How to solder aluminum without argon

DIY flux for soldering aluminum

People learned to solder metal products back in ancient times, as soon as they learned to smelt tin and lead. Of course, the simplest way to fasten metal products to each other is to use a regular bolt with a nut, because this does not require their preliminary preparation, the use of various solders, fluxes, etc. However, metal soldering is widely used both on an industrial scale and at home.

Before you start soldering, the surface of the parts to be joined is cleaned with sandpaper or a file and lubricated with flux. The heated soldering iron is immersed in ammonia or rosin to clean it of metal oxides, after which the molten solder is transferred to the soldering site.

As for aluminum or its alloys, rapid oxidation of the soldered surface occurs here, and conventional soldering methods do not give the expected result. The fact is that the surface of aluminum products is covered on top with a very thin, elastic, but at the same time quite durable film of aluminum oxide.

After removing it mechanically, the newly cleaned surface from contact with air is instantly covered with an oxide film. Despite this, soldering aluminum at home is possible. If soldering is performed using tin-lead solders, you can use the following method.

Liquid mineral oil is applied to the place of the upcoming soldering, and already under the oil layer the surface is cleaned with a knife blade or scraper to remove the oxide film. After this, you need to apply solder with a very heated soldering iron. Usually a 50 W soldering iron is sufficient for this. For aluminum products with a thickness of more than 1 mm, it is better to use a tool of greater power.

Instead of mineral oil, you can use sewing machine oil or Vaseline oil, but gun oil is best suited for this purpose. The solder used must contain at least 50% tin. A good result is achieved by using low-melting solder POS-61. If you are soldering aluminum with a thickness of 2 mm or more, the surface must be thoroughly heated with a soldering iron before applying oil to the soldering area.

You can also apply rosin mixed with fine iron filings to the seam. A tinned file is used to wipe the seam area with added solder. Sawdust plays the role of an abrasive material, removing the oxide film from the surface of the product with sharp edges. As a result, tin adheres firmly to the surface, and aluminum is soldered more reliably.

In order for the work to be especially effective, the soldering iron should be slightly modernized. To do this, the working part of the copper rod is blunted so that a platform 4-5 mm wide is formed on it, after which a small longitudinal cut (7-8 mm) must be made with a hacksaw.

From a hacksaw blade, previously calcined over a fire, you need to cut out a small piece (1-2 mm), treat it to remove scale with a 20% mixture of sulfuric or hydrochloric acid, place it in the cut and compress it tightly in a vice.

Such a tip will more effectively remove the oxide film from the surface, and the aluminum will be better seized by solder.

In industrial conditions, soldering of aluminum and its alloys is also performed with a conventional soldering iron using a flux consisting of a mixture of oleic acid and lithium iodide.

How to solder aluminum at home

• Chemical stripping methods
• Application of fluxes and solders

Aluminum and its alloys are only slightly inferior in strength to steel, but they are very easy to process, have a decent appearance and have excellent qualities such as thermal and electrical conductivity. However, along with these properties there is the difficulty of soldering them. The question of how to solder aluminum is asked not only by novice amateurs, but also by those who do not have difficulty soldering copper, brass and steel.

Soldering aluminum is a complex process, so you need to know all its technology.

Working with aluminum is not easy because of its ability to instantly oxidize in air, as a result of which the surface is covered with a thin film of Al2O3 oxide, which has increased resistance to aggressive environments. Therefore, special mercury fluxes or replacement tips for soldering irons are used, or, depending on the soldering method, the oxide is removed in various ways.

Before soldering aluminum, they resort to mechanical removal of the film, cleaning the work area with a file, but contact of aluminum with water or air leads to the original state - the appearance of the same film.

For soldering aluminum, you can use a special flux.

Experts advise cleaning the soldering area with a brick or sand, without removing the dust, but applying molten rosin directly to it, then rubbing it with a soldering iron, pressing firmly with the tip. This will help break down the thin film that formed before applying the rosin.

Also, the stripped aluminum is filled with rosin and sprinkled with filings from an iron nail obtained during the filing process. Next, you need to tin the surface with a soldering iron, carefully rubbing it with the tip. Iron chips will destroy the film, while rosin will prevent the formation of a new film.

