Abstract: A method of forming an air-tight scal between two pieces of glass is described. It comprises the steps of: (a) introducing a layer of indium or indium alloy between opposing surfaces of the glass pieces; and (b) heating the indium or indium alloy layers and the glass pieces, preferably under vacuum, to a temperature, generally around or below 220° C., to melt the layers to form the seal between the pieces. The method is suitable to form a relatively small air-type seal between two glass panes or sheets, and is particularly suitable for the formation of evacuated double glazing units. Optionally, an additional metal layer is located between the indium or indium alloy layers.