How to solder thick aluminum

How to solder aluminum at home with a soldering iron

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Aluminum is highly durable and a good conductor of heat and electricity. It has a low specific gravity, is easy to process, and is environmentally friendly. However, all these positive qualities create almost insurmountable obstacles when solving the problem of how to solder aluminum at home with a soldering iron. This cannot be done using traditional methods, so you have to use special welding methods and optimally selected materials.

Technical difficulties in soldering aluminum products and parts

Soldering aluminum structures and other elements is always quite difficult, especially if it is done at home by novice craftsmen who have not fully studied the process. Basically, such soldering is performed industrially using special equipment. However, it is quite possible to create the most suitable conditions for welding parts made of aluminum.

To achieve this goal, it is necessary to resolve several technical problems:

• The biggest problem when soldering is caused by oxidation in the form of a film that appears on the surface as a result of contact between aluminum and air. Even if the metal is prepared, a coating forms on it almost immediately afterward. Such a film coating interferes with the joining process and adds many problems during the tinning and soldering process. In this situation, conventional types of solders and fluxes are completely unsuitable, since they do not guarantee a high-quality connection. The film is removed either by physical-mechanical means or with the help of strong chemicals.
• One should also take into account the high temperatures at which aluminum begins to melt. It reaches a maximum of 6000C. A temperature difference arises between the metal being soldered and its film, causing difficulties in the soldering process.
• Due to the temperature regime, aluminum begins to noticeably lose its strength during the heating process. This moment occurs when the material being welded is heated to 250-300 degrees. Some aluminum alloys contain components whose melting point differs from the base metal.
• Weak interaction of aluminum with traditional types of solders, consisting mainly of tin, cadmium and other elements. This leads to insufficient strength characteristics and reliability of the created seams. The problem of how to solder is solved using special solders containing zinc, which, in turn, has excellent contact with aluminum and penetrates into it. Adhesion occurs at the molecular level, providing the necessary strength of the connection.

Preparation for soldering aluminum parts

Great importance is attached to preparing aluminum for upcoming soldering.

There are several ways to do this to ensure connection reliability:

• The connection area is pre-degreased and treated with rosin. After the substance is applied to the surface, sandpaper is placed here. Next, you need to turn on a powerful soldering iron and press the sandpaper firmly against the surface.
• After this, the surface is rubbed and polished, and the joint itself is simultaneously tinning. An aluminum part is installed on the prepared surface, which can be soldered according to the usual scheme. If necessary, rosin can be replaced with oil used in sewing machines.
• In the second option, metal shavings are added to the rosin, after which the resulting mixture is applied to the surface of the future joint. The soldering iron tip needs to be well heated and tinned, and then rub it over the entire working surface of the parts to be soldered until the chips melt. At the same time, solder is added here. In this case, the oxide is removed mechanically, and the solder immediately falls on the surface and protects it from the reappearance of the oxide film.
• The third method is to pre-clean the surface. For this purpose, copper is used, through which the oxide film is removed. This method is one of the most difficult, since copper plating of the surface must be carried out in a special bath.

Selection of solder and flux for aluminum

Tin- and lead-based solders can be used to weld wires, elements and parts made of aluminum, provided they are thoroughly cleaned. Such soldering must be carried out using special flux solutions consisting of highly active substances.

However, such connections have insufficient strength due to the weak interaction of aluminum products with tin and lead, and the tendency to form corrosion. Therefore, special compounds are used in the form of anti-corrosion coating for surfaces made of this metal.

These compounds include solders containing copper, zinc, aluminum and silicon. They are produced both in our country and abroad. Among domestic brands, the most widely used is TsOP-40, which contains 40% zinc and 60% tin, as well as compound 34A with aluminum (66%), copper (28%) and silicon (6%). zinc affects not only the strength of aluminum contacts, but also their resistance to corrosion.

Of all the known solders, the minimum temperature at which they begin to melt is those based on tin and lead. The highest melting point belongs to compounds with an aluminum-silicon structure, as well as with aluminum, copper and silicon.

In the first case, similar types of solders melt when the temperature reaches 590-600 degrees, and in the second - at 530-550 degrees.

They are selected for each specific case, when parts with large dimensions, with good heat dissipation or refractory aluminum connections are connected.

Technological processes are inextricably linked with special types of fluxes used for better interaction of all welding components.

Selecting the most suitable material is considered a rather difficult undertaking. This is especially important when the process uses tin-lead solder. The structure of such fluxes includes elements that form its increased activity when interacting with aluminum. Among them are triethanolamine, ammonium fluoroborate, zinc fluoroborate and other similar components.

One of the most popular flux substances produced in Russia is the F64 substance, which is characterized by high activity. The quality of this connection allows you to solder metal parts made of aluminum without removing the refractory oxide coating located on the surface.

Soldering aluminum components

The procedure and technical process for welding aluminum are exactly the same as for other types of non-ferrous metals.

Among home craftsmen, the following two options are most often used:

• High-temperature soldering used for welding large-sized elements. This category includes aluminum structures with thick walls and increased mass, which require a temperature of 550-6500C to heat up.
• Soldering at low temperatures of 250-3000C, which is quite enough for installing wires of electronic equipment and welding small items used in everyday life. Aluminum wires are connected in the same mode in any electrical network.

Connections at high temperatures occur using special heating elements. One of them is a burner, which requires gas in the form of propane or butane to operate. If such a burner is not available, home craftsmen use various types of blowtorches.

Welding at high temperatures requires constant control over the degree of heating of the surfaces of the parts being joined. To do this, take one of the refractory solders in a small amount, and after it begins to melt, we can talk about reaching the desired temperature.

In this case, the heating of the part stops, otherwise it will simply melt and collapse.

Soldering at low temperatures is carried out with a 100-200 W electric soldering iron. The power of a soldering iron depends on the size of the components being connected: the larger the part, the more powerful a soldering iron will be required to heat it up. The conductors are easily connected with a 50 W soldering iron.

Regardless of the temperature conditions, connections are made in the same way, and all actions are performed in the following order:

• The place of future connection of parts or cables is processed mechanically. For this purpose, any cleaning agents are used that weaken oxidative deposits, providing more complete interaction with the flux substance.
• The joint must be degreased with acetone, gasoline, alcohol and other organic solvents.
• Before soldering aluminum with a soldering iron or torch at home, the parts are firmly fixed in the most convenient position.
• Flux is applied to the prepared surface. If the substance is used in liquid form, it is applied with a brush.
• The connection point is heated using an electric soldering iron of sufficient power or a gas burner. Next, molten solder is applied here and distributed in an even layer.
• Metal surfaces are connected and fixed in the desired position.
• After the solder has cooled and the parts have set, the joint is washed with running water. Flux residues are washed away and do not cause corrosion in the future.

Source: https://electric-220.ru/news/kak_pajat_aljuminij_v_domashnikh_uslovijakh_pajalnikom/2018-11-20-1605

How to solder aluminum with a gas torch - Technique Expert

Aluminum is a metal that is difficult to solder. This is due to its tendency to form a strong oxide film on the surface of products, which prevents the part from being wetted by molten solder.

Mechanical cleaning of the surface alone does not help, since new oxide is formed instantly after removing the old one. For this reason, special fluxes are used for soldering aluminum and special technology is followed.

