Powder coating is a process in which a film of decorative powder is laid on the aluminum surface to color it and protect it from external factors. The powder coating process is widely used for coating various metals in domestic and commercial applications. In construction, the global Qualicoat ‘quality label’ is the number one choice for specifiers.
QUALICOAT is a global label and ’not for profit’ association. Qualicoat system verifies the quality of the powder coating materials and processes of its members. Established for 20 years and accepted in 20 countries, Qualicoat is an international benchmark for quality.
For more information about Qualicoat, please visit its official website: www.qualicoat.net
Classes of coatings
There are various classes of coatings defined within the Qualicoat Specification dependent on the excepted longevity.
Powders for architectural coatings fall into three basic classes:
- Class 1 - 1 year Florida - weather exposure - standard
- Class 2 - 3 years Florida - weather exposure
- Class 3 - 10 years Florida - weather exposure
Class 1 powder coating
- Class 1 offers an economic way to provide excellent service life to powder coated aluminium. It is the most common used and offers the standard commercial guarantee. This warranty varies upon whether the shade is satin, matt or gloss.
- In class 1 the samples tested must retain at least 50% of its original gloss level at the end of the test,
- After 12 months less than 50% loss of gloss, and colour change between 2 and 6 delta units (subject to the colour)
- • This pass criterion is commonly known as ‘1 year Florida’
- one-year ‘Florida’ weather exposure category;
Class 2 powders
- Qualicoat Class 2 powders also known as Super Durable powders. The Super Durable powder is 50% more durable than standard powder coating (Class 1).
- After 12 months, less than 25% loss of gloss
- After 24 months, less than 33% loss of gloss
- After 36 months, less than 50% loss of gloss
- After 3 years colour change 2 to 6 delta units, dependent on colour
- This testing criterion is commonly known as ‘3 year Florida’
Class 3 powders
- After 10 years, up to 50% loss of gloss – or commonly known as ’10 year Florida’
Qualicoat launched a ‘seaside’ class of aluminium powder coating in 2008. The standard concentrates on the pre-treatment of aluminium extrusion prior to powder coating and ensures that the aluminium is fully protected against the causes of corrosion.
The standard concentrates on the pre-treatment of aluminium extrusion prior to powder coating and ensures that the aluminium is fully protected against the causes of corrosion.
The pre-treatment consists of a deeper acid or acid and alkaline dual etching of 2 g/m2 (normally just 1 g/m2) followed by a thin conversion layer to completely seal the aluminium surface and to offer a high ‘key’ for the final polyester powder coating.
For the specifier the new optional ‘Seaside’ class offers unparalleled quality which is far in excess of the ‘British Standard’ and ‘European Norm’ 12206-1:2004.
This class is a more intensive pre-treatment and finishing method. The Qualicoat standard includes a seaside class determined as within 5 kilometres from any coastal or tidal estuary.
Seaside Class is recognised by a deeper etching of the aluminium substrate of the aluminium. For standard pretreatment, the total etching is specified as being at least 1.0 g/m2, when ‘Seaside Class’ is specified an enhanced pretreatment etch of at least 2.0 g/m2 is required, that is 2/g/m2 of aluminium surface removed. This deeper etch removes more surface contaminants on the aluminium and offers both better protection of the substrate and key for the powder coating. QUALICOAT coating members offering this enhanced Seaside Class are denoted by the qualification on the QUALICOAT website.
Gloss levels of powder coating
Powder coated colours come in different gloss levels. The term “gloss” refers to the impression of the shininess of a surface. The amount of light reflected from a powder coated surface is its gloss level. The more light a surface reflects, the higher gloss it is. The color in higher gloss level appears brighter and richer than the same color in lower gloss level.
Gloss level affects the perception of the colour chosen for your project. The same color can vary across gloss levels.
|Gloss level key||Gloss level|
|Matte||30% (+⁄-5%)||While it does reflect some of the light, the reflection is faded and not clear-cut.|
|Satin (Semi-gloss)||70% (+⁄-5%)|
|Gloss||80% (+⁄-5%)||A highly reflective smooth surface and more resistant to abrasion when being cleaned|
It is important to highlight that the standards for gloss levels in use are not uniform across all service providers.
Global powder coating providers
Interpon, Syntha Pulvin, Tiger, Axalta and IG Paints.
What to consider when when choosing the powder coating
There are three things to consider when choosing your powder coating properties:
- Gloss level
- Class type