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So, let's talk about how to solder aluminum. Those who are faced with this problem know that aluminum does not solder well. The reason is a thin oxide film that quickly forms on the surface of this metal in the open air. Therefore, special fluxes are used for brazing aluminum. I will demonstrate the process of brazing aluminum using the example of tinning and brazing of wire twists.
When installing wiring, I always give preference to solder joints. I believe that this method provides better electrical contact compared to the usual twisting of wires without soldering or crimping them in a sleeve or tip.
Soldering of twists from aluminum and copper wire

Necessary tools and materials


We will need:
  • a regular 40-watt soldering iron;
  • knife for stripping and stripping wires;
  • flux for brazing aluminum (F-61A, F-59A, F-64, etc.);
  • rosin solution in acetone or alcohol;
  • lead - tin solder;
  • cutting aluminum and copper wires with a cross section of 2.5 - 4 square meters. mm

Soldering of twists from aluminum and copper wire

Let's start soldering


Soldering of twisted aluminum wires


Let's start by soldering twisted aluminum wires. Before twisting the wires, you need to make sure that the surface of the aluminum conductors is clean. Otherwise, you need to strip the wire with a knife. The surface of the wire should be light silver, not dark gray.
Soldering of twists from aluminum and copper wire

We do the twisting with pliers.
Soldering of twists from aluminum and copper wire

We use a special flux for brazing aluminum. It can have a specific brand of F-61A, F-59A, F-64, etc., or simply called "flux for brazing aluminum." A 25 ml bottle costs about 45 rubles and lasts a long time.
Soldering of twists from aluminum and copper wire

Using a brush, apply the flux with a thin layer to the curl from all sides.
Soldering of twists from aluminum and copper wire

Heated to a working temperature soldering iron tip wetted with solder, slightly touching it. Stroking the twist with the working surface of the sting, apply solder to it.
Soldering of twists from aluminum and copper wire

Solder and aluminum are similar in color, but this does not interfere with how the solder spreads over the surface of the wires, filling the gaps between them. It is not worth overdoing with the amount of solder, a thin layer on the surface of aluminum is enough, frozen drops should be avoided.

Brazing


Soldering of twists from aluminum and copper wire

I solder the copper twists in the same way, only the flux in this case is a solution of rosin in acetone. I prepare it as follows. Pour about 30 ml of acetone into the bottle and gradually pour rosin into it, previously ground into powder. By mixing, I achieve complete dissolution of the rosin. As a result, the solution should acquire the color of a weak tea. I also apply the flux with a brush, the consumption of rosin is scanty, and due to the fluidity of acetone, the solution penetrates into the smallest gaps. If you use undissolved rosin, it turns out not so neatly, then you have to remove its excess.
Soldering of twists from aluminum and copper wire

Twisting of copper and aluminum wire


Soldering of twists from aluminum and copper wire

When installing electrical wiring, it is forbidden to carry out direct connection of wires with current-carrying conductors made of copper and aluminum. As a result of electrochemical processes, an oxide film forms at the interface between these metals, which increases the transition resistance. The presence of moisture activates the course of the reaction. As a result, the transition begins to heat up, which further accelerates the corrosion process. Copper with aluminum is connected through a third metal.Usually, a bolted connection is used with the installation between the wires of the steel washer, or special clamps that exclude direct contact of the wires.
Soldering of twists from aluminum and copper wire

Soldering of twists from aluminum and copper wire

If necessary, connect the wires to a copper and aluminum core, I proceed as follows.
Soldering of twists from aluminum and copper wire

The copper and aluminum wires that you want to connect, I pre-tin, that is, cover a thin layer of solder.
Soldering of twists from aluminum and copper wire

Soldering of twists from aluminum and copper wire

At the same time, I use my own flux for each metal, and I use the same solder. After that, I twist the wires and solder the twist from the outside. As a result, copper and aluminum wires are connected through a layer of solder separating them. Tin and lead included in the solder are chemically neutral to copper and aluminum, which eliminates the occurrence of electrochemical corrosion. The outer layer of solder, applied to the twist, seals the contact and protects it from external influences.
Soldering of twists from aluminum and copper wire

Sometimes you can hear the opinion that soldering twists carries a potential danger. It is believed that when the twist is overheated, the solder melts and, dripping, damages the insulation of other wires. Let's figure it out.
Soldering of twists from aluminum and copper wire

The twist itself, especially the soldered one, provides an electric contact area many times greater than the cross section of the main wire. And this means that when the wiring is overloaded, the heating of the twist will be the smallest. In this case, the wire will overheat along its entire length, which can lead to melting of the insulation much earlier than to the melting of the solder. The reason for this situation is not the presence of twisting, and not its soldering, but the absence of a circuit breaker or its incorrect selection.
As for the "destructive" action of the molten solder, in the process of soldering you can make sure that his drops accidentally dropped from the tip of the soldering iron do not burn even the newspaper on the table.

