How and with what to solder aluminum

Principles of aluminum soldering

Soldering aluminum is a complex process, since an oxide film forms on the surface, which interferes with the work. Therefore, it is necessary to use special techniques to simplify the workflow. Special fluxes will allow you to get rid of the negative factors of the oxide layer.

Process Features

The surface of aluminum parts is covered with an oxide film, which has high chemical resistance, as well as a melting point 2 times higher than pure metal. In the range from +2500С to +3000С aluminum becomes unstable and melts. The minimum melting temperature of the oxide film is +5000C.

When soldering, the parts being connected under the outer layer begin to melt. Therefore, the shareholder needs to eliminate the negative impact of the oxide layer. The principle of all methods is based on film removal, as well as increasing adhesive properties.

Methods for removing the oxide layer:

• mechanical - the use of abrasive tools for stripping;
• chemical - the use of fluxes with special compositions;
• electrochemical - based on electrolysis processes.

Both methods are carried out only in an environment without oxygen.

Materials used

To complete the work you will need to prepare the following materials:

To obtain high-quality seams, you need to use a flux for soldering aluminum based on zinc, silicon, and copper. The joints are strong, durable, resistant to corrosion, static and dynamic loads.

Solders with the following markings are suitable for soldering aluminum:

• TsOP-40 - refractory tin-zinc composition;
• POS - light alloy solder;
• 34A - alloy based on copper and silicon;
• “Aluminium-13” is a foreign analogue of 34A.

The use of flux improves the adhesion of metal to solder, resulting in a strong connection. The durability of the seam, the strength characteristics of the product, and the resistance of the material to the negative influences of the external environment depend on its choice. Fluxes contain active elements: zinc or ammonium fluoroborate, triethanolamine.

Solder fat comes in the following types:

• neutral based on rosin and stearin - it is thick, capable of removing small contaminants, and adheres well to the surface of the metals being welded;
• active with a complex chemical composition - effectively removes oxides and traces of corrosion, increases soldering properties.

The fat contains zinc and ammonium chloride, paraffin, and auxiliary substances.

Solder fat has the following advantages:

• easy tinning due to spreading in a thin layer;
• availability;
• dosage accuracy;
• no traces after use.

It is recommended to use the following brands of fluxes: F-64, F-61A, F-59A, 34A, F-5, F-124.

Scope of the process

Brazed aluminum products are used in the following areas:

• automotive industry;
• radio electronics;
• production of window frames;
• production of bicycle parts;
• creating frames for greenhouses and equipment buildings.

Soldering methods

There are the following soldering methods:

• with rosin;
• with solder;
• electrochemical.

With rosin

Step-by-step implementation of the method:

1. The soldering iron is warming up.
2. The tip is tinned to remove dirt or carbon deposits.
3. Rosin is applied to the joint seam and melted with a soldering iron.
4. After melting, use a sting to rub the surface until the oxide film is removed. At the same time, tinning occurs.
5. After the process is completed, the elements are joined, heated to the melting point, and then left to cool.

Using solders

The method using solder for soldering aluminum is implemented as follows:

1. The joining surfaces are cleaned mechanically.
2. The parts are securely fixed.
3. Local heating of the structure is performed.
4. The rod with solder is guided along the joint seam, simultaneously heating it with a burner until it melts.

If solder without flux is used, it will need to be used separately. It is pre-applied in an even layer on aluminum.

Electrochemical method

Step-by-step electrochemical soldering of aluminum:

1. The surface is cleaned of dirt, partly of the oxide film, mechanically.
2. Apply a thin layer of copper sulfate.
3. The negative electrode of the current source is connected to the part.
4. The positive electrode is connected to a high purity copper wire (diameter greater than 1 mm). It is located above the structure on a special stand, ensuring contact only with the treated area.
5. The power source turns on. The electrolysis process begins to take place.
6. After removing the oxide film, the wire is removed, and the parts are heated with a soldering iron to the melting temperature or solder is used.

To ensure high quality soldering, it is necessary to apply galvanic coatings with special tools. They will allow for uniform copper plating.

Preparing parts

In preparation for work, it is necessary to use the following surface treatment methods:

• degreasing is carried out using a solvent, using acetone, white spirit, gasoline;
• the oxide film is removed using abrasive tools or a soldering iron or gas torch is used to apply flux.

ALUMINUM SOLDERING. NO ARGON NEEDED!