Connecting wires

Typically, aluminum soldering is used in cases where the parts to be joined are small enough and the use of argon welding is impossible or absent. One example of the use of soldering is connecting electrical wires made of different materials.

Often in practice it is necessary to connect copper and aluminum wires. Such connections cannot be made by twisting, since this pair of metals forms a source of electrochemical corrosion . In this case, soldering aluminum to copper can be an excellent connection option.

This operation can be performed with ordinary soft lead-tin solder, but you should use a special flux for soldering aluminum. The procedure must be performed in the following sequence:

• first you need to strip the copper wire and tin it using rosin;
• to tinning an aluminum wire, after mechanical stripping of the oxide film, it should be coated with a layer of flux for soldering aluminum;
• for better mechanical strength of the connection, tinned wires can be twisted;
• By heating the joint with a soldering iron and adding flux, the solder melts and a solder is formed.

The connection obtained in this way can be safely embedded in the wall; it will last for a very long time.

Removing the oxide film

Usually, if you have a good flux specifically designed for soldering aluminum, the use of any special tricks is not required; it is enough to mechanically clean it and moisten the surface to be soldered with flux.

It is also possible to use acid for soldering aluminum. They use hydrochloric acid in which zinc is dissolved (soldering acid), and fluxes based on orthophosphoric acid are also used.

But if such a flux is not available or, due to poor quality, does not provide soldering, you can go another way. There are several ways to remove the oxide film for successful tinning of the workpiece.

In rosin

An aluminum wire or other part can be freed from the oxide film by immersing it in liquid rosin. To do this, you can either melt it or prepare an alcohol solution.

After immersing the part in rosin, use a sharp knife to scrape off the oxide film. The rosin layer prevents the access of air and the formation of new oxide. After this, the part can be tinned using a heated soldering iron with solder.

Abrasive powder

In the absence of flux and rosin, aluminum soldering can be done as follows. A paste is prepared consisting of abrasive powder and transformer oil.

Fine metal filings can also be used as an abrasive. The workpiece is coated with this composition, after which it is rubbed with a hot soldering iron with solder.

As a result of this, the abrasive grains or metal shavings remove the film, and the surface is immediately wetted with solder without access to air. After tinning, the product can be easily soldered.

Chemical cleaning method

In essence, this method is nothing more than copper plating of an aluminum surface. It is performed as follows.

That part of the aluminum billet that is to be coated with a layer of copper is moistened with a solution of copper sulfate. Then take a direct current source with a voltage of 4.5 volts.

This could be a battery or accumulator. The aluminum part is connected to the negative terminal of the power source. A copper wire is connected to the positive terminal, the end of which is entangled in the bristles of a toothbrush.

Next, the brush is moistened with a solution of copper sulfate. The wire located in the bristles must be well moistened. After this, rub the area of ​​the part previously moistened with the solution with a brush.

As a result of the galvanic reaction, the surface of the aluminum is coated with a thin layer of copper, allowing it to be soldered as if it were a copper part.

Warming up the part

When soldering fairly massive parts, the power of a conventional electric soldering iron may not be enough to heat the workpiece to the required temperature.

You can use a gas burner to heat aluminum at home. For this purpose, it is better to use a portable burner powered by a small gas cartridge. In this case, you need to work very carefully. It is unacceptable to overheat the base metal to the point where it begins to melt.

You can also use a combined heating method. For example, place a massive aluminum piece on the burner of a kitchen gas stove and light a small fire. You can use an electric soldering iron at the soldering site.

Everything that has been said about methods for soldering aluminum applies to various alloys based on this metal. Only the topic of silumin soldering is somewhat isolated. This material is an aluminum alloy containing silicon (roughly speaking, sand).

Soldering this alloy presents particular difficulties. Attempts to solder silumin often fail.

Even after seemingly successful soldering, it turns out that the connection does not have the required strength and may break. Experts do not recommend soldering this material. The best way to join this alloy is argon arc welding.

High temperature process

Industrial methods of aluminum soldering are distinguished by the use of harder solders containing aluminum. To use this technology, factory equipment and special fluxes are required.

Thus, heating and soldering of workpieces is carried out in special tunnel-type furnaces. The soldering process is carried out in an environment of inert gases at temperatures reaching 600 ℃. This technology is used in the manufacture of aluminum radiators and heat exchangers of modern cars.

Source: https://kumselstroy.ru/drugie/kak-payat-alyuminij-gazovoj-gorelkoj.html

How to solder aluminum at home: solder for soldering, methods, features

The procedure for soldering aluminum elements at home is a very problematic process, which is facilitated by the use of special materials.

The work is complicated by the immediate appearance of a thin oxide film at the stripping site, which interferes with soldering. An additional difficulty is created by the material itself, which has a low melting point (+660 °C).

Using solder for soldering aluminum, special strong fluxes and following technology, you can independently solder almost any aluminum object.

Features and principles of soldering

The low temperature value of metal melting complicates the technological process of soldering, as well as repairing products with your own hands.

Parts very quickly lose strength when heated, and structures reduce stability when the temperature reaches 300 degrees.

Low-melting solders consisting of bismuth, cadmium, indium, and tin come into difficult contact with aluminum and do not provide sufficient strength. Excellent solubility is observed in the metal in combination with zinc, which makes the soldered areas highly reliable.

Before soldering begins, aluminum elements are well cleaned of oxides and dirt. To do this, you can use mechanical force with brushes or use special fluxes made from a potent composition. Before the procedure itself, be sure to tin the areas to be treated.

The tin coating will protect the part from the formation of oxides. In order to reliably solder aluminum products, it is necessary to choose the right heating tool, taking into account the volume of metal being processed.

In addition, the reliability of the connection depends on the alloy chosen, as well as the flux for soldering aluminum.

Soldering methods

Soldering of aluminum products is carried out with an electric soldering iron, a blowtorch or a gas torch. There are three ways to solder various aluminum objects:

• with rosin;
• using solders;
• electrochemical method.

With rosin

This option for soldering aluminum objects, wires, cables is used for small parts. To do this, the cleaned section of the electrical wire is covered with rosin and placed on a piece of sandpaper with a medium grain size. The wire is pressed from above with the tinned tip of a heated soldering iron. This action is carried out several times, after which the procedure of soldering the electrical wires itself is performed. You can use a rosin solution in diethyl ether.

In this case, the end of the soldering iron is not removed from the end being tinned, but rosin is added on top. An electric soldering iron with a power of about 50 W is suitable for twisting thin aluminum wires. With an aluminum thickness of about 1 mm, a 100 W soldering iron is required, and parts larger than 2 mm require preheating of the joint.

Using solders

This method is the most common and is used in electrical engineering, in the repair of automobile parts, as well as other products. Before soldering aluminum, the area to be soldered is pre-coated with an alloy and the tin-plated elements are subsequently connected. Pre-tinned parts are connected to each other, as well as to other alloys and metals.

Soldering of elements can be carried out using light alloy solders containing tin, zinc, and cadmium. In addition, refractory materials based on aluminum are actively used.

Why are light alloy compounds used? Because they allow you to solder an aluminum product at temperatures up to 400 degrees. This does not produce qualitative changes in the properties of the metal and maintains its strength.