Chemical stripping methods

It is important not to allow the aluminum being stripped to come into contact with air; for this purpose, the soldering area is filled with flux or rosin, while heating it. Often small elements, such as wires, are dropped directly into rosin or flux poured into a container.

In addition to the mechanical method of removing oxide, there are several so-called chemical methods.

Cleaning aluminum before soldering can be done using copper sulfate.

Cleaning with copper sulfate. The point where solder needs to be made is cleaned with a file and moistened with two or three drops of copper sulfate solution.

The aluminum base is connected to the negative pole of the battery or accumulator; a small piece of copper wire, stripped and connected to the positive pole, is lowered into the solution without touching the base.

After turning on the 4.5 volt battery, a copper coating forms on the aluminum after a short period of time. The desired part is then soldered to the dried copper.

Use of abrasive powder. A liquid paste is prepared by mixing powder and transformer oil, which is applied to the cleaned surface and then rubbed in with a soldering iron until a layer of tin appears.

Another method is transformer. The product is connected to its negative side, a copper wire containing several cores is connected to its positive side. After closing the circuit, microwelding of aluminum and copper will occur. To speed up the process, soldering acid is used.

  Do-it-yourself bumper repair soldering

Application of fluxes and solders

For soldering large parts, such as cooling radiators, soldering irons with high power (100-200 W) are used; soldering irons with a power of 60-100 W can handle small elements quite successfully. Of course, the solder area is not particularly strong, but this is not required.

At home, fluxes F-64, FTBf-A, and FIM are suitable for soldering aluminum. Of course, you can use aspirin, technical petroleum jelly, grease, solder fat, and stearin as a flux.

Using special active fluxes makes soldering easier; they cope well with the oxide film, provided that the heating temperature is 250-360°C.

The solder is distributed over the entire joint surface, resulting in a strong connection between the parts. Flux must be removed using solvents, alcohol or a special liquid. The convenience of using such fluxes is that they are also used for soldering nickel, copper and steel.

As a rule, alloys of 2 parts zinc and 8 parts tin, or 1 part copper and 99 parts tin, or 1 part bismuth and 30 parts tin are used for soldering aluminum. Conventional PIC solders. 40 and POS. 60 also copes with the task.

Small holes (no more than 7 mm in diameter) in aluminum cookware can be soldered without a soldering iron. The existing enamel around the hole should be beaten 5 mm by lightly tapping with a hammer.

Now you need to use a file or sandpaper to clean the metal until it shines, using rosin crumbs or soldering acid, put a piece of tin in the pan on the hole and heat it over an alcohol lamp, which provides spot heating without destroying the remaining enamel. The metal, melting, will completely close the hole.

So, if you have the desire, you can solder aluminum at home.

Kirill Nikolaevich Andreichenko

Before tinning a soldering iron, you should find out what this procedure is and why it needs to be carried out. The bottom line is that as a result of soldering, due to overheating, the soldering iron tip oxidizes and, accordingly, loses the ability to normally melt the solder.

Source: https://rem-serv.com/flyus-dlya-payki-alyuminiya-svoimi-rukami/

How to solder aluminum without argon

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

Flux

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://stoiportal.ru/kak-payat-alyuminij-bez-argona.html

Soldering aluminum with a gas torch

The need for soldering various parts arises both in domestic and industrial settings, since this process can be classified as minor repairs, although one often has to deal with larger-scale procedures. The fact is that various types and methods of metal welding cannot always provide results of decent quality, and are also not always suitable.

Therefore, soldering aluminum with a gas torch is a very popular method, which still has a number of its own features that beginners will have to master. The fact is that the solderability of this metal is not as good as that of other varieties, but soldering becomes more preferable, since when strongly heated, the metal changes its structure and welding spoils its properties, so welding cannot always be used.

To maintain quality, all available additional tools should be used, which are provided by the infrastructure developed over a long time.

Soldering aluminum with a gas torch

When working with aluminum, problems arise in the fight against the oxide film, which covers the metal in a relatively short period of time, so that it can appear even after pre-treatment.

Soldering with a torch is noticeably different from soldering with a soldering iron and is considered a more convenient process, since here you can regulate the temperature and the master gets more opportunities for delicate surface treatment, both thin and thick metal. Often at this time additional fluxes and various processing agents are used.