Conclusion


When soldering, observe basic safety precautions. Working with an electric soldering iron is fraught with the following hazards:
  • electric shock in case of malfunction (phase breakdown on the body and soldering iron tip);
  • the possibility of burns (the melting point of lead - tin solders is about 200 ° C).

Watch the video


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Comments (13)
  1. Akril
    #1 Akril Guests April 8, 2019 2:33 p.m.
    3
    In life, everything is much more prosaic and simpler than on the screen. I have not seen a single electrician soldering twisting wiring, pure water is nonsense and can only come in handy for a bet, I can solder or not. Judge for yourselves, the twisting is done within 5-10 seconds, and how long the soldering iron will be heated, how many preparations you need to make to solder it, and if there are hundreds of them, where do you get so much solder and flux?
    1. Evgeny Danilov
      #2 Evgeny Danilov Guests April 8, 2019 4:46 p.m.
      0
      And if you take into account how much aphthor breathes acetone ...
    2. Konstantin Sokolov
      #3 Konstantin Sokolov Guests April 8, 2019 8:28 p.m.
      0
      As far as I understand, there is a twist of aluminum with copper ... Such a twist without soldering will not last long, sparkle and burn out.
      1. Vita
        #4 Vita Guests April 9, 2019 09:39 a.m.
        2
        Konstantin carefully study the essence: soldering is what you need. But with acid in this case, I would not recommend it. Moreover, the result may be the same without it (chemistry). Well, you must be able to twist correctly.
    3. Vita
      #5 Vita Guests April 9, 2019 09:58
      3
      In vain, you are.Twisting can be good or bad, but the contact should always be good, especially at high currents. With soldering, it is more reliable, and even better, welding of the end of the twist.
  2. Guest Vitaliy
    #6 Guest Vitaliy Guests April 8, 2019 4:57 p.m.
    6
    An electrician, of course, will not bother with soldering, because he has a stream and there is no time to lick every wire.
    The tips given here are not for electricians, but for ordinary people who need to be done efficiently, reliably, for themselves. And while not, there are 1-2-10 twists that can be spent 10-20 minutes on.
  3. Guest Sergey
    #7 Guest Sergey Guests April 10, 2019 08:12
    2
    I have been working with electrics and electronics almost all my life. Soldered twist, as practice shows, is an extremely reliable connection. Crimps and bolt connections will not go into any comparison. But in the case of copper and aluminum, I would refrain from such a solution (only possible in case of emergency).
  4. Konstantin
    #8 Konstantin Guests April 10, 2019 2:38 p.m.
    0
    On an industrial scale, for example, during the construction of electrical wiring of multi-storey buildings, installation companies performing twisting of wires in junction boxes duplicate the same connections by welding conductors with special equipment, this gives a more reliable connection for almost the entire service life.
    1. Dmitry Spitsyn
      #9 Dmitry Spitsyn Visitors April 11, 2019 14:50
      0
      It is unlikely that they will weld copper with aluminum. The idea of ​​the author is good. Here are just a flux for aluminum most likely will not be at hand, and without it, aluminum can not be treated.
  5. Guest Yuri
    #10 Guest Yuri Guests April 11, 2019 08:45
    0
    IMHO. Copper twisting under PPE will cope with any tasks if the cable section is correctly selected. This is probably done up to 90% of the wiring connections in the apartments, and everything works.
    1. Vita
      #11 Vita Guests April 11, 2019 8:43 p.m.
      2
      Yuri, you know that at first they abandoned aluminum, but now, due to a shortage of copper, they decided to return to it again. Aluminum and copper are not compatible: electrocorrosion, especially in wet environments. Soldering is basically a mechanical and chemical twist protection.
      1. Akril
        #12 Akril Visitors April 12, 2019 11:19
        0
        Everything is not so critical that it is directly incompatible, under normal conditions of in-house lighting, for example, why not? I have laid the old aluminum wiring, brought the new copper, for 10 years no moore. Even with a load of 2 kW of appliances such as a kettle or vacuum cleaner, the only boiler on a separate power without any ration rations is worth it. And so, in life no one bothers with this.
        1. Alexey 163
          #13 Alexey 163 Guests July 7, 2019 10:36 p.m.
          0
          Well wait! HE usually comes unexpectedly! )
          And so, in life, NO ONE does!

          PS: electrician, experience 20 years, installation + maintenance ...

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