960s and 70s has now led us to the state of the art equipment we recognise today, however the same three key parts of the process remain as important now as they were then, these are the pre-treatment, application and curing of the components, these 3 key elements of the process will be discussed in future articles, along with the environmental issues associated with the powder coating industry.