The art of bending wood is the reason why of our blog that connects its identity to bentwood and that believes that the bentwood gave birth to design.
This ancient craft belongs to various arts but it finds maximum expression with a revolutionary technique, still unparalleled today, patented by Michael Thonet.
In 1861 his Viennese company reached perfection. The wood is bent exactly the same way now as it was then. As a perfect mix of craftsmanship and industry.
So let’s debunk the myths about bentwood. Let’s explore together what is the technological process behind the big success of Thonet furniture.
Welcome to the magical world of bentwood design.
Bending: what does it mean?
Bending does not mean creating a curved piece.
After Thonet, bending means creating a curl by folding a single straight solid wood log without joints, connections or overlaps.
It means transforming, for example, something very similar to a broomstick in a Thonet armchair or a sofa armrest.
Yes, a Thonet armrest is more or less a 130 cm piece of beech firstly bent on itself and then towards the opposite direction.
A curved piece of wood, unlike a piece cut from a plank, offers three advantages:
⊗ High resistance: at one both solidity and flexibility. You need to apply weights five or six times higher than normal load if you want to break it. A model No. 14 chair is capable of bearing over 600 kg.
⊗ Material savings: a bent armrest requires a log of about 1 dm, when obtained from solid wood it requires a wood block of 10 dm. The remnants are waste. The ratio is 1 to 10, huge savings.
⊗ Extremely reduced processing times: the Thonet log is turned on a lathe before bending. Everything happens in a few minutes. On the other hand, an armrest obtained from the plank is curved after the cut by hand only: it takes hours.
We are just talking about the armrest, imagine if we consider an entire chair.
Furthermore, seriality also plays its part. Pieces bent inside a mold are all perfectly identical to each other. It is the beginning of big numbers and of design.
How to bend wood
Wood bending is an ancient craft. Ancient Egyptian carts are proof of this art, it’s also always been used in the naval industry, it’s essential for musical instruments manufacturing.
With Thonet style objects, however, bentwood reached an absolutely unsurpassed peak. And this is thanks to an extremely refined technology that we are going soon to see in detail.
In the beginning, the Viennese company started with a sort of multilayer technique, then through lamellar and finally, in the middle of the 19th century, perfected the solid wood bending process.
Thanks to the steam boilers this patented method gives the wood a deformability rate that it does not have in nature. Just a minute or a little more to forcefully bend the log and give it a new shape, forever.
The previous technique worked on the basis of a natural reaction to increase and decrease in humidity. Fire dries the wood and the fibre shrinks. Water moisturizes it and makes it expand.
This method is good for boats and musical instruments where the curvatures are slight arches obtained on relatively small thicknesses, in relation to bend radius.
Some Thonet tables are made with 6 cm bars and in some cases, there are curled pieces turning inwards. A model by Kohn even shows a right angle off! The Thonet technique shows no limits and makes the impossible possible.
What to bend
But what are the right species? What parts of the tree can be used? You can hear and read about everything, starting from the use of branches and fronds from walnut and sequoia woods up to magical liquids baths and exposures to fire-eaters’ flames.
Michael Thonet spent 50 years of his life developing a perfect technique and identifying the ideal properties of the wood to pick for bending.
He made some rare attempts using cherry oak and some elm thin layers with the first chairs produced in the 1830s and 1840s, then identified the red beech as the perfect wood species for bending. In fact, beech’s fibre offers:
⊗ Hardness and compactness: a guarantee of product durability
⊗ Homogeneity and no knurls or large veining: these often determine weak points with different stiffness and therefore the presence of breaking points during the bending process
⊗ Light colour and not so visible veining: this allows you to dye wood and satisfy all tastes
No branches, no fresh-cut wood, no miraculous bath. You only need (at least) 25 years old red beech logs. That is a stable and hard fibre. Well seasoned. So a compact, still and non-spongy wood.
A perfect technique able to turn the log into a curl without trauma, stretching, deformations.
I showed you the main ingredients for the perfect bent beech recipe. Combine them with a new flexible assembly technology, and this is how you can see 150 years old objects living today.
After a careful restoration done with competence and the adequate maintenance of any woven cane, these furniture are exactly as they were a long time ago. Here is the magic of the bentwood.
Even today, it’s an art that guarantees the non-deformability and the endurance of Thonet-style furniture. It is no coincidence that the contract sector has been the springboard for this kind of furniture and the success of this industry. The furnishing of public places, as for example Viennese cafés.
Just like all the arts, bending wood needs practice, some secrets and a lot of experience. And this is the reason why objects mass-produced more than 100 years ago are no longer reproducible to date. It’s a question of raw material, but it’s also a question of great manual skills lost over time.
Now you are ready to try to build your own bentwood chair. I’ll wait for updates from you, comfortably seated on a beautiful Thonet chair bent over a century ago. It could be a very long wait. Meanwhile, I wait for your comments.
If there is any doubt left, no problem. Here is a video about wood bending made by the TON company in its factory located in Bystřice pod Hostýnem, Czech Republic. The beautiful cover pic is also by TON. Today as in the past. Enjoy the video.