Glazing Technologies

Why not Anodised?

What is an Anodised finish?

When using aluminium framing there are a number of colour finishes available to use depending on the design and aesthetic of your building.

An anodised finish is one such option for colouring the external faces of aluminium frames. The process forms a layer of aluminium oxide on the external faces of the aluminium frame. The visual effect is a metallic external frame colour which can create a very attractive finish, however anodising aluminium has some well-known and documented issues when used on external faces of a building so should be specified sparingly and in consultation with your architectural glazier.

The process of an anodised finish involves a chemical process of passing electrodes from an anode (the aluminium) to a cathode through water. This creates a build-up of oxygen on the surface of the aluminium which reacts and chemically bonds to the aluminium forming a layer of aluminium oxide on the aluminium frame.

To achieve different metallic colours from an anodised frame changes are made to the chemicals in the anodising process. This can then result in anodised finishes ranging from metallic silver to bronze.

What are the issues with an Anodised Finish?

Due to the anodising process being is a chemical process ( rather than a controlled process such as powder coating) it is impossible to guarantee a perfect match between multiple elements of framing and ironmongery. The colour obtained in the anodising process depends on many factors, such as the alloy, temperature, and shape; therefore, it is impossible to produce a perfect colour match across multiple elements.

When anodising the frame 'finish' actually becomes an integral part of the aluminium; therefore any heavy die lines, dents or imperfections on the surface of the raw aluminium section will show through the finish.

When using an anodised finish you have to keep in mind that the colouration is a chemical compound electrically bonded to the aluminium frame. That means that if the anodised finish is scratched it is impossible to retouch or fix.

Powder Coating as an Alternative to Anodising

If you were to powder coat a frame in any RAL colour it is possible to get a colour cover of the same RAL reference to fix any scratches that might occur. In addition IQ can offer a range of powder coated finishes that offer a metallic finish like anodising, but without the inherent draw backs as detailed above.

Contact IQ about our range of anodised look powder coated finishes and if they would be suitable for your project.