Are powder coatings considering environmentally friendly?

Everything is relative, and powder coatings are considered far more environmentally friendly than wet paints or anodising. Powder coatings use no solvents that are harmful to the environment. Over sprayed powder can be recovered, sieved and then reapplied to other products which helps reduce waste powder.

Powder coatings have limited to no leaching effect in dry form and no leaching effect in the cured form. Given the very good durability of powder coatings, the need to recoat is also less common, meaning less burden on the environment into the future.

How are powder coatings manufactured?

Powder Coatings are produced by dry blending of resins, pigments, additives and curing agents, which are then extruded at elevated temperatures to melt and mix the ingredients. The material then becomes thick and viscous like a honey mixture which is cooled using super chilled water, before the material is crushed progressively to a fine, well defined particle size.

Specialised equipment including rotary sieves and particle size measuring equipment is used to monitor and control the particle size distribution.

Is it true that powder coatings can withstand any conditions and can even be applied to rusty metal?

Unfortunately there is a myth that since powder coating is so much easier to apply than wet paints, and retains a very hard film, that powder coatings can withstand anything and everything. Indeed this carefree view has led to some disappointing applications of powder coatings.

Powder coatings rely on a clean, pre-treated surface like any and every other coating. Rusty metal deposits must be removed prior to powder coating, as over coating with powder will only mask what is fundamentally corroding metal.

Powder coatings are terrific in resisting knocks and abrasions, chemicals and the effects of the sun, but if not cared for, the coating can show up scratches and perhaps film integrity loss.

How long do powder coatings last?

From the perspective of adhesion and film integrity, correctly applied and pre-treated powder coated metal can last more than 40 years.

Powder coatings are extremely resilient, whether they’re applied on gas or oil pipelines that are buried in the earth or underwater. Powder coatings are also used on automotive and appliances given their excellent chip resistance, hardness and or chemical resistance.

From the perspective of resistance to light and UV degradation, some powder coatings are outstanding.

The standard and most common powder coatings are designed for general use and applications. Standard powder coatings offer good weathering resistance, excellent film integrity and very good hardness.

Can I match a powder coating to a paint colour?

Unlike paints that can be tinted to thousands of shades and finishes, powder coatings are formulated and produced in a factory. Powder coatings cannot be tinted successfully since the solid particles of each colour do not blend together, causing a mottled, speckled look when two different colours are mixed together.

What considerations should I make when choosing a colour? Are there good and bad colour selections?

Not all colours behave the same during application or performance on site. In general, light colours are ideal for more applications than other colour groups.

Light colours absorb little light because the white pigments help reflect the light. This reduces the heat up effect on parts. Dark colours absorb light and hence heat far more readily, which explains why dark cars are hotter than white cars in the sun. If heat is an important element in the design or use of your product, the effects of light and dark colours is important consideration.

Bright colours behave differently again. Bright colours not only absorb light and remit this as brightness, but the pigments are more readily damaged by the ultra violet light reducing the life of the colour as we know that colour. Bright colours, which include, reds, oranges, yellows, bright greens and blues are recommended for applications where colour retention is not critical such as playgrounds and furniture.

It is possible to get very good durability out of bright colours, but the very high expense of these pigments limits the use of these products to automotive applications.

How do I maintain and refurbish a powder coated surface?

The effects of pollution, dirt, grime and salt deposits can all accumulate on a powder coated surface over time. To extend the effective life of powder coatings, a simple regular maintenance program should be implemented for the removal of residues.

As a general rule, all powder coated surfaces should be cleaned every six months. However, in areas where pollutants are more prevalent, especially in coastal or industrial regions, a cleaning program should be carried out on a more frequent basis.

To clean a powder coated surface, you should carefully remove any loose deposits with a wet sponge and then use a soft, non-abrasive brush or cloth in combination with a mild household detergent solution to remove dust, salt and other residues. Finally rinse all powder coated surfaces with clean water.

Can powder coatings be applied straight on to metals/substrates?

Whilst powder coatings generally require no primers, it is important to provide a clean and pre-treated surface for the powder coating to adhere to. Metals that are planned for internal location can escape the need for pre-treatment; however it is advisable to provide some metal pre-treatment such as a phosphate finish to steel or chromate finish to aluminium to ensure maximum performance of the finish.

Can powder coatings be applied on site?

Powder Coatings are a factory applied finish using specialised equipment. The equipment includes an electrostatic spray gun, spray booth and an oven to bake (or cure) the coating. On site application is not possible given the hot curing cycle required to fuse the coating.

How many coats are applied with powder coating?

Powder coatings are generally a one-coat finish, applied to suitable cleaned and pre-treated substrates. Some coatings, such as metallics, require a clear coat to protect the metallic effect.