Abstract: Solder baths for use in the electronics industry are formed by converting into a molten condition a soft solder material in the form of an extruded bar of soft solder alloy having one or more cores composed of (I) esters of polyhydric alcohols of molecular weight of at least 300, (II) ester derivatives of rosin or modified rosin, (III) hydrocarbon resins, and/or (IV) polymeric waxes, so that the resulting solder bath is provided with a layer of anti-oxidant material derived from the cores which assists in preventing formation of oxide impurity on the surface of the molten solder bath and which may also act as a solder flux, thereby obviating the conventional necessity of applying a separate antioxidant material to the surface of the bath and of using a separate solder flux.

Abstract: Soft solder in the form of an extruded or cast bar or ingot is provided with a coating which prevents formation of surface oxide during storage of the bar or ingot and which acts as an anti-oxidant surface layer when the bar or ingot is used to form a molten solder bath. The coating may also act as a solder flux so that when a solder bath is formed from the soft solder bar or ingot, the anti-oxidant surface layer formed from the coating also acts as a flux composition hence obviating the necessity of employing a separate solder flux in a soldering operation in which the molten solder bath is used. The coating is formed from a coating material essentially comprising a mixture of a neutral ester of a polyhydric alcohol and an ester derivative of rosin or of a modified rosin.

Abstract: There is described a method of soft soldering aluminium or alloys thereof using a fluxed solder composition. The fluxed solder composition comprises a soldering flux suitable for use in soft soldering aluminium and its alloys and a soft solder alloy of lead, tin and silver and, optionally, up to 3% copper. The composition of the soft solder alloy is such that it contains at least 35% lead and 10% tin, and x% silver wherein x=0.1+(5.times.10.sup.-4)(Sn).sup.2 +(1.times.10.sup.-5)(Sn).sup.3, (Sn) being the percentage by weight of tin in the alloy.

Abstract: A flux composition of the non-corrosive type suitable for use in soft soldering, particularly in the electrical and electronics industries, contains in place of the conventional natural rosin (colophony), an ester of a polyhydric alcohol such as pentaerythritol tetrabenzoate. The composition can be in solid or liquid form and in the latter can perform the multiple functions of an etch resist, a protective coating and a flux in the production of printed circuit assemblies.