Compositions with cadmium and tin do not create sufficient contact reliability and are susceptible to corrosive effects. Refractory materials containing zinc, copper, and aluminum-based silicon do not have these disadvantages.

Electrochemical method

This procedure requires a plating facility. With its help, copper plating is carried out on the surface of a product or wire. In its absence, independent processing of the part is used. To do this, apply a few drops of a saturated solution of copper sulfate to the area cleaned with sandpaper. After this, the negative pole of an independent power supply is connected to the workpiece.

They can be a battery, an accumulator, or any electrical rectifier. A cleaned copper wire with a diameter of about 1 mm, located in an insulated stand, is connected to the positive terminal. During the electrolysis process, copper will gradually deposit on the part, after which the area is tinning and dried using an electric soldering iron. After this, you can easily solder the tinned area.

Solders, materials, fluxes

Soldering of aluminum with tin is carried out subject to the use of highly active fluxes, as well as good cleaning of parts of the parts. Such tin compounds require additional coating with special compounds, since they have low strength and poor protection against corrosion processes.

How to solder aluminum elements? High-quality solder joints are obtained by using solders with silicon, aluminum, zinc, and copper. These materials are produced by both domestic and many foreign manufacturers.

Domestic brands of rods are represented by the most used solders TsOP40, which according to GOST contain 60% tin and 40% zinc, as well as 34A (aluminum - 66%, silicon - 6%, copper - 28%). The zinc used gives high strength to the contact area and provides good corrosion resistance.

Imported low-temperature alloys with excellent characteristics include HTS-2000, which provides maximum ease of use.

These alloys are used to work with large-sized parts (radiators, pipes) with high heat dissipation using a heating pad or objects made of aluminum alloys that have a fairly high melting temperature. Novice repairmen can familiarize themselves with the soldering process by watching an instructional video. This will help to avoid many unpleasant nuances during the work process.

In addition to solders, aluminum soldering requires the use of special fluxes containing ammonium fluoroborate, zinc fluoroborate, as well as triethanolamine and other elements. The most popular is the domestic F64, which has increased chemical activity. It can be used even without first removing the oxide film from products. In addition to it, 34A is used, containing lithium, potassium and zinc chlorides, as well as sodium fluoride.

Preparation of products

Reliability, as well as excellent quality of connections, is ensured not only by using the right technology, but also by preparatory work. These include the treatment of sealed surfaces. It is necessary to remove contaminants and thin oxide films.

Mechanical processing is carried out using sandpaper, a metal brush, stainless steel wire mesh or a grinding machine. In addition, various acid solutions are used for cleaning.

Surface degreasing is carried out using solvents, as well as gasoline or acetone. On the cleaned aluminum area, an oxide film appears almost immediately, but its thickness is significantly lower than the original one, which facilitates the soldering process.

Heating tools

How to solder aluminum at home? Electric soldering irons are used to solder small-sized aluminum products at home. They are a universal tool, quite convenient for soldering wires, repairing small tubes and other elements.

They require a minimum of working space, as well as the presence of an electrical network. Repair of large-sized products and welding are performed with a gas torch that uses argon, butane, and propane.

To solder aluminum objects at home, you can use a standard blowtorch.

When using gas burners, it is necessary to constantly monitor their flame, which characterizes a balanced supply of oxygen and gases. With the correct gas mixture, the fiery tongue has a bright blue color. A dim hue, as well as a small flame, indicate an excess of oxygen.

Technological process

The technology for soldering aluminum objects is similar to the process of joining parts of other metal materials. The first step is to clean and degrease the areas of future adhesion. Then the connected elements are installed in working position for ease of processing.

Flux is applied to the prepared area, and the initially cold product begins to heat up using an electric soldering iron or a torch. As the temperature rises, the solder bar begins to melt, which must constantly touch the surface of the elements, controlling the heating process.

Soldering aluminum elements at home with an electric soldering iron is done in a well-ventilated room, as hazardous compounds are released during operation.

Using flux-free solder requires compliance with some nuances. To prevent the oxide film from interfering with the alloy getting onto the parts, the end of the rod makes scratching movements along the area where the elements are soldered. This breaks the oxide integrity and the solder comes into contact with the metal being processed.

Destruction of the oxide layer during soldering can be done using another method. To do this, the area to be treated is scratched with a metal brush or a stainless steel rod.

To ensure maximum strength of aluminum parts in the soldered area, the treated areas are pre-tinned. Compliance with the technology of soldering aluminum elements guarantees excellent quality of the connection, as well as its protection against corrosion.

Source: https://oxmetall.ru/pajka/kak-payat-alyuminij

Soldering aluminum at home

instrument.guru > Metalworking > Soldering aluminum at home

Soldering aluminum at home is a real way to repair household utensils, household and automobile aluminum radiators, pipes, plumbing fixtures and much more. In industrial conditions, soldering and welding of parts made of this material is carried out using automated equipment. At home, soldering and welding aluminum is also possible.

• Preparing for work
• Determination of product alloy
• Solder selection
• Flux selection
• Tool selection
• Aluminum soldering process
• Product preparation
• Soldering the product
• One home method on how to solder aluminum with a soldering iron

To do this, use an ordinary soldering iron, ordinary POS-50 and POS-61 solders containing tin. In addition, it is possible to use a magnesium welding stick or use a gas torch.

Once you have chosen your solder, you need to select a soldering flux. The biggest secret when soldering aluminum is to work quickly , connecting the parts to be soldered immediately after they have been cleaned of oxide.

Determination of product alloy

It is necessary to determine the alloy of the parts being soldered, as far as possible, whether it is aluminum at all or not. Many aluminum items and parts in the household are aluminum alloys.

Many alloys can be successfully soldered at home using a home vice and a soldering iron. But some alloys can only be welded on an industrial welding machine. The composition of an aluminum part can be guessed based on the hardness of the material.

The softer the material appears when processed, the greater the amount of pure aluminum it contains. This is a condition for successful and high-quality rations.

Solder selection

1. If you are soldering aluminum with other metals, for example, aluminum and copper wires, then this soldering requires a special approach. Often in such cases, the aluminum wire itself, a small section of it, is covered with a layer of copper. Then they tin with regular solder and solder the wires.
2. Low temperature solder is required for soldering.

   Since the melting point of aluminum is 660 ºC, and it has good thermal conductivity, a necessary condition for successful soldering with a soldering iron is the need for a sufficiently low-melting solder containing tin, which means fast melting of the solder. In many cases, POS-50 solder is quite suitable. It is also possible to use POS-61 solder.

3. You can purchase special solders for soldering aluminum. These are alloys of aluminum with silicon and zinc.

   They are different, depending on what you will be joining - aluminum to aluminum or aluminum to copper and other materials. You must carefully read the label on the package.

Flux selection

It is necessary to select a suitable flux for soldering aluminum. Aluminum can be soldered in different ways.

Due to the fact that the main problem when soldering and welding aluminum is the removal of the oxide film from the surfaces of the parts being joined, different fluxes are used for different soldering methods. At home, use regular rosin or alkaline oil.

A saturated solution of copper sulfate is also used. In addition, regular sewing machine mineral oil, which can be purchased at a hardware store, is often used. It is applied directly to the aluminum.

