Ron Arad, 2002 The design for Bad Tempered Chair dates back to the legendary Well Tempered Chair which marked the beginning of the collaboration between Ron Arad and Vitra. In formal terms, Bad Tempered Chair is largely identical to the original model but instead of being made of sheet metal, this chair is manufactured from a newly developed plastic that considerably improves the chair's practical usefulness. Materials: glass and carbon fibre laminate.