Sand casting is the technique of pouring molten glass -- between 1250° and 1350° C -- into impressions made in sand which serve as molds. The best sand is the same used in the casting of metal . The moistened sand is placed and held in a wooden box, then stamped with a form made of wood, clay or plaster, thereby creating the negative form in bas-relief of the future piece. To prevent the sand from sticking to the surface of the piece, a separator such as graphite must be used. Pouring glass as well as metal is a dangerous and vigorous activity which requires a well synchronized team to ensure an even flow and a homogenous product. The first cooling stage must be carefully controlled to make sure the edges as well as the center cool evenly. At approximately 600°C the piece can be removed from its mold and placed in an annealer. The sand alone will color the glass, but color can also be added either on the surface or throughout the piece with compatible colored frit. It is also possible to insert into the piece bits of metal or glass prepared in advance.

This technique which provides many sculptural possibilities for glass, has become especially popular over the last thirty years among artists who have freed this medium from the ghetto of the decorative object.

Pioneer in the field of sand casting, the Swede Bertil Vallien has developed a body of work that is dreamlike and often dramatic, in which come face to face man and myth, time and death... Take for example his current predilection for enigmatic heads frozen in the ice of his characteristically intense and profound blue: Janus Series 2000.

BUBACCO Giovanna, CROUS Joan et Giacomo, “Technice e arte del Vetro”, Demetra, Cologna al Colli, 1999