General principles of soldering aluminum at home

Basic principles of soldering aluminum at home:

• it is necessary to perform high-quality cleaning of the metal surface from contaminants, coatings, and oxide films;
• the time interval between cleaning and soldering should be minimal;
• to remove the oxide film, it is better to use metal brushes or soldering irons with special attachments;
• the choice of heating tool is made depending on the soldering area, since aluminum cools quickly due to its high thermal conductivity;
• if there is no suitable solder, then it is allowed to use any solder that contains tin or lead;
• when heating parts for applying solder, it is important not to overheat aluminum, since it has a lower melting point compared to the oxide film;
• tinning the aluminum surface with a continuous layer will eliminate the appearance of oxides, which will simplify its soldering;
• when using a burner, it is important to follow fire safety rules, especially when applying degreasing solvents;
• soldering can be performed in several layers, before applying each you need to wait until the previous one hardens;
• the use of flux will require the use of protective equipment, since it may contain caustic substances;
• the burner flame should always be directed in the direction opposite to itself;
• For soldering, it is recommended to use soldering irons with a power of more than 100 W;
• flux is used mainly for elements with a thickness of 4 mm or more or surfaces with complex shapes;
• The composition of the solder is selected based on the type of soldering, but the melting point is always lower than that of aluminum;
• to solder workpieces with a thickness of more than 4 mm, along the edge of the butt seam you need to cut the edge at an angle of 450 to increase the contact surface;
• After carrying out the work, it is necessary to ensure the integrity, strength, and uniformity of the seam.

When choosing solder, you need to consider the type of tool used for melting.
Alloys with low melting points are suitable for a soldering iron: tin alloys with copper, zinc, bismuth. To create a refractory compound, you will need a complex alloy of aluminum, copper, and silicon. Verified! Soldering aluminum at home

Principles of aluminum soldering Link to main publication

Source: https://metalloy.ru/obrabotka/pajka/alyuminievyh-izdelij

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.

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

The process of joining aluminum and its alloys by soldering is a complex process, since the material does not have the best properties for this.

However, it is actively used in the industrial sector and parts made from it that need repair are found in various areas. Soldering aluminum at home is complicated by the fact that it is impossible to provide the same technical base as for industrial processing.

At the same time, aluminum itself is well processed mechanically, so preparing the metal will not be difficult.

Soldering aluminum

Almost the same methods are used here, and the appropriate solder for soldering aluminum is also selected. Sometimes improvised means are used as flux, such as aluminum metal shavings, rosin, etc.

They don't always help as much as the factory options, but they do provide improved connection quality. At home, wires, various housings of household appliances, aluminum cookware and other parts are most often soldered.

Despite the fact that soldering aluminum with a soldering iron at home does not require full compliance with technological requirements, they all improve the quality of the connection, so you need to comply with them as much as possible.

Aluminum soldering technology

Advantages

• Soldering aluminum at home is faster and easier, so the connection can be soldered in just a few minutes, having all the necessary things available;
• There is no need to use very powerful means, since the melting point of aluminum itself is lower than that of other metals, and accordingly, solders have an even lower melting point;
• Even if the entire procedure is performed at home, it turns out to be a very safe procedure;
• You can work with thin workpieces and wires without any problems, and you do not need to set high precision in the operating parameters of the equipment;
• The connections are strong even when working at home.

Flaws

• High risk of defects, all of which is complicated by the poor weldability of the metal;
• It is difficult to deal with the oxide film that forms on the metal surface almost instantly, even after mechanical cleaning, since its melting point is three times higher than the melting point of aluminum;
• When heating a metal, it is difficult to track the degree of its heating, since the color of the metal practically does not change at this time;
• If you overheat a metal, its structure will begin to change and it will lose its strength, therefore, you should not approach the melting point of the metal;
• At home, it is sometimes difficult to choose the right solder and flux.

Possible ways to solder aluminum at home

• Soldering using aluminum solders is the most standard method, which is very common at home. This happened due to its simplicity and accessibility, which does not exclude the high quality of the final result. This is where low-melting filler materials and fluxes come in handy to improve the quality of the connection. Both a povolnik and a gas burner can be used here.
• Soldering with a pencil at home is one of the simplest and most accessible methods, since it requires a minimum of tools. The pencil itself is a special light-alloy material that can melt when exposed to temperature and at the soldering site, after which it hardens on the surface. Despite the fact that the quality of the connection is lower than with the previous method, it is popular due to its simplicity.
• Soldering using a paste, which can be considered as solder of a peculiar consistency. It must first be distributed at the joint and then melted using appropriate tools. Soldering aluminum at home with a gas torch is much easier, since the paste easily melts from the flame and immediately spreads to all the necessary places.

