A new mystery surface treatment developed by the CSIRO is set to enhance the viability and desirability of hardwood components in construction, by improving bond strength when adhesives and coatings are applied. In research funded by FWPA, the patented surface treatment significantly improves strength when bonding hardwoods together using polyurethane adhesives and increases the bonding capacity of timber and clear coatings.
FWPA Research and Development Manager Chris Lafferty, described the results as exciting. “In practice, this treatment will deliver added consistency, stability and reliability of hardwood timber products, particularly in situations where the timber is exposed to changing conditions such as seasonal variations and in species that are notoriously difficult to laminate,” he said.
Explaining some of the practical advantages to industry, Alex Edwards, Associate at engineering firm ARUP and Steering Committee member said: “With hardwood beams generally being stronger than their softwood counterparts, being able to reduce their size and increase their spanning capabilities through stronger adhesive bonding would certainly be of great benefit.
“Additionally, with the natural oil found in timber causing coatings to lift off over time, this treatment could significantly reduce the need for regular reapplication. Reducing the need to re-apply coatings would further increase the desirability of hardwood as a building material of choice.”
The CSIRO patented treatment is applied to the surface of the timber before the application of adhesives or coatings. The team’s rigorous testing, including up to 4,300 hours of exposure in an accelerated weathering laboratory, has shown adhesives form a deeper and stronger bond with the timber, resulting in improved strength, while coatings become substantially more durable, enabling them to withstand conditions such as UV exposure.
During the testing, the bond strength of Victorian Ash, Blackbutt, Spotted Gum, Blue Gum, and Tallow wood showed an improvement in bond strength of up to 100 percent following treatment. The research team declined to reveal what the treatment is made of, and it is too early to say what it would cost in a commercial setting.
The final stage in the three-phase project will include further timber bond strength trials using a range of species to establish the criteria for optimum performance of the treatment on each, and the refining and development of recommendations around the methodology and equipment necessary for successful industrial application.
Source: R&D Works
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