State-of-the-art brazing and soldering processes depend on favorable spreading conditions of molten metal over a reactive surface. Single or multiple grooves, ranging from mezzo and macro in size, can efficiently facilitate the flow of molten metal at macro distances prior to joint formation. This experimental study is devoted to a phenomenological investigation of molten metal flow through the grooves for: (1) Al alloy systems over Al substrate and (2) Sn-Pb systems over Cu substrate. Aluminum processing is conducted under controlled atmosphere brazing conditions. Real time monitoring of the molten metal flow along the grooves is performed using the hot stage microscopy and digital imaging techniques. Empirical data were corroborated with modeling of spreading following (1) modified Tanner’s law spreading correlations and (2) a theory based on a modified model of Washburn, advanced by Yost et al. This work is supported in part by the Kentucky Science and Engineering Foundation through the grant KSEF-829-RDE-007, National Science Foundation through the grant DMI-9908319, and the Kentucky KYRP Program.