Soldering aluminum at home with a gas torch makes it easier to preheat the metal and melt additional consumables.

DIY aluminum soldering

Naturally, to obtain a high-quality connection, work experience is required, since aluminum is a low-melting metal, and accordingly, its solders have high spreadability. If done incorrectly, the material will simply spread over the surface, never filling the joint, let alone filling holes where real skill is required.

A very important point here is the selection of filler material, since each type of soldering requires its own solder. Aluminum can be used to create the body of a mechanism or any thick sealed container, as well as ordinary wires.

Soldering aluminum wires using a torch is easier due to convenient regulation of the flame temperature and its intensity.

Advantages

• Soldering aluminum with a torch is universal, unlike using a soldering iron, and can be used for both thin and thick parts;
• A gas burner has the ability to adjust the intensity of the flame, which determines the heating temperature, whereas when working with a soldering iron it is necessary to have several tools of varying power;
• With a burner you can heat the surface of the metal, melt solder and flux;
• The speed of work is slower, so it becomes possible to do everything more efficiently and calmly;
• The final results are higher quality than using a soldering iron;
• The tool is ready for use almost immediately and there is no need to wait long for it to cool down after work.

Flaws

• Preparation for work takes a longer period of time;
• The cost of the soldering process becomes higher;
• The work becomes less safe, since the container containing the gas may explode if exposed to an open source of fire, or the hoses may leak gas, which will also cause harm to the body;
• Equipment for the job is more expensive.

Materials and tools

• The main tool is a gas burner, which passes gas under pressure through itself. During combustion, it melts the solder metal and acts as the main heat treatment force. By adjusting the pressure supply, the overall flame temperature is determined.
• A container of gas, which can be represented by a small cylinder. There is consumable flammable material here, which must be reliably isolated from external influences.
• Hose for connecting the burner and cylinder. It itself, as well as the connections, should always be checked for integrity before use.
• Solder for soldering aluminum, which is selected according to the type of procedures with which there will be interaction. When soldering aluminum with a gas torch, the filler wire is selected according to the composition of the base metal.
• Flux to improve soldering properties. It is primarily used for thick workpieces, but is also used for brazing various types of metal, such as torch brazing of aluminum to steel, or particularly difficult cases.

"Important!

The melting point of the wire should always be lower than the melting point of the base metal.”

Step-by-step instruction

1. To begin with, the metal surface is prepared, for which purpose the surface of the part is pre-cleaned with a fine metal brush or sandpaper. You also need treatment with a solvent, which will help eliminate deposits of fat and oil, remove oxide film and other negative effects.
2. Then it is necessary to treat the entire surface where soldering will take place with flux. This will help improve the soldering properties, flow and wettability of the material.
3. Afterwards, you need to heat the workpiece with a burner so that the solder can better melt and spread over the surface.
4. After this, you can begin soldering by bringing the solder or filler wire to the surface of the workpiece and lighting the torch. By treating with a burner flame, melt the material so that it spreads over the surface and hardens there. Applying several layers can take place in several stages.
5. At the end, when the consumable material fills all the cracks and grooves, forming a smooth surface, you need to let it cool and check the quality of the connection.

Soldering aluminum with a torch

"Important!

If the thickness of the part is more than 4 mm, then you should start cutting the edges, since aluminum will not be soldered otherwise.”

Torch soldering modes

Workpiece thickness, mm	Solder consumption, g	Gas consumption, ml
1-2	0,5-1	3-5
2 -4	1-1,5	5,5
6	1,5	7
10	2	11

Safety precautions

Before each use of gas equipment, you need to check the integrity and proper operation of the gas cylinder, hoses and others. Cylinders should be kept as far as possible from open flames. There should be no flammable objects or flammable items near the workplace.

Source: https://svarkaipayka.ru/tehnologia/svarka-alyuminiya/payka-alyuminiya-gazovoy-gorelkoy.html

How to cook aluminum with argon

15.04.2019

There are several ways to permanently connect this capricious material; each has advantages and disadvantages. But reliable and aesthetic seams that do not require additional processing are created only by welding aluminum with argon. The success of the work is determined by the correct choice of equipment, consumables and knowledge of the nuances of the method.