Tool selection

• You need to choose the right heat source. For small parts, a soldering iron with a working power of up to 150 watts is quite suitable, but for massive parts, for example, a car radiator, a low-temperature gas burner is required. Its operating temperature is 315–425°C. It can provide good heating of the soldering areas of the product and rapid melting of the solder.
• Buy or collect additional equipment. When you join aluminum, you will need some kind of clamp or vise. In addition, after completing soldering, it is necessary to rinse the soldered surfaces in water or detergent to remove any remaining acid or oil fluxes. If a resin-based flux was used, then you need to wash the aluminum with acetone. Accordingly, this requires some kind of container or bath.
• Take care of your safety. Create a comfortable work area. Be sure to purchase a respirator mask to protect against toxic fumes. Work only in a well-ventilated area. When using liquid, and especially acidic fluxes, use a mask or safety glasses. When using a gas torch, aluminum can melt, so when working you need to use cotton overalls and boots.

Product preparation

1. Before joining pieces of aluminum, it is possible to pre-tin the pieces. This is useful when soldering complex structures. In this case, it is very easy to tighten the aluminum in a clamp and then solder it with a soldering iron or gas torch. Accordingly, this does not need to be done if you are sealing cracks or holes in one product.
2. Next, you need Clean the aluminum and its surface to be treated using a stainless steel brush. When exposed to air, aluminum quickly becomes coated with a layer of aluminum oxide, which cannot be tinned or soldered. Another condition for high-quality soldering is that you need to be prepared for quick cleaning, fluxing and soldering so that the aluminum does not have time to become covered with a new layer of oxide.

   A product that is heavily soiled or oxidized needs to be sanded and wiped with isopropyl alcohol or acetone.

3. Clamp soldered metal parts together. You need them to touch in the place where you want to solder them. For solder you need to leave a small gap, less than 1 mm. If the metal parts do not touch smoothly, then you need to make the ground areas smooth.

   There is another way to work. Since when working with aluminum you need to work quite quickly, you can lightly clamp the aluminum pieces together in a vice, clean them there, and then tighten the vice clamp firmly.

4. Next, quicklyBefore a new layer of aluminum oxide has formed, apply flux along the soldering area. To do this, you can use a wooden stick or a solder rod.

   This will ensure that the solder is drawn out over the entire joint area and a strong solder seam is achieved.

Soldering the product

Now you can heat the parts to be soldered. To do this, you can use a soldering iron with a power of up to 150 watts or a gas torch, depending on the mass of the product being soldered.

• Heat should be near the joint. You need to start heating from the lower end of the product. The direct flame of the torch can overheat the connection, and then all the work will go down the drain. Therefore, the torch tip must be kept at a distance of 10 - 15 mm from the metal surface. In order to evenly heat the seam being soldered, it is necessary to smoothly move the heat source in small circles across the soldered area. Please note that when using a soldering iron, it may take 10 minutes for it to reach the desired operating temperature. If, when heating the joint being soldered, the flux used turns black, this means that the heating temperature of the joint was too high. The flux must be removed and, after cooling, a new one must be added and work continued.
• After warming up the work area to the desired temperature, you need to apply solder. The heating temperature is determined by the color of the flux. In general, fluxes that are used for soldering aluminum become light brown in color and begin to bubble when they reach operating temperature. Bring the solder to the soldering area while continuing to heat the area indirectly from the opposite side of the part or a nearby surface. Continuing to move the soldering iron or torch along the soldered seam, it is necessary to achieve uniform spreading of the molten solder over the entire area of ​​the soldering area and the formation of a shiny, mirror-like surface.
• If a new layer of aluminum oxide has time to form on the surfaces to be soldered before applying the flux, the solder will not bond to the aluminum. Then the surfaces of the parts need to be cleaned again, flux added and soldered again. This situation may arise if the type of solder and flux are not suitable for working with aluminum and its alloys. Or the aluminum alloy of your product is really poorly soldered.
• After cooling the part to be soldered, it must be cleaned of any remaining flux and oxides formed at high soldering temperatures. If the flux used was water-based, it can be washed off with water or a neutral detergent. If the flux was made based on resin, then acetone can be used for cleaning. Sometimes an acid etching solution is used to remove oxides.

One home method on how to solder aluminum with a soldering iron

You need to prepare a small surface on an aluminum product by simply cleaning it. Apply a few drops of a concentrated solution of copper sulfate to this surface. Connect the aluminum product using a wire with a diameter of approximately 1 mm to a direct current source. Aluminum wire can be used. Fold the other copper wire to form a small disk. Connect the other end of this wire to the “+” DC source.

An ordinary incandescent lamp can be connected in series to this circuit at the appropriate voltage. A transformer rectifier from 3 to 12 volts, a rechargeable battery or even a flashlight battery with a voltage of 4.5 volts is suitable as a power source.

There are many videos online on . Here are instructions for successfully soldering aluminum.

After turning on the power source, the copper wire with a rolled up disk is brought to the soldering site a short distance and lowered into the previously applied solution of copper sulfate. There is no need to touch the aluminum product itself; the current must flow through the copper sulfate .

The light comes on and copper is electrolytically deposited onto the aluminum surface. After some time, the copper sulfate may boil and evaporate. Precipitated copper will remain in its place. Then this area can be tinned in the usual way and a copper wire can be soldered to it.

Source: https://instrument.guru/metalloobrabotka/pajka-alyuminiya-v-domashnih-usloviyah.html

Soldering aluminum

Industrial production of aluminum, by historical standards, began relatively recently. But during this time, this material has firmly entered our lives.

Its main parameters - high electrical and thermal conductivity, low weight, resistance to corrosion - have led to the fact that this metal has become the main material used in the aviation and space industries.

In addition, it is impossible to imagine the streets of our cities without aluminum; translucent structures (doors, windows, stained glass), advertising structures and much more are made from it.

Soldering aluminum

When processing it, it is permissible to use almost all types of processing - turning, stamping, casting, welding and soldering. The latest methods are used to produce permanent connections from aluminum blanks.

General principles of soldering aluminum at home

Many people sincerely believe that soldering aluminum at home is a rather complicated process. But in fact, everything is not so bad. If you use the appropriate solders and fluxes, then there should not be any particular difficulties. If a home craftsman solders aluminum parts using materials intended for copper or steel, the result will most likely be negative.

Soldering tools

Process Features

The difficulties of soldering aluminum are primarily due to the fact that there is an oxide film on its surface, which, unlike the base metal, has a higher melting point and is highly resistant to various chemicals.

It is this film that creates serious obstacles when using traditional solders and fluxes, and for example, if you solder aluminum with tin, it is difficult to guarantee a high-quality result.

To remove this film, either mechanical action or fluxes that contain strong chemicals are used.

The base metal itself, in this case aluminum, has a low melting point, about 660 °C. Such a difference between the melting temperature of the oxide film and the base metal also leads to complications in soldering.

This property of aluminum results in the heated aluminum becoming less durable. Thus, aluminum structures begin to lose stability already at a temperature of 250-300 °C. In addition, aluminum alloys may contain materials that begin to melt at temperatures of 500-650 °C.

