Fourcault process the pit must be "heated back" and then the process can continue anew. Glass chemistry has a huge impact on the process since it controls the melting, forming and annealing temperatures, liquidus temperature (point where various chemicals that make up the glass start to crystallize out of the glass) and rates of change of characteristics of the glass itself. Occasionally the ribbon will break or crack, leading to failure of the drawing process. Such breaks, known as "checks" can be alleviated by using proper operating parameters. Sometimes an expedient measure, using a portable source of heat, can be used to
Heated glass surface of the glass between the busbars must be flat. An electric current flows across the tin(II) oxide coating from one busbar to the other. The electrical resistance of the coating produces heat energy, which radiates from the glass. The busbars are connected to a power control unit that regulates the flow of electricity and thus the temperature of the glass. In modern architectural projects the heated glass is completely translucent. This technology uses a special metallic coating on the surface of the glass invisible to the naked human eye. A pane of heated glass can achieve temperatures up to