Features of welding aluminum with argon

When performing work, you need to take into account the unusual characteristics of this metal:

1. Due to increased chemical activity, the surface of aluminum upon contact with air is quickly covered with an oxide film. It melts at a temperature of more than 2000⁰C, and metal - 660⁰C. If hard pieces of film get into the seam, its strength will decrease.
2. When welding aluminum, it is difficult to control the process, since its color does not change after melting.
3. The material is hygroscopic, therefore it absorbs atmospheric moisture, which, when heated, evaporates from the surface, reducing the quality of the connection.
4. Due to the high coefficient of linear expansion, the joint may become deformed and crack when cooling. To compensate for shrinkage, argon welding is carried out with increased wire consumption or the seam is modified.
5. If the gas flow is incorrectly adjusted when performing argon welding of aluminum, it foams when there is a shortage, and when there is an excess, it makes it difficult to form a seam.

Necessary equipment and materials

To operate, you will need a device that produces alternating current, since welding aluminum with direct current using the argon method cannot be carried out. The best option would be an inverter with a TIG mode and a set of options allowing:

• ignite an arc without contact;
• weld a crater at the end of the seam;
• adjust current balance;
• set the period of time during which the argon supply continues after the arc is turned off.

To reduce gas consumption for welding aluminum, you need to acquire a torch with a gas lens (collet holder), inside of which a mesh is placed. When argon passes through the cells, protection of the welding site is improved at lower consumption. To install lenses, nozzles of several diameters are available; the larger the size, the more reliable the protection.

Source: https://svarkaprosto.ru/tehnologii/kak-varit-alyuminij-argonom

Rod for soldering aluminum at home / Tools / iXBT Live

Hi all! Many people know that aluminum is soldered mainly in an argon atmosphere with a special welding machine, but there is also an option for working with a gas torch, and even a turbo lighter can be used on a small scale.

In general, this is not my first acquaintance with this wire, but the shopping experience is not very good, so I will share not only the test result, but also trusted places to buy so as not to get sample No. 2 , but let’s start in order.

• Characteristics
• Unboxing and appearance
• Testing
• Results

Characteristics

Diameter: 2.0 mm
Length: 500 mm
Soft solder ISO 3677: ~B-Zn98Al 381-400
Approximate composition (weight%): 2.4 Al – rest Zn
Melting point ºС: 360
Tensile strength (MPa): Up to 100 (Al)
Density (g/cm3): 7.0

Unboxing and appearance

The last and most profitable purchase was sample No. 3 from banggood.

Came in a small gray package

The rod is additionally packaged in a transparent zip bag.

5 meters cost me $8 with points, that is $1.6 per meter - go to the store

White powdery flux is visible in the center, the rod is moderately hard, looks like aluminum without oxidation

Comparison

The first one I bought was the leftmost sample No. 1 from Ali. Its properties are absolutely identical to sample No. 3 , but 3 meters cost me $12 , that is, $4 per meter , which is almost three times more expensive. check current price

In the center is sample No. 2 . It costs $5 for 3 meters or $1.7 per meter , like sample No. 3

But as soon as you take the bag in your hand, you realize that this is a POS with not very thick flux inside.

don't buy here

Two more samples at $8 for 3 meters were never delivered, they were probably not even sent.

Testing

Over time, aluminum becomes covered with an oxide film, due to which the surface becomes dull, so, before soldering, the surfaces must be cleaned to a shine, otherwise the solder will simply roll off in balls on the surface, regardless of the degree of its heating. Sample No. 1

 In general, it is correct to heat the part to a temperature of about 400 degrees, and then simply move the rod, which will melt and fill the cracks, but I have little experience, so in order not to overheat the surface, I periodically bring the rod into the burner flame. If the temperature is low, the solder will roll down the surface like a ball; if it is sufficiently high, it will tin it.

 The fracture test shows a good result - the break does not occur along the seam

Sample No. 2 . It melts very well, emits a lot of smoke, and smells like burnt “aspirin.” It sticks to aluminum, but if you overheat it, it burns out pretty quickly.

It is inconvenient to work due to the stench and the need to control the temperature.