Materials and tools

• A soldering iron is one of the main tools, since it is with its help that solder and flux are melted and the part is heated. Soldering irons vary in their power, as this is the main parameter that you should pay attention to when choosing. It determines in what temperature range the work will take place.
• A gas torch is an alternative main tool for soldering. It has higher functionality, since it can be used not only to heat the solder metal to a molten state, but also to heat the main workpiece. The burners also differ from each other in power, but it can be adjusted depending on the gas volume consumption per unit of time. The tool may also contain other additional functions.
• Flux is an additional consumable material that is used to improve soldering qualities. For aluminum itself and its alloys there can be different types of flux, which depends on the process technology.
• Solder refers to the basic consumable material that fills the soldering area. It should have high fluidity and wet the surface well. When choosing, you need to ensure that its melting point is lower than that of the base metal. The composition of the solder is selected depending on the welding method.

Step-by-step instruction

• Metal preparation, which includes mechanical cleaning with sandpaper or a fine wire brush, as well as surface treatment with a solvent such as acetone or any other.

Stripping aluminum

• Next, you should tin the soldering area using flux, which may also be required for the soldering iron tip in order to speed up the melting of the solder.

Flux for soldering aluminum

• After this, you can begin the soldering itself. To do this, you need to heat the soldering iron to the desired temperature, or adjust the burner, and then begin to melt the solder at the joint. This should be done in small parts so that the metal spreads evenly over the surface.

Solder for soldering aluminum

• Allow to cool and check the quality of the connection.

"Important!

Due to the high fluidity of solder, the workpieces should be placed on a flat surface so that they do not flow down at an angle.”

Soldering modes

Type of solder	Soldering mode	Maximum strength of alloys, kgf/mm2
AMts	AMg6	D20
P-300-A	440°C, 20 minutes	11	22	–
P-425-A	12	20,8	20,8
34A	550°C, 20 minutes	9-10	–	28,8
B-62	510°C, 15 minutes	12	–	23,8

Safety precautions

Soldering aluminum at home with a soldering iron, as when using a torch, must be carried out subject to all safety rules. First of all, this concerns the use of the main tool, since you should not leave it turned on, because a fire may occur from a heated soldering iron or a burning burner. There should always be a place where you can safely put a hot tool.

Some types of flux and solder emit an unpleasant odor when melted and can be toxic, therefore, when working with them, you should ensure sufficiently good ventilation conditions so as not to expose yourself to unnecessary danger.

Source: https://svarkaipayka.ru/tehnologia/svarka-alyuminiya/payka-alyuminiya-v-domashnih-usloviya.html

Soldering aluminum at home: techniques and principles, fluxes and solders

Aluminum is a material with good strength and high thermal and electrical conductivity. These positive qualities contribute to the widespread use of metal in industry and everyday life. Quite often there is a need to connect aluminum parts or seal a hole in an aluminum container. But not everyone knows how to solder aluminum at home.

Soldering aluminum

One of the most well-known methods of joining metals, especially in electrical work, is soldering. It provides lower resistance of connections, and, as a result, less heating under the influence of electric current. Since aluminum, along with copper , is the main conductive material in electrical networks and devices, the need for soldering arises quite often.

The difficulty is that the “winged metal” in air is instantly covered with a film of oxide, to which the molten solder does not stick. It is necessary to remove the oxide layer using mechanical cleaning, but it forms again almost instantly.

In order to avoid the re-formation of the oxide film, many techniques have been developed. Among them:

1. Cleaning small parts under a layer of liquid flux.
2. The use of fluxes in conjunction with abrasive materials.
3. Using copper sulfate to create a copper film on an aluminum product.
4. Application of special fluxes and solders.

Cleaning under the flux layer

Small aluminum parts, such as conductors, can be cleaned by dipping part of the part into a liquid flux, which can be a regular rosin solution or soldering acid. Liquid flux will protect the area being cleaned from contact with oxygen and the formation of a film. Regular transformer oil has the same protective effect.

