What is Powder Coating?

What is powder coating

Powder Coating is a dry finishing process that has become extremely poplar, and is used on a wide array of products. Powder coating is a process to coat and seal metal parts as an alternative to paints and other coatings.

More and more companies specify powder coatings for a high-quality, durable finish, allowing for maximised production, improved efficiencies, and simplified environmental compliance. Used in functional (protective) and decorative finishes, powder coatings are available in an almost limitless range of colours and textures.

Powder coating is more durable than traditional metal paints and will not chip or flake as easily. It is also much more resistant to corrosion, damage from chemicals and weather, and general wear and tear. Finally, Powder coating is not flammable or carcinogenic, and the whole process is generally less damaging to the environment than paint.

Powder coatings are based on polymer resin systems, combined with curatives, pigments, levelling agents, flow modifiers, and other additives. These ingredients go through a process and ultimate end up as a fine powder, much like talcum powder.

This application method uses a spray gun, which applies an electrostatic charge to the powder particles, which are then attracted to the grounded part. After application of the powder coating, the parts enter a curing oven where, with the addition of heat, the coating chemically reacts to produce long molecular chains, resulting in high cross-link density. These molecular chains are very resistant to breakdown.

The Process

1. Pre-treatment. The item must be thorough cleaned to ensure it is freed by dust, scale, rust, grease, dirt and any oxide layers. This is probably the most important part of the whole process, as unless this step is perfect, the whole process fails.

2. Application. By using a powder spay gun, the powder coating is applied to the grounded surface. It is essential to ensure no contamination. The powder spray gun creates a charged cloud of powder. As a result, the paint particles adhere electrostatically to the piece and form a layer.

3. Curing. The powder coating is then cured in an oven at temperatures between 110 and 250 °C. Various factors such as heating time and substrate thickness affect the final curing time.

Powder Coating and the Environment

Powder coatings do not contain toxic heavy metals, are free of solvents and therefore do not release VOCs (volatile organic compounds) during coating or curing. This is also reflected in the CO₂ footprint, where powder coatings have the lowest values of all available coating solutions.   This means that, unlike solvent-based wet coatings, powder coatings are inherently environmentally friendly and offer the highest quality as well as outstanding performance.