Pre-blends of Bentonites & lustrous carbon producers are preferred modes of dosing both these essential additives in a single measure in the green sand molding process in foundries. Pre-blends are specially preferred by those foundries where castings of near standard configuration and sand to metal rations are cast in highly automated molding lines and sand plants.

Pre-blends such as SANDIRON, while imparting ease of use as single dose additives, require careful monitoring where frequent changes of patterns are necessitated. Here a close working relationship between the pre-blend manufacture & the user foundry is recommended.