Thermosetting polymers are those which start from liquid monomeric raw materials, and undergo cross-linking chemical reactions to form a solid polymer. The foam expansion reaction which is called the blowing reaction is usually relatively very fast. The foam expansion process is typically completed between 60 to 90 seconds in most thermosets foaming processes. The gelling reactions which build polymer structure, hardness and strength takes relatively long time to complete, typically requiring several hours for completion. The purpose of the fast blowing expansion reaction is to minimize drainage which leads to foam instabilities and poor foam quality or in the worse case complete foam collapse. Thus the need to expand quickly has to be balanced with the equal need to polymerize (i.e. gelling reaction) quickly enough to stabilize the foam, whilst not too fast to retard both the foam expansion and cell opening for flexible foams. In addition to the balanced gelling reaction, surface active agents are typically used to provide the complex interfacial phenomena that provide stabilization in foaming processes that begin from the liquid state. The Webinar will highlight the complexities encountered in production of thermosetting polymeric foams, including the role of surface active agents, the balance of blowing-to-gelling reaction to control both polymer and cellular properties.