Sample No. 3 . I decided to solder the tubes with the outer walls

We try to break the seam. After the tube came out of the vice, I clamped it higher, bringing it out of focus and only noticed this at the stage of creating GIFs

But there is a photo of the result which shows that the seam was not damaged.

And finally, let’s splice the aluminum tube with a piece of duralumin.

 The tear test was also successful.

Results

An interesting wire - aluminum solders perfectly, filling even small gaps, the main thing is that the joints are not dirty. It also sticks well to copper, but experienced people say that it is better to use other alloys to work with it, although this rod is quite suitable for emergency field repairs.

The melting point of aluminum is about 660ºC, it would seem that you can use rods at 450-500 degrees, but you may encounter two problems:
1. A massive part needs to be heated up to 500 degrees with something else
2. You can overheat the soldering area and ruin the part

Sample No. 3 seemed to me the most optimal .
It corresponds to the declared characteristics and costs at least half as much as the others. There are also lots of different lengths to choose from: 1 meter - $2.89
2 meters - $4.39
3 meters - $6.39
5 meters - $9.89

go to the store

Source: https://www.ixbt.com/live/instruments/prutok-dlya-payki-alyuminiya-v-domashnih-usloviyah.html

Do-it-yourself flux for welding aluminum

Before finding out why fluxes are needed during aluminum welding, let's look at what fluxes are and what their main area of ​​application is.

Welding flux is a material that is used to protect the welding area from atmospheric air, and also helps to form a high-quality weld and provides a more stable welding arc.

For example, during gas or forge welding of metals, materials such as boric acid, borax, fluorides and chlorides are widely used.

By using these fluxes, a liquid protective layer is formed in the welding area, which dissolves the oxides formed on the surfaces as a result of welding.

In this article we will try to educate you on the features of fluxes and, in addition, we will introduce you to the knowledge that is necessary in order to correctly use fluxes for welding aluminum.

Features of fluxes and their effect on aluminum

The main effect of fluxes during aluminum welding is based on the chemical processes of dissolving and washing off the oxide film with the help of molten flux components.

In order for the process to proceed efficiently and without damage to the base metal, electrode coatings are made with the same components as the fluxes themselves.

But, as a rule, the basis of fluxes is made up of low-melting mixtures of salts of alkaline earth and alkaline elements, plus a small amount of fluoride components, due to which the properties of the fluxes are activated.

Previously, scientists assumed that fluxes act on metals during welding in such a way that they only dissolve the oxide film due to the fluorides in their composition. But after some time, this axiom was questioned: the solubility in fluorides is not so high and, in addition, their content in fluxes is extremely small.

You can also remember that in pure sodium and potassium salts, which serve as the basis for fluxes during aluminum welding, the oxide of this metal is practically not subject to dissolution. But if you introduce cryolite into the flux components, the solubility of the oxide increases several times.

And here there are also some peculiarities - at 900 degrees Celsius, as well as when the flux contains 10% cryolite, the solubility of aluminum oxide in the flux is slightly more than 0.15%.

The principle of operation of fluxes during aluminum welding

During heating of the surface of the metals being welded and due to the different coefficients of thermal expansion of the film and metal, microcracks form in the oxide film. Molten flux, which contains chlorides, is poured into the resulting cracks.

Thus, the components interact, as a result of a chemical reaction, the compound AlCl3 or aluminum chloride is formed, which ignites at a temperature of 183 degrees Celsius.

These components have an important feature: at the point of contact between aluminum and liquid chloride, the latter partially tear off the film from the surface of the aluminum, and after that the particles of these two elements dissolve in the flux.

The well-known fact of the beneficial effect of fluorides, which are part of the flux, is that thanks to these chemical elements, the aluminum oxide film dissolves due to the fact that the fluorides enter the cracks in the film that form during heating of the metal surface. Thus, fluxes for aluminum welding gain easier access to the liquid metal under the oxide film and activate the process of its washing away and destruction.

As a result of the beneficial influence of fluorides and chlorides contained in fluxes, it becomes possible to form a high-quality weld on the surface of metals, bypassing the strong and elastic film of aluminum oxides. And thanks to fluxes, the surface of the weld remains clean from various impurities and oxidizing agents that can damage the structure of the seam.

