Measurement of solder-flux-vapor surface tension by a modified maximum bubble pressure technique

Abstract

While it is widely known that flux is needed to maintain an oxide-free surface during soldering, the fact that flux also reduces the surface tension between solder and ambient is neither widely recognized nor treated extensively in the literature. An apparatus is described which quantitatively evaluates the reduction of surface tension in the presence of flux. Representative data of eutectic lead-tin with water white rosin fluxes are presented.