Powder Coating is the term used to describe a paint finishing used widely on aluminium and metal framing for windows and doors to create a high-quality, durable finish.
The coating is based on a polymer resin solution, combined with curative, pigments, levelling agents, flow modifiers and other additives which are melt-mixed together, cooled and then ground into a powder form.
This powder is applied to the framing surfaces using a process called Electrostatic Spray Deposition (ESD). A spray gun applies an electrostatic charge to the framing to be coated which then attracts the ground powder coating ensuring an even application of colour.
After the powder coat is applied the framing elements are put into a curing oven where the coating chemically reacts, bonding to the framework resulting in a highly durable finish which is highly resistant to UV.
Powder Coating is categorised in standard RAL colours in order to give uniform finishes through different elements and framing.
In addition to powder coating's superior finishes and high durability the process emits near zero volatile organic compounds (VOC's), any overspray can be recycled and powder coating production lines produce less hazardous waste than traditional liquid coatings.
New advances in powder coating mean that it is now possible to achieve all the positive aspects of a powder coated finish in metallic effects, broadening the design appeal of this finishing method.
Powder coating is measured in thicknesses measured in microns. Certain environments and applications require a certain thickness of microns in order to withstand their environment. The British Coatings Federation recommends that coating thicknesses do not exceed 80 microns, as coatings that exceed this thickness have the tendency to exceed their charge potential and fall away from the aluminium. Generally, any projects in a 'Marine Environment' are recommended to be powder coated to a marine grade finish, which is a powder coat at a minimum of 40 microns and 50 microns on average to withstand the corrosive atmosphere and salts in a coastal environment.
An alternative to powder coating is anodising which gives a more metallic finish but has disadvantages in terms of durability against scratches and knocks.