An apparatus for depositing a selected pattern of solder onto a substrate comprising a substrate support, a solder ejector, and a gas-delivery system associated with the solder ejector. The substrate support has structure for bearing a substrate on which one or more electronic components are to be mounted. The solder ejector has a housing that defines an orifice for producing a stream of molten solder droplets along a selected trajectory relative to the substrate support to deposit molten solder onto the substrate in a selected pattern. The gas delivery system has an input for receiving pressurized inert gas and an output aligned with the directed stream of molten droplets for discharging from the orifice of the solder ejector a flow of inert gas aligned with the ejected molten solder droplets. A method for depositing a selected pattern of solder onto a substrate is also described.