Aluminium metal naturally protects itself by immediately forming a protective layer whenever the surface is damaged. Anodising provides much thicker protective layers than those that occur naturally.

Anodising provides a strongly abrasion and corrosion resistant surface suitable for both commercial and domestic joinery.

Anodising Process

The anodising process is where a controlled electrical current is passed through extruded aluminium profiles immersed in a sulphuric acidic solution. This forms a protective film of aluminium oxide on the surface of the aluminium.

Anodising is an induced thickening of the natural protective oxide film on the metal’s surface; converting the parent metal rather than applying a coating to it. This provides a proven, very durable finish. The lifetime is dependent on the density, thickness and seal quality of the anodic film.

Sealing and Coloring

To complete the Anodising Process the oxide film can be retained in its clear, natural state, or coloured by using various colouring methods.

Conventional sulphuric acid films are microscopically porous absorbingiInorganic compounds to produce a range of colours.

This film consists of many small pores that can be used to colour the aluminium during the anodising process. The small pores are then sealed to permanently lock in any colour added.

The Anodised Finish

The oxide film provides a hard, durable, weather resistant surface finish, protecting the underlying base metal. Unless the finished product is subjected to forces that cause severe deformity or stressed by excessive thermal movement, the anodic film will remain undamaged - it will not not chip, peel, or crack.

The electrochemical process causes the film to actually integrate with the base aluminium metal, becoming part of the structure.

These durable anodic films are particularly suitable for regions with high ultraviolet and coastal environments such as New Zealand.

Benefits of Anodising

Anodising provides:

Favorable life cycle costs compare with other finishes.
Anodising produces an even film thickness, including around sharp edges.
Because Anodising is an integral part of the aluminium surface it will not flake or chip off.
Deep lustrous metallic finishes
A choice of gloss levels ranging from deep matt finishes to bright polished finishes
A wide selection of colours, many suitable for exterior use. The recommended exterior colours are seldom affected by ultraviolet radiation from sunlight even when shaded walls are compared with those in full sunshine exposure.

Durability

The durability of anodised joinery is from theiIncreased thickness of anodic films.

Film thickness impacts not only appearance, but also environmental and maintenance requirements. The denser the film, the longer it will last.

The thickness of the coating is determined by the time the product spends in the anodising tank. For instance, a thickness of 25 micron takes twice as long to process as 12 micron.

Pricing

The price of Anodising is determined by:

Thickness of the coating - depends on the corrosion protection required. In non aggressive environments 12 micron maybe adequate, however as the environment becomes more aggressive a thicker coat of 20 or 25 microns is required. Cheap options using thinner films may result a finish that show erosion, pitting and staining within a few years.
Colour of the anodising - The natural colour of anodising is silver. Coloring takes 3 more processing steps for most shades. The additional cost comes from the extra processing time and the addition of chemicals for colouring.

Maintenance and Care

Regular cleaning is required, the frequency depending on accessibility and the severity of the environment:

Rural environments - where grime deposition and pollution of the atmosphere are minimal - cleaning may only be required every six months to remove deposits and restore the appearance. Use clean water with a mild detergent. Any tough stains can be removed with a mild-moderate household liquid abrasive. This action may remove a small amount of the anodic layer, which leaves behind a renewed anodised finish. DO NOT use of harsh abrasives - this will damage the film.

Finish by thoroughly rinsing the entire area with large quantities of clean water. Pay particular attention to flushing debris and residues from crevices, joints and drain holes

Do Not Use:

Emery paper, sand paper, steel wool or other highly abrasive materials.
Acid or alkaline cleaners
Emulsion cleaners, proprietary chemical agents and solvents - these may also attack the anodised coating or surrounding window components