Aluminum soldering diagram

A large number of solders include tin, cadmium and other components. Aluminum has difficulty coming into contact with these materials and this in turn leads to the fact that the seams produced using these solders are characterized by low reliability and strength. Meanwhile, zinc and aluminum have good solubility in each other. The use of zinc in solders makes it possible to impart high strength parameters to the seam.

Use of transformer oil

As noted above, the main obstacle when performing soldering is the presence of an oxide film. Before soldering aluminum it must be eliminated. To remove it, different methods are used, ranging from the use of an abrasive tool to special fluxes. In addition, there are “folk” methods. One of them is related to the use of transformer oil.

Transformer oil

To remove the oxide film, the following composition is used: transformer oil is added to the abrasive powder. With constant stirring, the result should be a paste-like mass. It must be applied to a previously cleaned soldering area. After this, the soldering iron tip must be thoroughly tinned and the prepared areas must be rubbed until tin appears. After this, the soldering areas must be washed and work can continue.

What kind of solder is used for soldering aluminum?

Most solders contain substances that do not dissolve in aluminum. That is why, to create permanent connections of aluminum parts, so-called refractory solders are used, made on the basis of aluminum, cadmium, zinc and some other substances.

Low-melting solders are also used for soldering aluminum.

Their use allows you to perform work at low temperatures. This allows connections to be created without changing the properties of the aluminum. But it should immediately be noted that the use of such materials cannot ensure the proper degree of corrosion resistance and strength of the joint.

Solder for soldering

Optimal soldering results can be obtained by using a composition that contains aluminum, copper, and zinc. Work with such solders must be performed with a soldering iron, the tip of which is heated to 350 °C. When connecting parts, you need to use flux, which consists of a mixture of oleic acid and lithium iodide.

The composition for joining aluminum parts can be prepared at home, or you can simply purchase it in a store.

One of the commercially available solders for aluminum is HTS-2000. Soldering can be done with this solder without using flux. The great thing about this compound is that it can penetrate the oxide film and can create strong molecular bonds. The service life of connections made using this alloy is 10 years.

How to solder correctly using a torch

The need for soldering aluminum and its alloys may arise both in industrial and domestic conditions. This process can be used when performing repairs on parts, but sometimes you have to deal with more extensive work.

Processing aluminum is associated with a number of difficulties and therefore traditional soldering technology materials do not always guarantee the proper result.

One of the frequently used methods for obtaining permanent connections is directly related to the use of a gas burner.

Working with aluminum means that the oxide film that is on the surface of the part prevents the parts from joining.

Soldering with a torch is significantly different from working with a soldering iron and is rightfully considered more practical. While working with the burner, the master can adjust the temperature. And this provides additional opportunities for surface treatment of workpieces. In this case, the thickness of the material does not play a special role. Sometimes when working with a burner, fluxes and additional surface treatment agents are used.

Soldering aluminum using a gas torch

Soldering aluminum with a gas torch in a home workshop allows you to preheat workpieces and consumables.

Undoubtedly, to obtain a high-quality connection, experience is required. The fact is that aluminum has a low melting point; therefore, consumables used in soldering have good fluidity. If the master makes a mistake, then there is a high probability that the solder will simply spread over the workpiece without ever getting into the seam.

What flux to use

Flux for soldering aluminum must be selected based on a set of factors. There is a so-called binary flux based on orthophosphoric acid. Fluxes of this class do not require additional rinsing. This material can also be used to solder other metals.

Types of fluxes for aluminum soldering

Advantages

Soldering is one of the ways to obtain permanent metal joints. But unlike other methods, until recently it was characterized by low productivity and low strength at the junction. This and a number of other reasons led to the fact that it did not receive widespread industrial use.

With the development of technology, methods for connecting parts using an electron beam and ultrasonic waves have become available. The emergence of special solders and fluxes has significantly improved the quality of solder joints.

Modern soldering technologies make it possible to use finished products without further processing on mechanical equipment. Soldering has become one of the main technological processes in mechanical engineering, aviation and space industries and, of course, electronics.

Soldering has a number of undoubted advantages compared to welding. The process of joining parts in this way takes place with significantly less heat consumption.

In other words, during this process there are no major changes in the structure of the metal. Its physical and chemical parameters remain virtually unchanged.

After soldering, phenomena such as residual deformation may occur; its dimensions are incomparable with those that remain after, for example, welding in a cloud of shielding gases.

That is why the use of soldering guarantees more accurate compliance with the dimensions specified in the technical documentation for the product. Using this method allows you to join dissimilar metals. In addition, we can say that these processes can be automated quite easily.

Flaws

When talking about soldering aluminum parts, we must always remember that to work with it it is necessary to use special solders and fluxes that are able to meet the requirements for the quality of the resulting joints.

The slightest violation of technology or the use of unsuitable materials will lead to the fact that the resulting seam will not meet quality requirements.

Source: https://stankiexpert.ru/spravochnik/svarka/pajka-aluminiya.html

Methods for soldering aluminum wires

Despite the fact that in modern construction, during electrical work, aluminum cables are increasingly being replaced by copper cables, aluminum remains an indispensable material in the manufacture of large-section wires and cables.

The reasons for this lie on the surface - the electrical resistivity of aluminum is approximately one and a half times greater than that of copper, and the volumetric weight is three times less.

With a large conductor cross-section, when weight is more important than strength, the choice in favor of aluminum is obvious. The cross-sectional area of ​​an aluminum conductor will be one and a half times greater than that of a copper conductor, and at the same time, aluminum will still be two times lighter than copper. Soldering, among other methods, is used to connect wires.

Soldering methods

The problem with using aluminum conductors is their rapid oxidation. The oxide film significantly impedes the passage of electric current during connections. To do this, twisted aluminum wires are soldered.

You can solder aluminum wires in a junction box using a soldering iron or a gas torch. It is more difficult to use a soldering iron due to the inability to accurately heat to the required temperature. And for aluminum, overheating is just as unacceptable as underheating.

Metal has high thermal conductivity, and the insulation over a large area from the soldering point can simply melt.

It is easier to regulate the heating temperature with a gas burner, but it takes a long time to prepare the surface. However, it is the torch that will need to be used if it is necessary to solder any massive parts to each other. In any case, when soldering aluminum wires, they need to be prepared.

Preliminary processing

The difficulty with soldering is that aluminum itself is a very low-melting material (660 ℃) and if heated carelessly it can melt.

Another factor that makes soldering aluminum wires difficult is rapid oxidation in air.

The oxide film on the surface of the material reliably protects aluminum from the effects of all kinds of external factors, but it also prevents the adhesion of solder to the material and must be removed.

It is almost impossible to mechanically remove the oxide film under normal conditions. The material is instantly oxidized and covered with a new film. You can mechanically remove the oxide film under the oil layer.

But before this, the oil must be heated to 200 ℃ in order to remove any active oxygen that may be present there. This method is very inconvenient at home and labor-intensive.

Therefore, the ends of aluminum conductors must be tinned before soldering. Using rosin or most other fluxes will not work due to the high chemical resistance of the oxide film. It does not dissolve even with organic acids.

To tin the wires, you must use both a special flux and a mechanical method.

Of course, this must be done before the wires are twisted, otherwise it will not be possible to mechanically clean the entire surface of the wire. Only the tinned ends can be twisted together and soldered.

