In lost-wax or investment casting, the artist starts with a full-sized model of the sculpture, most often a non-drying oil-based clay such as Plasticine model for smaller sculptures or for sculptures to be developed over an extended period (water-based clays must be protected from drying), and water-based clay for larger sculptures or for sculptures for which it is desired to capture a "gestural" quality - one that transmits the motion of the sculptor in addition to that of the subject. A mould is made from the clay pattern, either as a piece mould from plaster, or using flexible gel or similar rubber-like materials stabilized by a plaster jacket of several pieces. Often a plaster master will be made from this mould for further refinement. Such a plaster is a means of preserving the artwork until a patron may be found to finance a bronze casting, either from the original moulds or from a new mould made from the refined plaster positive.