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
Ancient Egyptian pottery of decorative techniques and motifs, many of which are characteristic of specific periods. There are three points in the manufacturing process in which decoration could be added: before, during, or after the firing process. Since the predynastic period, potters added decorative elements in the molding stage, creating unusual shapes or imitating other materials, like basketwork, metal, wood or stone. The majority of the 'fancy features' were created during the process of shaping the vessel and smoothing its surfaces, long before it was fired. The elements were either shaped from a piece of clay by hand or impressed into the clay