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The development of a new type of flux—the surfactant flux—is described. This flux is applied in a very thin layer and must be totally dry before soldering. It is not necessary to clean PWBs after soldering for functional or aesthetic reasons. Even the results of the surface insulation resistance (SIR) test suggest no need for cleaning. The flux allows a very high soldering speed, at least double that of normal fluxes. Thus the heat input into the materials involved is minimised, with the consequence of less damage. It is not the chemicals which make the flux highly active but the concept. This new concept makes it possible to design non or low corrosive fluxes in a wide range for purposes where highly corrosive fluxes must be used today.

Protective cover coating of bare copper boards is necessary to resist long‐term storage. Both water‐soluble and rosin‐based fluxes are used in the evaluation. The inhibitors have been practically tested on coupons which were soldered after accelerated ageing tests. All investigations were carried out with respect to the impact on waste treatment, and the adjustment to various fluxes.