Abstract: A system for the preparation of no-bake foundry sands for preparation of metal casting molds. A settable binder is introduced into the sand and thoroughly and uniformly mixed therewith and then discharged around a pattern. The resulting mold then sets up and hardens rapidly without baking. After use to produce a metal casting, the mold is broken up and the sand recycled for further use. The present system is characterized by ease of feed rate variation, coordinated feeding of components, short residence time, efficient mixing and reduced clean-up problems. It comprises a horizontal axis paddle-type rotary mixer, coordinated means for feeding the mixture components to the mixer housing and discharge of the mixture upon demand including at least one gas assisted injection port or nozzle for the binder system and control means for regulating the rates of flow. The apparatus is desirably movably supported to facilitate distribution of the discharge.