How aluminum is soldered

Since aluminum and its alloys oxidize rapidly when exposed to air, conventional soldering methods do not give satisfactory results.

The following method can be recommended for soldering aluminum with tin lead solders (POS).

Liquid mineral oil is applied to the aluminum at the brazing point, and the surface of the aluminum under the oil layer is cleaned with a scraper or knife blade to remove the oxide film. Solder is applied with a well-heated soldering iron. For soldering thin aluminum, a 50 W soldering iron is sufficient, for aluminum with a thickness of 1 km or more, it is desirable to use a 90 W soldering iron.

Better yet, apply gun oil; good and satisfactory soldering quality is achieved when using mineral oil for sewing machines and precision mechanisms, petroleum jelly.

Solder must contain at least 50% tin... The most convenient is low-melting solder POS-61. Solder POS-30 does not provide good soldering quality. When brazing aluminum thicker than 2 mm, it is recommended to heat the soldering point with a soldering iron before applying oil.