The Arbe Vacuum Pump is designed to provide eceptional performance for the demanding jewelry casting process. The pump features a two-stage, direct-drive system with 1/2 HP motor and 3 CFM free air displacement pump. Use this powerful, compact, vacuum pump to vacuum RTV molds or urethanes, investment and invested flasks, and to vacuum-cast small solid flasks. All RTV molds must be vacuumed to remove air bubbles. Instructions.