Working with a soldering iron

In order to solder aluminum with a soldering iron, there are several methods, the essence of which is to clean immediately under the flux layer in direct contact with the molten solder.

The first method is that aluminum conductors, before soldering, are cleaned with a hot tinned soldering iron using a mixture of rosin and steel filings.

Sawdust has an abrasive effect, rosin removes all impurities and immediately the cleaned areas are covered with solder, which should be on the soldering iron tip.

The second method involves stripping the aluminum wire on medium-grit sandpaper directly under the influence of a hot soldering iron with solder and flux.

Gas burner

Processing with a gas burner is carried out when the parts are in the position relative to each other in which they will be used. The processing smoothly transitions into the soldering process itself.

This happens as follows:

• the burner heats the surfaces of aluminum parts;
• upon reaching the temperature at which the metal is reduced from the oxide, the film is mechanically peeled off;
• under the influence of a flame, the parts are coated with flux, and solder is introduced into the soldering area.

If the parts are thick, then their edges must be cut at an angle of 45°. Typically, heating occurs to the melting point of tin, when the solder spreads and fills the twist groove.

Differences in technology when using flux

Thanks to the achievements of modern science and technology, flux compositions for aluminum have been obtained that actively dissolve the oxide film and protect the material from further oxidation.

Examples of such drugs are formulations labeled F-59A and F-61A. The letter A means that these compounds are intended for soldering aluminum.

When using these fluxes, soldering aluminum wires is greatly facilitated. It is enough to simply treat the finished twist with flux, without even heating it, and then, after heating it with a soldering iron or torch, apply solder.

It will spread over the entire surface of the wires and adhere well, providing a strong and electrically conductive solder joint.

Features of soldering stranded wires

Stranded wires must be soldered only using a special flux, since their mechanical processing is almost impossible. Soldering technology differs in that each wire must first be well treated with flux.

To do this, the bundle will have to be untwisted and fluffed. After processing, each thin wire conductor is covered with solder and the bundle is twisted. After this, twist the two ends and solder it.

Can it be connected to copper?

Situations often arise when it is necessary to connect an aluminum wire to a copper wire. This is perhaps the only case where soldering cannot be used.

It's all about the aluminum itself. It cannot be soldered to other metals at all due to its physical and chemical properties. When connecting directly to copper, galvanic corrosion will occur between the two active metals and will quickly destroy the connection.

And if they are soldered using solder that is neutral to both materials, then the different coefficients of thermal expansion of the metals will quickly destroy the soldered contact. After all, when current passes through a conductor, it will certainly heat up, and after switching off, it will cool down.

Safety precautions

Safety precautions when soldering aluminum wires boil down to observing general precautions when working with electric heating devices, open flames and aggressive liquids, such as fluxes.

It is unacceptable to use faulty soldering irons with damaged insulation and with more power than necessary.

Do not use burners near flammable objects. When working indoors, forced ventilation must be properly organized.

Difficulties in soldering aluminum wires

The main difficulty when soldering aluminum wires, as indicated above, is the presence of an oxide film on the surface of the metal. Fighting it greatly slows down the soldering process.

And if you consider that aluminum wires are now used mainly for laying external power wiring, it becomes obvious that a regular soldering iron and sandpaper will not be enough in this case. Welding is increasingly being used to connect such wires.

Source: https://svaring.com/soldering/praktika/pajka-aljuminievyh-provodov

How to solder aluminum to aluminum

There is a widespread belief that it is impossible to solder or tin aluminum (as well as alloys based on it) without special equipment for this.

Two factors are cited as an argument:

1. upon contact with air, a chemically resistant and refractory oxide film (AL2O3) is formed on the surface of the aluminum part, resulting in an obstacle to the tinning process;
2. The soldering process is significantly complicated by the fact that aluminum melts at a temperature of 660°C (for alloys this ranges from 500 to 640°C). In addition, the metal loses strength when, during the heating process, its temperature rises to 300°C (for alloys up to 250°C), which can cause a violation of the stability of aluminum structures.

Considering the above factors, it is truly impossible to solder aluminum using conventional means. The use of strong fluxes in combination with the use of special solders will help solve the problem. Let us consider these materials in detail.

Solder

Commonly used low-melting solder bases are tin (Sn), lead (Pb), cadmium (Cd), bismuth (Bi) and zinc (Zn). The problem is that aluminum is practically insoluble in these metals (with the exception of zinc), which makes the connection unreliable.

By using a flux with high activity and properly treating the joints, you can use tin-lead solder, but it is better to avoid such a solution. Moreover, a solder joint based on the Sn-Pb system has low corrosion resistance. Applying a paint coating to the soldering area allows you to get rid of this drawback.

For soldering aluminum parts, it is advisable to use solder based on silicon, copper, aluminum, silver or zinc. For example 34A, which consists of aluminum (66%), copper (28%) and silicon (6%), or the more common TsOP-40 (Sn - 60%, Zn - 40%).

Domestic solder – TsOP-40

Note that the higher the percentage of zinc in the solder, the stronger the connection and the higher its resistance to corrosion.

High-temperature solder is considered to be solder consisting of metals such as copper, silicon and aluminum. For example, like the above-mentioned domestic solder 34A, or its foreign analogue “Aluminium-13”, which contains 87% aluminum and 13% silicon, which allows soldering at temperatures from 590 to 600°C.

"Aluminum-13" produced by Chemet

When choosing a flux, it is necessary to take into account that not all of them can be active towards aluminum. We can recommend using products from a domestic manufacturer for such purposes - F-59A, F-61A, F-64, they consist of ammonium fluoroborates with the addition of triethanolamine. As a rule, the bottle is marked “for aluminum” or “for aluminum soldering.”

Domestic flux

For high-temperature soldering, you should purchase flux produced under the brand 34A. It consists of potassium chloride (50%), lithium chloride (32%), sodium fluoride (10%) and zinc chloride (8%). This composition is most optimal if high-temperature soldering is performed.

Recommended flux for packing at high temperatures

Surface preparation

Before you begin tinning, you must complete the following steps:

• degrease the surface using acetone, gasoline or any other solvent;
• remove the oxide film from the place where soldering will be performed. For cleaning, use sandpaper, an abrasive wheel or a brush with steel wire bristles. As an alternative, etching can be used, but this procedure is not so common due to its specificity.

It should be taken into account that it will not be possible to completely remove the oxide film, since a new formation will immediately appear in the cleaned area. Therefore, stripping is carried out not with the goal of completely removing the film, but to reduce its thickness in order to simplify the task of the flux.

Heating the soldering area

To solder small parts, you can use a soldering iron with a power of at least 100W. Massive items will require a more powerful heating tool.

Soldering iron 300 Watt

The best option for heating is to use a gas burner or blowtorch.

Simple gas burner

When using a burner as a heating tool, the following nuances should be taken into account:

• Do not overheat the base metal, as it may melt. Therefore, it is necessary to regularly monitor the temperature during the process. This can be done by touching the solder to the heated element. Melting the solder will let you know that the required temperature has been reached;
• Oxygen should not be used to enrich the gas mixture, since it promotes strong oxidation of the metal surface.

