The Kester 197 mildly activated rosin liquid flux is a homogeneous solution of high quality purified grade WW rosin in a specially blended alcohol vehicle into which a very small amount of an extremely effective activating agent has been incorporated. The rosin residue is non-corrosive, non-conductive and moisture and fungus resistant. The dry rosin residue actually insulates the surface from atmospheric corrosion. - 197 has proven to be nearly as active in fluxing ability as highly activated rosin fluxes, but the flux and its residue are considerably less conductive. The low conductivity results from a minimum of ionic activating agent as shown by the very high water extract resistivity.