frederic rätsch x DuPont shape the double cantilever chair as a flexible public seating

industrial designer frederic julian rätsch and specialist for performance materials DuPont™ reveal the double cantilever chair, as part of the project ‘flexible sitting in public spaces’ which begun in october 2016. it was initiated as the graduation project of rätsch for his master’s degree in design products at the royal college of art in london. 

double cantilever chair (DCC) in the tate modern

frederic rätsch‘s  goal was to create a chair for public spaces, and the contract market, that uses high performance qualities of the flexible DuPont™ thermoplastic elastomer Hytrel® and the tough Crastin® PBT. as a result, this would increase the comfort known from most solid plastic chairs; it is characteriszd by observations of sitting behaviour, context and production technique. so, ‘to achieve an outstanding design, extraordinary comfort and movement, the aim was to design the most challenging typology of a chair—a cantilever chair,’ explains the designer. 

close up view of the DCC

the main theme of the chair is flexible sitting, which is addressed in different scenarios —flexible in movement, context and sitting postures. so far, there are only two cantilever chairs made from plastic on the market, but do not display the flexibility one would expect of a cantilever chair. in this case, the context concerned is that of is public space – both indoors and outdoors of cafés, restaurants, canteens, museums, libraries, universities etc. in the process, the double cantilever chair (DCC) has been consciously designed with the research of the particular context, material, design history and sitting behaviour in mind. in frederic rätsch’s opinion, it is essential that design does not become something arbitrary or stylized. hence the chair is characterized by e.g. the need of putting it on a table for cleaning the floor, the need for agile sitting, and for adaptation to outdoor qualities. 

stacking  DCC on tables is important in restaurants, canteens etc. to clean the floor

in short, DCC achieves the comfort of upholstered furniture through the use of high performance plastics. it features an elastic seat made of hytrel®, that allows adaption to the body. visually, it is totally flat and solid, and therefore provides a surprising moment when actually being soft and flexible. on the other hand, the crastin® PBT with its strength and stiff properties is the perfect material to support the seat shell, while still allowing some flexibility.

the flexible and elastic seat is visually totally flat, but surprisingly adapts to the body

the design process was driven by a constant exchange between the computer and full-scale model making. CAD models have been used as a tool to record the process and allow FEA, stackability tests and arrangements in the chair’s context. while wire and cardboard models helped to define the design idea, further models in polystyrene foam or plywood enabled the basic seating comfort to be assessed. with further development, the institute of plastic processing in aachen, germany, supported the project with the production of a 3D printed full-scale prototype, which is using Hytrel® for the seat shell to showcase the intended flexibility.

Rips in the back reinforce the seat and show a certain understanding of the material

‘observation of people’s sitting behaviour and a holistic understanding of the project have been key from the start. Unlike in other projects, it was not possible to use the actual material of the chair in the process. this asked for a very different approach from the beginning,’ elaborates frederic rätsch. 

DCC consists of two parts: a soft and flexible seat which sits on a strong structure

the very first model of the fundamental design idea

the exchange between full-scale model making and the simulations on the computer was key in the process

the particular design of the chair’s base achieves an extraordinary leg space

the design is characterized by the contrast of a rather soft and calm front view and a more dynamic side view

front view

the handle underlines the chair’s ability of being stacked on tables and its mobility in the space

designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: lea zeitoun | designboom