This description applies to untreated aluminium surfaces. The rate at which the original bright metallic appearance will become dull as the surface oxidizes and develops a roughened texture depends upon environmental conditions. Mill finish is not usually suitable where appearance of the glazing system is of importance. This finish would be more suitable for a factory roof rather than a feature canopy.
(b) Powder Coating
This process begins with the mill finish material being pre-treated
in tanks of acid to clean the outside faces thoroughly. The aluminium is
then spray coated with a polyester based powder, which is stoved on to produce
a protective film. An extensive range of colours is available as standard
and many non-standard or metallic finishes are available at a surcharge.
All Powder coating by the Standard Patent Glazing Company conforms to BS
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Suitably prepared aluminium is treated electrochemically during which process the surface of the metal is converted to a hard, translucent film of aluminium oxide forming a protective coating. A small range of colours are available as standard.
The appearance of the anodic film depends upon material composition, form, temper or condition and surface texture and care should be taken in the selection of materials for components that are required to be closely matched. Different extruded sections and sheet materials can give different shading results, and for this reason, powder coating will give a more consistent finish. All anodic oxide coating by the Standard Patent Glazing Company conforms to BS 3987.