Source: https://steelfactoryrus.com/flyus-dlya-svarki-alyuminiya-svoimi-rukami/

How to solder aluminum without argon: soldering method

The highest quality aluminum welding is argon arc welding. However, this method requires both expensive equipment and highly qualified welders, which often does not always correspond to reality. In addition, the equipment for this welding method is quite cumbersome and in some places its use is generally prohibited. In this article we will talk about alternative and inexpensive methods for welding aluminum without the use of argon.

Method 1: using Zeller 480 aluminum electrode

The Zeller 480 repair electrode with 12% silicon content is designed for welding a wide range of aluminum alloys including silumin and duralumin. This method allows you to reliably weld aluminum without the use of expensive argon arc equipment.

Benefits and Applications

• If the welding process is followed, the quality of the weld made using the Zeller 480 electrode is not inferior to argon arc welding;
• High surfacing productivity;
• Dense deposited metal without pores;
• Thanks to the soft, uniform arc, the seam is even and smooth;
• Zeller 480 is the only aluminum electrode available in a “low temperature” 2mm size;
• The electrode is equipped with a special protective coating, which is highly moisture resistant, which significantly extends the service life of the electrode;
• Welding is carried out without flux, since all the necessary elements for removing the oxide film are contained in the protective coating of the electrode;
• Used for welding aluminum sheets, profiles, busbars, tanks, aluminum castings, eliminating casting defects, crankcases, car bodies, etc.

Important! Since the coating of aluminum electrodes contains hygroscopic salts, after completing all welding work, the packaging should be hermetically sealed and stored in a dry, warm place.

Instructions for use

Step 1. Before starting welding, make sure that the prepared metal sample is dry, since aluminum is hygroscopic (absorbs moisture). Using a stainless brush, clean the joints to a metallic shine and remove any remaining dirt in the area around the seam.

Step 2. If necessary, dry the electrodes for 1-1.5 hours at 100°C.

Step 3. Heat the aluminum sample to a temperature of 150-200°C using a burner.

Important! Welding cannot be carried out without heating!

Step 4. Welding is carried out using direct current of reverse polarity. The most vertical position of the electrode while maintaining a short arc. The electrode should be fed into the fusion zone quickly, moving forward as much as possible and maintaining a very short arc.

Step 5: Weld one layer in one pass.

Be careful! The welding speed is the same as that of semi-automatic welding.

The tensile strength of the weld is 200 newtons per square millimeter, which is close to the tensile strength of the base metal. Therefore, this welding method can be used on critical structures.

Method 2: Using HTS-2000 or Castolin 192 solder

HTS-2000 or Castolin 192 solder is an alloy in the form of a zinc tube filled with solid flux powder in the center, which makes welding quick and easy. The solder is made using high technology and is specially designed to carry out work on the restoration of parts made of aluminum. At the same time, welding does not involve the use of high-cost technologies.

All you need to repair aluminum parts is just the solder itself and a gas torch for welding.

General recommendations for achieving the best results when working with solder

1. Clean the work surface immediately before applying solder.
2. You should not melt the solder in a torch flame, as this will prevent it from bonding to the metal. The solder must melt on its own on the surface of the part!
3. In the liquid state, solder is quite fluid, so it is worth tinning the surface well to eliminate the presence of cracks, especially at the soldering site.
4. Also make sure that the forming elements fit tightly together.
5. When applying solder, wait until it absorbs. Otherwise, sufficient adhesion of the metals will not occur, and, as a result, the required strength of the product will not be achieved.

Source: https://remboo.ru/dizajn/remeslo/kak-payat-alyuminij-bez-argona.html

Welding aluminum without a welding machine with a torch

If the project you are working on requires working with metal, you may want to use aluminum if appropriate. The reason is that you do not need welding equipment to weld aluminum parts. You just need a propane torch.

Aluminum is lightweight and strong enough to withstand light loads and deformations. Aluminum is also easy to work with because it is a soft metal, so you can cut it easily. You can do many things using aluminum, which you can also do with other metal materials.

How to "weld" aluminum without a welder - do it using the method shown in the video. The good thing about working with aluminum is that it requires a low melting point. This makes it easier to weld using only a propane torch.

