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
Glass-coated wire or oil. However. there are some apparatuses that can bypass some of these problems by heating the glass and the metal in separate chambers which allows for the use of metals with high melting points. Around the 1950s the Taylor-Ulitovski process was changed to a continuous feeding process of the materials in order to make these wires on a mass production scale. Metal cores in the range 1 to 120 micrometres with a glass coating a few micrometres in diameter can be readily produced by this method. Glass-coated microwires successfully produced by this method include copper, silver, gold, iron, platinum,