During 35 years as metal finishing experts for the architectural sector, it has been fascinating to be part of the exciting evolution in powder coatings and to witness their growing dominance in architecture and interior design. Today’s architectural powder coatings can bring life to a piece of metal, turning its appearance into wood, stone or decorative and aged metals such as copper and bronze. Powder coaters can certainly claim to be the modern-day alchemists. Moreover, recent advances in powder technology and application now mean that these finishes can play a major part in incorporating environmental sustainability to building projects.
Abundance and recyclability
Using aluminium, or steel in preference to more scarce materials is significant in an era fully aware of the need to protect natural resources. Aluminium is the most abundant metal in the earth’s crust, and iron (used to make steel) follows closely behind. Both metals are highly recyclable; 75% of aluminium in use today has been recycled. For architectural applications, aluminium has a huge range of advantages over other materials. It has an exceptional strength-to-weight ratio and can achieve long spans leading to fewer fittings and faster installation. It is ductile and can, therefore, be formed into complex shapes and profiles. The products can be flat, curved, perforated, expanded or sandwiched with other materials. Not least of its advantageous properties is its light weight, making it an easy material to work with and transport.
Powders are ‘greener’ than you might think
Powder coating has no effect on the recyclability of aluminium or steel and has, itself, clear environmental advantages over wet paints and liquid wood treatments by being a dry powder, with no solvent, and, therefore, emitting no volatile organic compounds (VOCs). Powders contain no halogens or heavy metals, and there is no hazardous waste. The coating process is a factory-controlled application taking place in a sealed booth and excess powder is collected and re-used so waste is minimised.
Where wood, stone and decorative metals have been the materials of choice, in most cases, it is the appearance of these materials that is desired, rather than their inherent properties. Lightweight, strong and recyclable aluminium when powder coated can resemble these natural materials and satisfy the aesthetic requirement through using architectural powder coatings as credible alternatives to natural or scarce materials such as stone, wood, terracotta, copper and bronze and to the processes of anodising and Corten steel.
Saving trees and increasing CO2 absorption
A wood-finish powder coating on aluminium or steel has considerable benefits over the ‘real thing’ with greater strength so that long sections can be used with fewer fittings and quicker installation. Wood on a building looks attractive when clean, free from lichen, mildew and general staining but needs long-term maintenance routine to keep it looking that way. Powder coatings, on the other hand, need minimal maintenance with no varnishes or special treatments and will not rot, warp or develop mildew. Powdertech Wood Finish has been tested and conforms to fire reaction rating A2-s1,d0 making it far safer than wood. Critically, we need living trees to help combat global warming.
No staining from or leeching of harmful chemicals
The anodising process uses acids, dyes and rare metals to create different colours, and the waste products can be detrimental to the environment. Similarly, the natural appearance of rusted steel has been popularised by the product Corten, but the rusty surface still leeches colour and can stain surrounding materials and potentially affect groundwater. A powder coating emulating anodised aluminium or rusted steel will not leech colour. Furthermore, powder coating provides colour consistency between panels and does not require expensive grade aluminium, as used for anodising.
Stone and terracotta used for building looks magnificent and prestigious, but a rigorous maintenance routine will be needed to keep it looking at its best. Products to prevent lichen and mildew are not generally environmentally-friendly whereas powder coatings need only a quick wash over with water and a basic detergent to remove and prevent staining. Terracotta is porous, heavy, has a poor resistance to tension and can fail due to weathering, atmospheric pollution that causes salt formation and the cycles of freeze-thaw. Powder-coated aluminium suffers none of these issues.
Preserving decorative metals
Decorative and patinated metals such as copper, bronze, gold and silver are far less abundant than aluminium and, therefore, more expensive. Nowadays, designers consider whether these rarer materials should be used at all when there are impressive alternatives. Aluminium and steel will always be preferable as building materials, and if their appearance can achieve the desired effect through powder coating, then the benefits are multifaceted – a ‘win-win’ situation.
Consistency within powder batches is a known benefit of powder coating, especially for modular builds, allowing the colour to be consistent across the development. Where variation in shade and tone is needed, reflecting that found natural materials, powder coating again meets this need to give a ‘consistent inconsistency’, achieving a realistic overall impression.
Powder coatings can impart many different appearances to aluminium, allowing architects and designers to introduce the appearance of stunning, natural materials into their projects without raising environmental concerns. At Powdertech, we aim to support these endeavours by making available a continually evolving selection of powder coating shades and textures through our Collections range which includes stone and wood finishes and the beautiful representations of weathered and patinated metal.