THE HISTORY OF WOOD BENDING
Ancient Egyptians bent wood after heating it by means of steam. The technique of steam bending was continuously developed and reached one of its climaxes before World War I thanks to the Thonet company. With this technique the company produced amongst others the Thonet-chairs, which nowadays are still famous.
The Thonet bending technique involves clamping the steamed piece of wood that is to be bent onto a steel band so that it cannot move in longitudinal direction. Then the wood is bent together with the band. As the piece of wood is clamped, the fibres are not only bent but also compressed and thus a much tighter bending radius can be reached. In addition, after the bending the band can also be used as a mould for drying the bent wood.
Bending by means of steam is a tedious procedure: you need steam machines, bending machines and bending plates and moulds for each piece, in which the bent pieces need to be dried. After the drying the bent blanks are still to be processed and machined.
The Thonet-method demonstrates that compressed wood can be bent much better than wood that is not compressed.
"PATENTED PLIABLE WOOD" – HISTORY AND BENDYWOOD®
This wood is the result of a further development of the above-mentioned knowledge.
In 1917 the Imperial Patent Office in Berlin patented the method of making wood flexible in the long term. A quotation out of the original patent document (translation): "Blocks of wood are first steamed and then, when hot and wet, put into the press, where they are surrounded by a thick cover in order to avoid deformation during the pressing procedure. Finally the punches are moved in grain direction. The wood is then dried and after the cooling and drying it does not go back into its former length anymore. As a result of that it remains permanently flexible". Pliable wood, produced by this patented method, is thus called "patented pliable wood".
Already in the twenties the "Gesellschaft für Holzveredelung mbH" (wood refining company) in Essen produced this pliable wood up to a length of 165 cm on self-developed steam and compressing machines.
The "patented pliable wood" was already generally known back then: this kind of wood was described in detail in the source of supply listing on page 596 in the type book of aircrafts model making, for instance, which was published in 1939 by the publishing house Hermann Beyer in Leipzig. After World War II the production was continued in Selters/Westerwald and the products were sold not only in Germany but also in every accessible export market at that time (Europe, USA, Far East).
In 1990 the company Candidus Prugger became the successor of the wood refining company in Selters: the production plants and the stocks were brought to Bressanone in Italy and the clients all around the world were further supplied without interruption. In the following years the production process was improved and new products and new markets were developed.
BENDYWOOD® TODAY
BENDING WOODEN HANDRAILS
are the new development, and this wood is mainly used for that purpose today.
For this, pliable wood must be jointed in length so that the joints can withstand the stress during bending.
Handrails up to 12.0 meters long can be made in a single piece,meaning that even length-jointed finished profiles can be bent.
See an example of this:
Bendywood handrail 11,7m long in one piece
These handrails are also delivered pre-bent, in boxes usually no larger than 220x220 cm.
The special „spring back“ properties of this wood make this possible.
Bendywood® has been the name of the patented pliable wood since 2003.
The name is protected as a trademark.