Abrasive materials

Iron filings are often added to the flux (the same rosin). During the soldering process, it is necessary to rub the heated area with the tip of the soldering iron. Under the influence of friction, the sawdust peels off the oxide layer, and the rosin blocks the access of oxygen to the liberated metal. Instead of sawdust, any crumbling abrasive can be used: sandpaper or even brick.

Using copper sulfate

An interesting method using galvanostegy. Two aluminum electrodes are dipped into a solution of copper sulfate and connected to the poles of an electric battery. The electrode connected to the positive is stripped. As a result of electrolysis, copper begins to deposit on the cleaned surface. When the aluminum is completely covered with a copper film, the part is dried. After this, soldering is much easier, because copper is an excellent material for this type of connection.

Special solders

The highest quality connection at home can be obtained using low-melting solders based on tin and copper and special fluxes. The most popular domestic flux is F64, which allows you to solder aluminum parts without mechanical stripping. So, for example, soldering aluminum to copper can be done without problems, or an aluminum tube can be sealed from the inside, which cannot be cleaned by any other means.

In this case, conventional low-melting tin-lead solders with a melting point of 200−350 degrees are used. The soldering iron should be quite powerful - from 100 W and above. The reason is the high thermal conductivity of aluminum. An insufficiently powerful soldering iron simply will not be able to heat the soldering area to the melting temperature of the solder. Only very small parts (mainly in radio electronics) can be connected with a 60 W soldering iron.

A soldering iron is not suitable for soldering large aluminum parts. Here it is better to use any gas burner that provides heating up to 500-600 degrees, and one of the specialized solders. One of the most popular is HTS-2000 - a flux-free solder for soldering aluminum, copper, zinc and even titanium.

It has several advantages:

1. Low melting point (390 degrees Celsius).
2. Can be used without flux.
3. Reliability of the connection (in many cases it can replace argon welding).

True, HTS-2000 does not exclude the stripping process. Moreover, during the soldering process it is necessary to remove the oxide film with a solder rod or a wire brush to ensure a reliable connection. However, this method allows you to perform such work as sealing leaky aluminum containers, for example, cans, or even car aluminum radiators.

In addition, HTS-2000 is practically the only (with the exception of argon) way of joining two “winged” metals: aluminum and titanium.

There are other high temperature solders designed specifically for aluminum soldering. For example, 34A, which contains two-thirds aluminum, as well as copper and silicon. But the melting point of such solders is 500-600 degrees Celsius, which is close to the melting point of aluminum itself.

Therefore, using high-temperature solders at home is dangerous - an aluminum part can be irreparably damaged when heated to such high temperatures.

Source: https://tokar.guru/metally/alyuminiy/process-payki-alyuminiya-v-domashnih-usloviyah.html

How to solder aluminum with tin yourself

Soldering wire connections with solder is considered the most reliable method of connecting wires and cable cores. It’s good if you only need to solder copper wires, which are easily tinned with solder. It’s not for nothing that in electronics all terminals of elements are copper and tinned.

Soldering aluminum at home

Once solid wires and stranded cable strands are tinned, they are fairly easy to connect by soldering. How to solder aluminum with tin if the solder is rejected by aluminum oxide. As you know, aluminum is coated with a thin layer of oxide, which instantly forms on aluminum upon contact with oxygen. In order for the solder to adhere well to the aluminum wire, you need to remove the aluminum oxide and then tin it.

For this purpose, the following fluxes exist: soldering acid, special fluxes for aluminum, and a mixture of rosin and acetone. All these advantages destroy or hinder the formation of an oxide film on aluminum. After using this type of flux, the process of tinning aluminum is simplified.

The necessary tools for soldering aluminum with tin are: an electric soldering iron, a sharp knife, pliers for twisting wires, a small file for preparing the soldering iron tip. The materials you will need are: POS 61 or POS 50 solder, flux for soldering aluminum F-64 or similar, sponge.

Soldering aluminum with tin and flux F 64

Flux F 64 is intended for soldering aluminum. The soldering technique is not complicated. First of all, you need to remove 5 cm of insulation from the wires. The insulation is removed with a sharp knife at an angle to the wire so as not to cut it. Notched aluminum breaks off easily.

Tools and materials for soldering aluminum wire

Next, you need to thoroughly clean the wire with fine sandpaper or a sharp knife. Having stripped the wire, it is moistened with a brush with a plus and with a sharp knife they continue to strip the wire, but now under flux. In this way, the oxide film of the aluminum wire is removed, preventing it from oxidizing again in air. Next, using a heated soldering iron with solder, begin tinning the wire from its end.

