Soldering of aluminum is carried out using tin-lead solder. But the process is complicated by the fact that aluminum is difficult to tin. Most often, aluminum flat surfaces or aluminum wires to aluminum or aluminum to copper are soldered.
The reason for poor soldering of aluminum is due to the fact that it itself is a very active metal and in air it is instantly covered with a very thin but durable layer of oxide film, which protects this metal from atmospheric influences.
Even if you clean the surface of the metal with ordinary sandpaper and try to tin it, nothing will work, because in a matter of seconds the metal is covered with the same oxide film.
Two common ways to solder aluminum at home
There are 2 solutions to this problem: either strip the metal under a protective medium, or use specialized fluxes. In the first case, we coat the surface with mineral oil and try to tin it.
To do this, we begin to scratch the surface of the metal under the surface of the oil, removing the oxide film. At the same time, the oil does not allow oxygen to penetrate to the metal, and it does not oxidize.
A small area can be cleaned with a powerful soldering iron, since aluminum is a very thermally conductive material, and as soon as we heat the surface, the temperature on it begins to drop.
Therefore, we take tin-lead solder and rub it in, but even under a layer of oil it is very difficult to do this, nevertheless, this method still works if you continue to rub for a long time. After the surface is “tinned”, remove the oil and solder the copper wire.
In the second option, we use a specialized flux for soldering aluminum, which contains all the elements that corrode the oxide film and react with the metal itself, which facilitates soldering.
In this case, it is low-temperature solder, which we drop onto the surface, and we see that hissing occurs, i.e., the flux itself interacts with the metal, and therefore tinning occurs, and it is possible to solder the wire.
Now we solder the wires together. Note that the first method under oil is not suitable for soldering wires due to the inconvenience of the place and the very difficult organization of the grout. And here flux for soldering wires - an irreplaceable thing. If there is a hissing sound, then the tinning has taken place and the overlap of the wires has occurred.
Next, let's try to connect the wires, when the end of one wire is twisted into a spring and another wire is inserted into it. To connect them, the contact needs to be tinned, so we cover it with flux and seal it.
Let's check the quality of soldering. With the first and second methods, the wires came off with difficulty. Therefore, both methods are absolutely workable. They can be used to tin an aluminum surface, except that the first method is only suitable for flat surfaces, and the second (with flux) for soldering wires.
