The Kester 2120 is a halide-free, organic flux designed for automated soldering of circuit board assemblies. This flux provides good activity on both bare copper and solder coated boards. The absence of chlorides, bromides, phosphates and highly corrosive materials facilitates removal after soldering. 2120 produces bright, shiny solder joints and high ionic cleanliness after water cleaning. 2120 provides better surface insulation resistance than typical water soluble fluxes, making it particularly suitable for surface mount assemblies. - This flux does not attack properly cured solder resists or FR-4 epoxy-glass laminate. 2120 provides better chemical compatibility with solder resists than other water soluble fluxes. No offensive odors or excessive smoke is emitted during soldering. 2120 will not create excessive foaming in standard water cleaning systems. 2120 is completely biodegradable for environmentally safe disposal of the wash water.