If you start tinning the wire near the insulation, then you can burn it. In this case, the insulating properties of the wire will be lost. The wire is tinned with a soldering iron, moving back and forth, while the oxide film is removed from the aluminum. It is not possible to tin the wire straight away. Therefore, flux is again applied to the non-tinned sections of the wire and sections of the remaining oxide film are removed with a hot soldering iron with solder and movements back and forth and serviced.

In this way, the aluminum wire is completely covered with solder. After tinning, the aluminum wire is dipped in a soda solution (5 tablespoons per 200 grams of water) and the remaining flux is washed off with a toothbrush. The flux contains active acids that not only corrode the film, but also the wire itself. Therefore, the remaining flux must be washed off. It will not be possible to wash it off completely, since it partially remains under the solder and eats into the wire.

But at least partially it needs to be washed off. Copper wire is not treated with F 64 flux; it is better to use a solution of rosin and alcohol (50% to 50%). Using a brush, apply liquid rosin to the copper wire (having previously stripped it) and use a hot soldering iron to service the wire, starting from the end. The soldering iron tip should be smooth and clean. The shells at the end of the soldering iron tip are removed with a fine file.

And the remains of burnt solder (slag) are wiped off with a sponge or rag. Once the aluminum and copper wires are tinned, they are twisted with pliers, liquid rosin is applied with a brush and the connection is soldered, also starting from the end. If you connect aluminum without tinning with solder, the connection may break down over time. The aluminum-copper connection is a galvanic couple, and when current passes through it, it heats up and destroys the connection.

Table of temperature conditions of solder brands

As a result, the twisted area becomes very hot and charred, which increases the fire hazard. Tin solder is neutral to aluminum, so aluminum wires must be tinned before connecting to copper. POS 61 and POS 50 solders with a low melting point of 190 - 210C are well suited for soldering aluminum wires.

Soldering aluminum with copper, tin and rosin

Soldering electrical wires using soldering acid is prohibited in the PUE. This is due to the fact that this acid does not burn completely during soldering. As a result, the junction of the wires is corroded by acid over time, oxides are formed, which heat up when current passes and can cause the insulation to catch fire. These acid-containing fluxes include special fluxes for soldering aluminum, including F 64.

So how to solder aluminum with copper so that the connection is high-quality and durable. In terms of complexity, the method of tinning aluminum with tin and rosin is even easier than tinning aluminum with F 64 flux. But the quality and reliability when tinning with rosin will be high. When tinning aluminum in rosin, you need to make or select a low bath for liquid rosin (rosin 60% and alcohol 40%).

Fluxes for aluminum soldering

Fill the bath with liquid rosin so that the wire is buried in it with 5-10 mm of insulation. The wire, stripped of insulation, is placed in rosin and with a sharp knife (conveniently a scalpel) the oxide film is removed from the aluminum wire without removing it from the bath. That is, under rosin they protect the wire along its entire length from all sides. Under the rosin, a film does not form on the cleaned areas of the aluminum wire, since there is no contact with oxygen.

Now take a heated soldering iron with solder with a power of at least 60 W and lower it onto the bare and free of oxide wire, right at the surface of the rosin, little by little scroll and pull out the already tinned sections of the wire. The essence of the method is that the wire is tinned at the very surface of the liquid rosin. So that the stripped sections of the wire from oxide cannot come into contact with air.

The soldering iron can be immersed 2-3 mm in rosin at times. After tinning the wire a little, lift the soldering iron so that it heats up again. Yes, at the beginning, there will be a lot of smoke, so it is better to learn to solder outdoors or in a room with good ventilation. After several attempts, you will develop your own tinning technique and gain a little experience.

You will decide on the position of the soldering iron, the speed of tinning the wire will increase, that is, skill will appear, and the amount of smoke will decrease. But the wire will be perfectly tinned. Next, as usual, twist the wires and solder them with a small amount of solder.

The remaining rosin on the soldered twisted wires is washed off with a brush and alcohol. The disadvantage of this method is the impossibility of soldering in hard-to-reach places. For such cases, it is better to use other methods for safely connecting aluminum to copper.

Source: http://electricavdome.ru/kak-payat-alyuminij-olovom-svoimi-rukami.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.

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

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

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

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