How to solder aluminum

Aluminum is one of the most convenient materials in construction practice. A little inferior in the strength of steel, it is much easier to process, has good electrical and thermal conductivity, and a beautiful appearance

However, the main problem that arises among amateurs when working with aluminum is its soldering. Just because aluminum does not solder. The reason for the impossibility of brazing aluminum by conventional methods is the ability in air to form oxide films very quickly (in fractions of a second). Therefore, previously developed technologies require either special mercury fluxes or special replaceable tips for soldering irons.

Most often, the need for soldering aluminum occurs when repairing resonant voltage stabilizers. In order to save, all windings of industrial network stabilizers are made of aluminum wire. Soldering these wires themselves is not necessary. It is enough to screw a well-soldered wire to them in any way convenient for you and to solder not this aluminum, but this wire.

But what if it is necessary to solder not conductors, but, for example, the most uncomfortable flat surfaces for soldering?

The proposed method is carried out using conventional solder and rosin with a conventional soldering iron. Since aluminum conducts heat very well, it is better to take a powerful soldering iron 60-100 watts. If the power of your soldering iron is not enough to heat large soldered parts, use additional parallel heating using a gas or electric stove.

Before joining, the place of soldering should be thoroughly rubbed with any crumbling stone (sandstone, brick, a piece of dried mortar containing sand, etc.). The stone cleans the surface of aluminum from a thick oxide film. Sand and dust generated during the cleaning process must be left in place of soldering. Immediately after rubbing, the surface of aluminum is covered with a layer of molten rosin.

Further, the soldering technique differs little from the soldering of ordinary materials, except that now the soldering iron sting needs to be wiped more thoroughly in order to destroy with a sand a thin film of oxides that have formed on the cleaned surface before applying rosin.

The strength of brazed aluminum is higher than the strength of brazed copper. This is explained by the low melting point of aluminum (much lower than that of copper), as well as the great ability of aluminum to diffuse into other metals.

Among all the methods I have known for brazing aluminum, this method is the simplest, cheapest and most convenient. It is also suitable for soldering any other metals.