A new way to paint timber
The CSIRO has developed a new powder-coating technique to protect timber products for longer and maintain their aesthetic appearance. Dimi Kyriakou reports.
When it comes to timber products, it is quite common to see them deteriorate and lose colour within a few years. As today’s society becomes more time-poor, people would rather avoid having to repaint or even replace timber around their home on a regular basis.
Given this, it’s really no surprise that low or zero-maintenance alternatives such as metal, plastic and wood-plastic composites are starting to erode timber’s traditional markets in cladding, windows and door products. It is for this reason that the CSIRO has developed a new zero-waste powder coating technology that aims to maintain the quality and aesthetic appearance of timber products, as well as other non-conductive materials.
According to chief research scientist Voytek Gutowski, powder-coated wood finish has proven to be far more durable than a liquid finish. He says this type of technology is projected to grow rapidly over the next five years.
“Virtually everything in and around a home has to have the proper appearance and as a result, timber, plastics or metals have to be painted to give them a nice decorative finish. It’s also important to ensure they don’t deteriorate too fast,” he says.
“Powder-coated timber will combine wood’s traditional appeal and intrinsic environmental advantages with superior toughness and excellent resistance to UV and moisture penetration. It’s a brilliant product concept that means little or no maintenance.”
Powder coating is a dry surface finishing process in which electrostatically-charged fine particles are sprayed onto an electrically-conductive surface. The key to the new wood-coating process will be to make the timber surface electrically conductive so it can attract and bond the powder coating to the product surface.
“When you are spraying paint onto a product, often a very small percentage of paint ends up on the product. We have managed to devise a technique that makes the surface of plastic or wood electro-conductive so when you apply a powder-like coating on the surface, it can be deposited at a much greater efficiency,” he explains.
“It’s virtually a technology that can apply and dry paint without any waste. It doesn’t contain any solvents so there are no Volatile Organic Compounds (VOCs) going into the atmosphere either.”
As Voytek explains, the ‘icing on the cake’ will be the availability of different colours and surface finishes to further stimulate demand from designers, architects, builders and home owners.
“In terms of the practical aspects, this technology is harder-wearing than liquid paint so it’s more difficult to scratch. It’s also got very good adhesion and fades much slower than wet paints under the Australian sunshine.”
So far the technology has been tested on similarly challenging, non-conductive surfaces such as automotive plastics. The team at CSIRO are using Australian, American and New Zealand Standards on the long-term durability of paints on metallic products as a benchmark for testing the performance of powder coatings on solid wood samples.
“We have passed those requirements, so we know how the technology works. Now we need to scale it up and test it on larger pieces of timber and on real commercial products made of commonly-used timber species such as radiata pine and Victorian ash.”
While the technology is still under development, Voytek says the growing interest from research bodies and commercial companies means that builders can expect to see this product hit the market within the next two years.
“It’s a very cost-effective technology that builders could use as a very good marketing tool. If a product is powder-coated with this material in a factory, builders will know that it will be likely to last without the need for repainting in excess of 10-15 years.
“We anticipate that the new technology developed through this project will transform high-maintenance, low-value wood products into low-maintenance, high-tech products.”