The Art & Science of Identifying Recycled Timbers - Our Process
July 2024
Recycling demolition timber is a precise and skilled process that we have perfected over many years. From de-nailing and docking to identifying and sorting, each step is essential in preparing the quality recycled hardwood architectural products, joinery & furniture we make at Thor's Hammer. Read on to learn more about our timber recycling and identification process.
Photo: Our recycling manager Matt showing a reference board that shows the categories into which we sort each species. (Photographer: Ellie Keft)
Before any recycled timber can be repurposed, it undergoes a rigorous preparation process; de-nailing, docking, identification and then sorting.
STEP 1: De-Nailing
The first step involves removing nails from the timber—that is, ‘de-nailing’—which is a crucial step to prevent damage to woodworking machinery.
Using specialised tools and techniques honed over 30 years, our team carefully extracts every nail. Depending on the timber and the condition of the nails, we’ll use different techniques to de-nail the timber.
For floorboards, we primarily use a combination of pinch bar, hammer and pliers.
We also use a specialised tool called ‘The Dennis’ (named after one of the guys in our early days who loved using this tool), to enhance efficiency and reduce strain. This tool allows us to pull both nails out of a floorboard in one go, while working in a standing position. Pushing on the long handle tightens the jaws and pulls the nails out at the same time - body weight does all the work.
We use an air-powered gun (for particularly stubborn nails) which shoots nails back through the timber.
When nails are broken off or difficult to pull out by hand, we drill them out. The goal is to remove the nails as cleanly as possible, minimising damage to the timber.
Locating nails, especially those broken off just below the surface, is crucial. We use both high strength magnets and handheld metal detectors (similar to those used in airports).
De-nailing is hard work, and needs to be done by strong, efficient technicians to preserve as much high quality timber as possible.
Waste Not Want Not — What We Do With Extracted Nails
Nothing goes to waste here at Thor’s! While most nails are sent for local steel recycling, a portion are transformed into new one-of-a-kind artworks and products like our Spin Pin brooches (pictured below).
Each brooch showcases recycled nails extracted from demolition timbers in our workshop, the old bent nails are displayed in a twisted curl of stainless steel.
Created by Geoff Farquhar-Still, an Australian public art sculptor and stainless steel fabricator based in Launceston, these pieces are available for purchase in our online store or at our workshop and gallery.
Spin Pins
Spin Pins are part of our Thinking Small collection. The collection showcases small-scale design and extends the life of high quality demolition timber and waste otherwise destined for landfill. Check out the Thinking Small collection here.
SteP 2: Docking
Once de-nailed, the timber is docked. This process involves cutting the ends of the timber to reveal 'unweathered' surfaces that aid in identifying the species. Docking also helps in removing any cracks or damaged portions, ensuring only the best sections are used in further processing (that is, when we turn the timber into flooring, cladding, decking, furniture, or something else)
Docked ends and offcuts are all collected and go into forming our firewood pallets.
Double-checking For Any Missed Nails:
Timbers undergo additional checks during identification and sorting. Using a metal detector adapted from the food industry, we ensure no nails are missed. As the timber runs on rollers through the detector, it sprays a natural beetroot juice based dye on any nails, helping the team quickly locate them.
Photo: The second check for nails. Prior to sorting each timber passes through a customised conveyor and metal detector that sprays the timber with a small squirt of beetroot juice if metal is identified.
Step 3: Identification
With the timber prepped, the next step is identification, where art and science truly intersect.
We carefully examine each piece of timber, paying close attention to colour variations, grain patterns, and texture.
When examining colour, we’re mentally sorting through the huge range of natural colours found in Australian hardwoods, ranging from the yellow of ash, deep reds of bluegum, the varied pinkish hues of brushbox, strong browns blackbutt and clayey browns or ironbark.
Within each of these species there are further natural variations which can vary depending on the past use of the timber.
When examining grain patterns, we are looking for subtle variations and unique features such as the size and arrangement of pores, growth rings, and any specific markings like ray flecks or figure patterns. We’re also looking at the overall density and hardness of the wood.
For example, ironbark is known for its very tight and typically straight grain, occasionally exhibiting interlocked grain whereas the grain of brushbox is variable and often fiddlebacked.
And finally, when we’re examining texture, we’re looking at the surface feel (is it smooth, or coarse?), and are there any raised or sunken sections of grain.
This visual inspection, backed by years of experience, allows us to categorise timber into specific species and species groups like blackbutt/dense browns, ironbark/dense reds, bluegum/coastal reds, mixed ash, brushbox, spotted gum.
Distinguishing between similar species requires a trained eye and deep knowledge of timber characteristics.
Could AI Help With Timber Identification?
At Thor’s Hammer, we’re always exploring ways in which new technologies can make our processes more efficient (without compromising quality and effectiveness).
Our founder, Thor, reckons that one day we’ll be able to use AI to help with timber identification… but it’s a way off at the moment!
“We are always trying to improve our timber identification and in the longer term we think AI may be able to help. There are already AI tools for common timbers used in Europe and the USA (using a magnifying lens attached to a phone camera to identify the timber from the end grain), but the databases only include a few Aussie timbers at this stage. ”
Photo: A board of end grain samples in our workshop assists with identification.
Step 4: Sorting
The final part of this stage in our process involves sorting the pieces of timber into various mixes and packs. This sorting is crucial as it allows the picking team to efficiently locate and select the appropriate timbers for specific products, from flooring, decking and cladding, to furniture, joinery and other projects.
Sorting and storage is an important part of our inventory management system, too. At Thor’s Hammer, the history of each piece of timber is an important part of its appeal. By categorising and cataloguing our loads of timber correctly, we can pass on this story to you when you purchase different types of timber.
It means you’ll not only have a clear understanding of the qualities of the timber, but you’ll have full transparency of where we’ve sourced it from, and the fascinating stories and history of that comes with it!
Image: A diagram showing our recycled timber mixes and sorting process,
While preparing recycled timber for its new life involves substantial effort and specialised techniques, it's a crucial step in the recycling of these valuable historic timbers.
By meticulously de-nailing, docking, identifying, and sorting each piece, we ensure that only the finest Australian hardwoods are ready to be repurposed into bespoke furniture and sustainable construction materials. Our commitment to quality and the preservation of unique timber characteristics drives every aspect of our process