Soldering instructions

The process of soldering aluminum parts does not have its own distinctive features; it is carried out in the same way as with steel or copper.

The algorithm of actions is as follows:

• the soldering area is degreased and cleaned;
• the parts are fixed in the desired position;
• the connection area heats up;
• touch the solder rod (containing active flux) to the joint. If flux-free solder is used, then flux is applied to destroy the oxide film, after which a solid piece of solder is rubbed over the soldering area.

A brush with steel wire bristles is also used to break down the aluminum oxide film. This simple tool is used to rub molten solder over an aluminum surface.

Soldering aluminum - complete video instructions

Source: https://moy-instrument.ru/masteru/kak-spayat-alyuminij-s-alyuminiem.html

Soldering aluminum to steel

Often in amateur radio practice, and just in everyday life, the question of soldering aluminum arises. Electrical wires, housings, leaky containers - you never know. But unfortunately, aluminum and its alloys really don’t like to be soldered.

Even tinning this material (coating it with a layer of solder) is a problem, let alone soldering it properly. The only way out, as is commonly believed, is welding, and special welding, for example, argon-arc.

However, aluminum can still be soldered, and efficiently, at home and without the use of special tools and technologies.

Why aluminum can't be soldered

“It doesn’t solder” is not a completely correct statement. Rather, it doesn't solder well. The thing is that aluminum almost instantly oxidizes in air, becoming covered with an exceptionally strong oxide film, which is not covered by any other metal. But if this film is destroyed, then soldering aluminum is no more difficult than copper. Another thing is that aluminum oxide is a very strong compound. You've probably heard about cutters made of corundum, and this is aluminum oxide.

On the one hand, this oxide layer reliably protects aluminum from further oxidation and destruction, but on the other hand, it significantly complicates the soldering process. Moreover, it is impossible to destroy it with ordinary neutral fluxes - the same rosin. But if you still find such a flux, you can solder aluminum at home without any problems.

Fluxes for aluminum soldering

As mentioned above, the aluminum oxide film is extremely durable, and it is very difficult to destroy it using chemical methods.

Nevertheless, there are many compositions that allow this very film not only to destroy, but also to prevent the appearance of a new oxide layer before the soldering process is completed.

When choosing a particular flux, you should first of all focus on the type of soldering - soldering iron or torch. An incorrectly chosen composition will either not give the desired result if it is underheated, or it will simply burn in the flame of, for example, a gas burner.

If you are going to work with low-melting solders and use a soldering iron, then it makes sense to pay attention to F-59A flux and others like it (F61A, F64, etc.). It is highly active and perfectly destroys even a thick layer of oxide film at a relatively low heating temperature with a conventional soldering iron.

But it cannot be used for soldering with a torch and high-temperature solders. If the same F-59A even manages to destroy the oxide, during further heating it will simply burn, but its task is not only to remove corundum, but also to prevent the oxidation of aluminum until the end of the soldering process.

To work with high-temperature solders, you will have to use something else, for example, F-34A flux (AF-4A, Castolin 190 Flux, etc.), capable of withstanding temperatures up to 610 degrees.

High temperature flux for aluminum

Why is it not suitable for working with a soldering iron? Since the lower threshold of activity of this flux is 520 degrees, you simply cannot heat it with a soldering iron to the desired temperature, and therefore activate it.

Of course, the choice of the master is not limited to the above compositions. There are a great variety of them - both domestic and imported. So you have a lot to choose from, based on both cost and availability.

Solders for aluminum

Aluminum can be soldered with both ordinary lead-tin solders and special ones containing aluminum, zinc, silver and other metals and even non-metals (for example, silicon). POS solders, like those special for aluminum, have different melting temperatures, which must be taken into account both when working with them and when operating the repaired product.

If you decide to solder dishes that come into contact with food (canister, flask, distiller tube, etc.), then solders containing lead cannot be used. You will have to do high temperature soldering , using, for example, 34A solder, containing copper, silicon and, of course, aluminum. TsOP-40 containing zinc is suitable.

Solders 34A (left) and TsOP-40

Among the foreign ones, we can recommend Aluminum-13, which, in fact, is an analogue of 34A.

Solder for soldering aluminum Aluminum-13

Another option is soldering with pure tin. It is great for repairing food utensils and has a low melting point, which means the work can be done with a soldering iron. But when using tin, make sure that the soldering area does not get too hot during the operation of the product. For example, you can seal the bottom of a kettle with tin (it comes into contact with water and will not heat up above 100 degrees), but the beak of the same kettle will fall off after the first boil.

Tin can be used to solder food utensils

The so-called fluxed ones, which already contain a special flux (usually in the form of a coating, but not necessarily), deserve special attention. There is an opinion that flux is not needed at all to work with them and, in principle, this is true.

Nevertheless, it is very desirable for protecting the soldering area from oxidation during operation. Any passive flux that can withstand soldering temperatures is suitable for these purposes.

The ideal solution here would be ordinary transformer oil, which electricians use when soldering high-voltage couplings.

Aluminum solder with flux coating

Among the disadvantages of flux solders, one can note their higher cost, disposability (you do not reuse unused solder, but it has already been heated once) and the need for experience in working with such compositions.

Selecting a Heat Source

There is not much choice here:

• regular soldering iron;
• open fire.

The first option is suitable if you do not need special mechanical strength of the connection. For example, you need to solder two wires for reliable electrical contact or some part that does not carry a large mechanical load. Let's say a mug with holes so it doesn't leak. The second option involves one or another type of burner and the use of refractory solder. It is much more complicated than the first, but allows you to get a strong mechanical connection, as they say, for centuries.

Soldering metal with a regular soldering iron

As mentioned above, you can solder aluminum using low-melting solders using a regular and familiar soldering iron. The only condition is that the power of the tool must be sufficient to heat the parts being soldered to the required temperature.

Any soldering iron is suitable for soldering aluminum.

If you know how to work with a soldering iron, then you will not have any problems with soldering aluminum (or almost not). Clean the parts, coat them with appropriate flux and solder them. It’s a good idea to add a little fine abrasive to the soldering area, lubricated with flux, which will help clean the soldered surfaces from the oxide film.

If you do not have a soldering iron of sufficient power at your disposal, then the parts to be soldered can be heated in parallel with a burner (not too much) or even with the flame of a gas burner.

Some electricians generally manage to solder aluminum “with what they have”, and in the sense of electrical strength, solder with high quality. You can also use this method when connecting, for example, two aluminum wires. To do this you will need:

• any abrasive powder, such as fine sand;
• regular machine oil (gun oil is better).

You pour the abrasive onto a flat surface, drip oil, immerse the stripped aluminum wire in the composition and, taking solder on the tip, “rub” this same wire with it. The abrasive strips off the oxide, the oil prevents the formation of a new film, and the solder reliably covers the aluminum.

The only drawback of this method is the low mechanical strength of the connection, so before finally soldering the conductors, they must be twisted after tinning. The electrical strength of such a pack is excellent, so if it is not broken mechanically, it will last for decades.

Application of a gas burner

If you decide to use refractory solders for soldering aluminum, then you cannot do without an open flame. In this case, you will have to pay attention to the following nuances:

• The flame must be of high quality - not smoke, maintain a constant temperature and torch size.
• Open flame soldering requires considerable experience in maintaining the optimal heating temperature, since the “temperature corridor” for high-quality soldering is quite narrow. Overheated - the aluminum lost mechanical strength or even leaked. If not heated enough, the refractory solder does not melt.

