The concretion project consists of sand-casting aluminium in a base of stainless steel tubes to form objects. The tubes are placed and cut to certain heights according to what the gross object’s dimensions will be. The shapes of each horizontal surface are then prepared by hand without following any precise plan. Each pouring of aluminium is at the same time forming surfaces of the object as well as connecting elements together. The aim of this process is to create a strong relation between two types of metal: the industrial stainless steel and the brut hand-cast aluminium, that comes visually as an extension of the first one. The two types of metal have two opposite relation to time, the industrial tube can’t be placed in time, only resulting from a continuous chain of production when the hand-cast part captures the very moment of formation of the object. This opposition is not meant to compare which materiality is best, but to enrich each other by their difference.