Powder Coating
Powder coating is a type of coating which is applied as a free flowing powder that once heated forms a plastic type ‘skin’ to create a finishing surface.
The coating is typically applied electro statically and is then cured under heat to allow it to flow and form a "skin." The powder may be a thermoplastic or a thermoset polymer. It is usually used to create a hard finish that is tougher than conventional paint.
Powder coating is mainly used for coating of metals, such as "white goods", aluminium extrusions, and automobile and motorcycle parts. Newer technologies allow other materials, such as MDF (medium-density fibreboard), to be powder coated using different methods. Here at Gatewise we mainly use powder coating for metals such as gates, fences and handrails.
A dry powder is applied to the material. It is then heated to form the coating. There are 2 main techniques of powder coating. The first way is to dip the item into a fluid version of the powder then bake in an oven. The second way is to spray a powdered paint that has been electrostatically charged onto the part.
There are 2 main types of powder coating, thermosets and thermoplastics. 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.
With thermoset powder coating, the powder will not melt upon re heating. It undergoes additional reactions with the polymer (a chemical in the powder) improving the performance properties. Thermoplastic powder coating has no additional reactions during heating process, therefore will melt when reheated.
Powder coatings are usually much thicker than conventional liquid coatings and they don’t run or sag. The current Australian Standard thickness is “AS/NZS 4506”. We recommend 25 micron for interior applications and up to 60 microns for exterior applications. However this will depend on the colour and coverage. Whites tend to use more, about 75 microns for full coverage.
Powder coating can be recycled therefore much better for the environment. Powder coating tends to be less expensive than traditional liquid coating and have very few appearance differences between horizontally and vertically coated surfaces.
Powder coatings have longevity when maintained regularly, so long as there are no damages when installed. They should be cleaned regularly with a neutral soap and rinsed with water. The powder coating will not peel, chip or crack as with traditional paints.
