Aluminium substrate-based woodgrain finishes give the look of timber without the maintenance requirements and costs. This benefit is driving an explosion in the popularity of woodgrain finishes in all manner of exterior and interior architecture.
Simply put, powder coating creates a far more stable and durable protective finish than natural timber coated in various wet finishes. In many situations, particularly when there’s more than an arm’s length of viewing distance from the surface, most observers would be hard-pressed to tell the difference. As we’ve already observed, the numbers have it – woodgrain-finished aluminium is on the rise.
Yet, not all aluminium woodgrain finishes are the same. The options are the sublimation process and Powder on Powder (POP). When comparing these two alternatives, one of the most significant differences is the grain patterns’ resistance to UV fading. The difference in the serviceable design life can be more than four times greater in high UV exposure situations such as fencing, louvres and external cladding that are directly exposed to sunlight.
Sublimation process woodgrain finishes have existed for several years.
The sublimation woodgrain finish technology involves several steps. First, the metal substrate is powder coated using electrostatic guns and undergoes an initial heat-curing known as the green-cure process. The object to be decorated is then wrapped with a heat-transfer film printed with a decorative pattern. This film is vacuum sealed to the surface and placed inside an oven where, through heat and pressure, the inks printed on the film are transferred into the coating layer – the final cure. The object is removed from the oven, and the exhausted film is removed to reveal the decorative grain pattern.
Powder-on-powder woodgrain aluminium technology starts out in much the same way, with a base coat of powder coating applied to the aluminium substrate and partially cured. The next part of the process is entirely different from sublimation. The grain pattern is applied with a second layer of powder coating before a final heat cure is performed. This means that both the base colour and the grain pattern are made from the same power formulation.
Australian Aluminium Finishing’s (AAF) Evergrain® process applies the grain layer using a belt system, an Italian-developed technology. Evergrain® also stands apart in having developed dual-layer powder formulations with DULUX. Evergrain® employs only DULUX super durable architectural-grade powders.
The results are guaranteed for up to 25 years; most significantly, colour integrity is warranted for 20 years. The solution is made in Australia for Australian conditions and differs from the imported films used in sublimation.
Sublimation delivers an attractive, sharply defined grain pattern and surface integrity equivalent to the base-layer powder coat. However, it is highly susceptible to ‘differential fading’, meaning the grain coat will fade much faster than the powder-coated base layer. In very high UV environments such as fencing, louvres, or exterior cladding, the grain pattern can begin to fade after only a few years. Still, the definition of the grain pattern makes sublimation a good choice for indoor use when the viewing distance is close.
POP has a distinct advantage in exterior durability, mostly in applications directly exposed to sunlight. The powder layers are bonded together during the curing process, and their identical chemical formulation frees them from differential fading. The AAF Evergrain® process delivers a finished guaranteed 25 years—25 years for surface integrity and 20 years for colour integrity.
Another advantage of the AAF Evergrain® process is that the grain layer creates a texture that adds authenticity to the finish's look and feel.
To our knowledge, no data is available to directly compare the carbon and other environmental impacts of Sublimation vs. POP. On the surface, both finishes are likely to perform similarly from a CO2 perspective in manufacturing. However, when whole-of-life performance is factored in, the longer-lasting performance of POP in direct sunlight will bring significant advantages.
A further difference is the significant quantity of waste produced by the sublimation process. The ink substrate requires disposal after sublimation.
While sublimation has been bringing woodgrain aluminium to architectural applications for several years, it’s meeting a genuine challenge from POP technology. POP brings a significant performance advantage in any situation where the finish is exposed to direct sunlight. The bottom line is a substantial difference in the life of the woodgrain pattern.
Find out more about the Evergrain® woodgrain finish. Lasts longer in the Aussie sun.
Australian Aluminium Finishing (AAF) is Australia’s largest independent aluminium finisher. We operate three plants in Sydney, Melbourne, and Brisbane. Incorporating 11 production facilities that provide the highest quality anodising, woodgrain, and powder coating finishes for architectural aluminium throughout Australia and Southeast Asia.
With a rich history spanning nearly fifty years, AAF was established with a clear vision of specialisation and excellence in surface finishing. This unwavering vision continues to be the cornerstone of our operations.
Today, AAF is regarded as the expert in aluminium finishing throughout Australia.
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