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 marimba of mallets are used for different effects. The tuning system of a glass marimba can be whatever is desired. Glass marimbas are utilised by the Brazilian percussion ensemble, Uakti. Glass marimba can be constructed in a variety of ways. How one resonates the keys governs the construction method and design. Resonation can be accomplished using a single resonator which all the keys resonate into, such as an open top box, or individual resonators for each key which can be a tube, box, or sphere. Single box resonators can be constructed from wood, glass, or metal among a variety of materials.