Soldering paste has come into extensive use in electrical work as a flux for soldering, says the u Brass World. " This has been brought about by the requirements of the electrical trade that in certain forms of soldering no acid shall be used. For soldering copper wires for electrical conductors, soldering paste is almost exclusively used. It has also entered other fields of soldering, particularly in instances where spattering and corrosion are objectionable.

Soldering paste which is now used in the electrical trades consists of a mixture of a grease and chloride of zinc. The grease which is commonly used is a petroleum residue such as vasaline or petrolatum. Such a material is about right in consistency. The proportions which are used are as follows:

Petrolatum

l lb.

Saturate Solution Chloride of Zinc

1 fluid oz.

The use of petrolatum instead of vasaline is recommended. While they are identical in composition, the name " vasaline " is registered as a trade-mark and commands a higher price on this account. Petrolatum is much cheaper.

The chloride of zinc solution is made by dissolving as much zinc in strong muriatic acid as it will take up. An excess of zinc should be present and all the acid neutralized. This will form a thick, oily solution. The petrolatum and chloride of zinc are mixed and thoroughly incorporated by means of a mortar and pestle, or by vigorous stirring. The advantage of this soldering paste lies in the fact that it does not spatter and is not corrosive.