To fulfill the first condition, for example, a fire or a candle flame is not suitable - they smoke. Gas stove burner? It does not smoke, but it is very difficult even for a professional to maintain the heating temperature of the parts being soldered - the slightest movement vertically or horizontally and the temperature “goes away”.

In addition, you cannot take the gas burner in your hand, and therefore you will have to hold the soldered parts in your hands.

If it's a massive object, you simply won't be able to hold it in the flame in constant motion to maintain the desired temperature while simultaneously trying to solder with your other hand.

Well, since you will be heating from below, for normal soldering you will have to overheat the part (you need to solder from above), which means it can easily melt. Nevertheless, at the very least it is possible to solder aluminum over gas, but only at the very least.

The ideal option would be a gas burner. It is compact (in the sense of the burner itself, and not the cylinder attached to it), does not smoke, and weighs little. But unfortunately, it is not always possible to get it.

The easiest way out of the situation may be a small blowtorch. To make it easier, simply do not fill the device with gasoline “under the neck”. Before you start soldering, the lamp must be warmed up properly so that it does not smoke.

Aluminum can be soldered with a gas or gasoline torch.

We will assume that the burner is heated up, and the parts to be soldered are cleaned and pressed tightly against each other at the place of future soldering. Apply the appropriate flux to the parts (if you are using flux-free solder, then use transformer oil as the flux) and start heating. The heating temperature must be constantly monitored with a piece of solder, touching the place of future soldering.

Once the solder begins to melt, try to keep the temperature constant (this will come with practice) and rub a piece of solder onto the solder area, completely tinning it. Once the tinning is finished, you can solder with the same piece, using it as an electrode for welding. Often, when soldering couplings, electricians use refractory solder only to tin the cable sheath, and then solder the coupling with ordinary low-melting solder.

The fact is that the coupling is made of lead and simply cannot withstand the heat required to melt refractory aluminum solder. But if both parts are aluminum, of course, it is better to solder and tin with refractory solder - the junction of the parts will have high both electrical and mechanical strength.

How to solder silumin

First of all, let’s define that silumin is an alloy of aluminum with silicon and nothing else. For example, TsAM alloy (zinc, aluminum, magnesium) is a completely different material.

If you are sure that you are holding a silumin part in your hands, then you can safely take up soldering - silumin can be soldered using the same technology as aluminum. Another thing is that silumin parts usually operate under a fairly high mechanical load.

The material is already, to put it mildly, bad in this regard, but if you solder it

Do you still want to solder a broken silumin faucet? In principle, this is real, but it’s still worth pitying the neighbors below. As for the TsAM alloy, which in appearance is very similar to silumin, it will not be possible to solder it efficiently and firmly. Just “slobber.”

Source: https://rem-serv.com/payka-alyuminiya-so-stalyu/

How to solder aluminum: rules and methods for do-it-yourself aluminum soldering

A reliable way to connect wires when laying electrical communications is soldering. Unlike aluminum, copper conductors are easy to tinning. This imposes restrictions on the applicability of materials for electrical installations. But sometimes working with aluminum cannot be avoided. Soldering wires must follow certain rules. But after learning simple tinning methods, you can make the connection yourself.

Soldering aluminum wires

During electrical installation, the metal cores of the cables are connected by soldering. This guarantees reliable contact at the commutation point. However, while it is easy to apply solder to copper wire, coating aluminum conductor is a little more difficult. In addition, it is impossible to directly connect two metals - they form a galvanic couple. When an electric current passes through the twist, it will heat up.

For your information!

When cleaning the core, it is important not to damage the base metal. Notched aluminum can break easily.

The difficulty of soldering lies in the fact that there is an oxide film on the surface of the metal that is difficult to remove. It is formed instantly when aluminum comes into contact with oxygen in the air. This is due to the high chemical activity of the metal. Without the protective film, it would completely react with oxygen. To ensure that the solder evenly covers the wire and holds tightly to it, its surface is cleaned by etching with fluxes or without access to air.

Required materials and tools

For tinning, first of all you will need a soldering iron. For work, take a device with a power of about 60 W. Soldering is carried out in a well-ventilated area: when the flux is heated, toxic fumes are formed. It is advisable to equip the workplace with a hood. In addition, you should prepare the following:

1. Flux, soldering acid or rosin. The latter is diluted with alcohol in a ratio of 3:2.
2. Sharp knife.
3. Pliers, side cutters.
4. Fine grit sandpaper.
5. Electrical tape or heat shrink tubing.

Submerged Soldering

To remove the oxide film from the surface of aluminum, various fluxes are used (F-59A, FTBF-A, F-61A). The use of a certain composition depends on the characteristics of the metal and its further purpose. Soldering sequence:

1. Clean the core from insulation at a distance of 5 cm from the edge. In this case, the knife is held at an angle so as not to damage the core.
2. The metal surface is cleaned with fine sandpaper.
3. Cover the core with flux using a brush.
4. Clean the metal again with a knife.
5. The wire is tinned with a heated soldering iron.

Important!

Solder is applied from the end of the wire to avoid damage to the insulation.

During tinning, the soldering iron is moved back and forth along the wire, clearing the film from the aluminum surface. It will not be possible to coat the core evenly with solder the first time. The procedure is repeated for open areas. After obtaining the desired result, the end of the wire is washed with an aqueous solution of soda (5 tablespoons per 200 ml of liquid) to neutralize active acids. Flux residue under the insulation or solder will corrode the aluminum over time. As a result, the joint will heat up and char.

Tin and rosin

According to the operating rules for electrical installations, soldering of aluminum wires with acids is prohibited. This is due to the fact that the active substances cannot be completely removed. They react with the metal, destroying it. A seemingly reliable connection may break during operation.

Note!

To avoid possible breakage, aluminum is tinned using rosin dissolved in alcohol. However, this method cannot be used in hard-to-reach places.

The liquid mixture is prepared in a shallow metal bath. The viscosity should provide good coverage of the conductor. The depth of the container depends on the diameter of the core.

Tinning sequence:

1. The wire, stripped of insulation, is placed at the bottom of the bath. Pour in liquid rosin. The latter should exceed the metal by 5-8 mm.
2. Using a sharp knife directly in the liquid, scrape off the protective film from all sides of the core. Without air access in the rosin solution, the metal does not oxidize.
3. With a heated soldering iron they begin to tin the wire. The point of contact of the tip with the metal should be in the liquid at a distance of 2-3 mm from its surface. The core is covered around the circumference with gradual pulling out of the wire. When in contact with liquid, the tip will cool greatly. It is necessary to make stops to warm up the soldering iron.

Important!

Tinning in a solution of rosin with alcohol is associated with a lot of smoke - the procedure is performed outdoors or in a well-ventilated area.

When installing electrical wiring, soldering aluminum conductors will not cause any difficulties. To ensure reliable contact, it is enough to tin the metal surface using various fluxes or rosin.

Source: https://VGrafike.ru/pajka-aljuminievyh-provodov-slozhnosti-i-hitrosti/