An Introduction to Aluminium Powder Coating

About this course.

Powder coating is a finishing process in which a dry powder — made of finely ground pigments and a polymer resin — is applied electrostatically to a metal component and then cured in an oven, where it melts, flows and hardens into a tough, continuous coloured film bonded to the metal; it is used to finish architectural aluminium so widely because it produces a durable, attractive, colour-fast and cost-effective finish with a very wide colour and finish range and with minimal solvents and waste. The short answer is that powder coating gives aluminium the colour, appearance and added protection it needs for building applications, does so more durably and with lower environmental impact than traditional solvent-based liquid paints, and can be produced consistently as a controlled factory process — which is why it dominates the finishing of architectural aluminium in Australia. This module explains what powder coating is and why it suits architectural aluminium, setting up the process, benefits and quality factors that follow.

What powder coating is. Unlike a liquid paint, which carries pigment and resin in a liquid solvent or water that must evaporate, powder coating uses a dry powder with no liquid carrier. The powder is a mixture of a polymer resin, pigments for colour, and additives that control properties such as flow, gloss and durability. It is applied as a dry powder that clings to the metal by electrostatic attraction, and it is then heated in an oven so that it melts, flows out into a smooth layer and, for the thermosetting powders used in architecture, chemically cross-links (cures) into a hard, continuous film. The result is a solid, uniform coating chemically and physically bonded to the metal. Because there is no solvent to evaporate, the film is built in essentially a single application and cure, without the multiple coats and drying that liquid systems often need.