A look at the different factors that influence the rate at which glass slumps into a mold. Things such as temperature, length of time within the slumping zone, and the width of the span of the mold all influence how deep a slump will be. The thickness and viscosity of the glass are also important. The slumping technique known as “low and slow” is recommended for success in slumping. This article was originally published on page 58 in the Fall 2020 issue of Glass Patterns Quarterly. by Bob Leatherbarrow