Gas that originates during casting in connection with air and the added binders, additives and facing coats.
These core gasses must be properly vented through core prints to avoid occurrence of gas blister defects and thus production of rejects (s. a. Core venting).
Gas development from organically bound molding materials (see Organic binder systems) is illustrated in a schematic diagram in Figure 1. Figs. 2 and 3 illustrate the development of gasses (gas quantity) and the gas surge (gas release rate) using the examples of various core mold materials.