'21 CHAIR

MECHANICAL STRUCTURE

The '21 CHAIR's design was achieved after several iterations looking for the ideal compromise between minimal material use and comfort. In fact, the chair's structural design was conceived from the beginning as a metaphor for this search for a balance: by putting together tension and compression elements the right way, a perfect, almost fun to see equilibrium of forces can be reached.

As much as the concept behind it stayed the same —playfully combining ropes and extruded tubes—, the mechanical structure's balance between simplicity and comfort shifted both ways throughout its several iterations:

Another key design aspect that was pursued from the beginning was structural honesty: in accordance with its minimalistic aims, the structure's joints are always left visible, unapologetically laying the beauty of these industrial elements bare, and also making it easier for the user to detach and reassemble the chair's components when needed.

MATERIAL SELECTION

Following the project's intention to build a sustainable, accessible, easy-to-move chair, all chosen materials had to be recyclable, light and cheap. The material selection was carried out following these basic principles, while also looking for the most appropriate solution to satisfy each component's mechanical and comfort requirements.

Aluminum  

The high purity aluminum extrusion tube defines the main structure of the '21 CHAIR.

Aluminum is a very light metal with respect to its remarkable mechanical properties. In addition, it is not only 100% recyclable, but recycling it can provide energy savings of up to 95% compared to obtaining it from ore.

To accomplish its glossy finish, this tube is subjected to a polishing process that can achieve similar results to those of chrome-plated steel, a material whose cost and weight are higher.

Polypropilene  

Both the seat and back of the chair are made of polypropylene (PP) by injection molding. 

PP is a widely used, low cost polymer that can be recycled. This material is very light compared to other polymers with similar properties, such as HDPE. Furthermore, it allows for brighter, more aesthetic finishes.

Faux leather  

The injection-molded seat is also protected by a synthetic leather cover that gives it a softer, more pleasant touch.

Synthetic leather is obtained from polyurethane by a water-based process that avoids toxic solvents (DMF-free).

Cotton 

The sturdy cords of the '21 CHAIR perform the structural function of supporting the back end of the seat.

These cords are made of cotton, which is the most widely used natural fiber given its excellent durability, fineness and, above all, softness. Additionally, the CHAIR '21 cords' cotton is micro-woven on the outside, giving them an even smoother touch.

Steel  

The chair's bolted joints are made of stainless steel.

Steel is the most commonly used material for this type of joints, due to its excellent resistance and durability. In addition, it is relatively inexpensive, and alloying it with chrome and nickel makes it stainless and gives it a good shine when polished. Just like aluminum, it is 100% recyclable, and thanks to its magnetic properties, it can be very easily recovered in recycling plants.