Inventors shop at a budget Chinese online store.

Aluminum rods begin to melt at 700 degrees, making it an ideal welding material for joining aluminum parts. Many thanks to the presenter of “Diary of a Mechanic”.

Using a torch and Castalin solder is a quick way to join aluminum without welding. This makes a very strong connection and with a little practice can be done quickly with great results.

DIY electronics in a Chinese store.

Castalin solder is aluminum tubes that melt at 300-400 degrees. Flux inside.

The presenter made a small disclaimer. In fact, inside the solder there is a powder - flux.

How to solder aluminum

Until recently, I didn't know how easy it was to solder aluminum with a propane torch. The torch I use has a wide flame, so it's probably not as effective at heating up a specific area to weld. A torch with more points will be better. Either way, if you have a propane torch and soldering rods, you can weld aluminum. These can all be found at your local hardware store.  

Step 1: Buy the Right Aluminum Soldering Rod

In the same place where everything is designed for arc welding, you will find aluminum brazing. My rod has an operating temperature of 370 to 400 degrees Celsius. A propane torch burns hot enough to get the job done.

Step 2: Clean the parts at the joint

Any time metal is fused, it is always best that you clean it. I use a wire brush on both surfaces. Now the parts are ready for the heat.

Step 3: Soldering Aluminum

Source: https://izobreteniya.net/svarka-alyuminiya-bez-svarochnogo-apparata/

Soldering aluminum at home with a soldering iron and gas torch: solder and flux

Soldering aluminum is a rather difficult task. Basically, soldering aluminum parts becomes more difficult due to the appearance of a chemically resistant oxide on the metal surface.

In addition, due to the relatively low melting point and low temperature of loss of strength, it is quite difficult to heat aluminum without causing destruction of the entire product. Therefore, soldering aluminum parts is difficult if conventional consumables are used.

At the moment, soldering of aluminum products is carried out using specialized fluxes and solders.

Process Features

The key problems of soldering aluminum with traditional solders and fluxes are related to:

• the formation of an oxide film with a high melting point and good chemical resistance, preventing interaction with tin or lead solders;
• low melting point of pure metal, making high-quality soldering difficult.

To solder aluminum parts, specialists must clean the surface of the material from the oxide film or use specialized aggressive solders and fluxes.

Soldering aluminum with a soldering iron should be done using zinc solders. This option for low-temperature soldering of aluminum, unlike cadmium, bismuth, tin or indium, interacts well with pure metal and forms a strong seam.

Melting temperature of aluminum products for soldering.

The basic rules for soldering aluminum at home in the absence of zinc or aluminum solder include the following points:

1. Pre-cleaning of the surface.
   The area where soldering work needs to be performed should be carefully cleaned of paint, dirt and particles of other metals.
2. Grinding.
   For better adhesion between the solder and aluminum, the area of ​​the intended connection should be sanded.
3. You should not take a long break between cleaning aluminum and directly applying flux.
   Due to the high rate of oxide formation on the surface, the cleaning process for aluminum may need to be repeated.
4. The correct choice of device for heating the soldering area.
   Electric soldering irons with adjustable tip temperatures are ideal for this work.
5. Monitoring the temperature of the connection point.
   Due to the good thermal conductivity of the metal, the temperature will quickly spread over the entire area of ​​the product, and therefore the soldered area will quickly cool down.
6. A prerequisite for successful soldering of aluminum is tinning the area of ​​the intended contact.
   If a drop of solder is applied to the cleaned area of ​​aluminum in time, an oxide film will not be able to form.

There are several secrets that can be used to solder aluminum without specialized solder:

1. Destruction of the oxide film by intense friction of the joint with a brick.
   After a certain amount of dust has peeled off the stone, you should put the required amount of rosin or flux on the soldering iron tip and fill the soldering area. After this, you should make strong pressure movements with the flat cut of the soldering iron at the place of the planned soldering. With this simple action, brick dust will destroy the thin oxide film, and the solder on the soldering iron will tin the cleaned metal.
2. Destruction of the oxide film using iron particles.
   To do this, grind off a thick nail with a file, apply a large amount of liquid rosin or flux to the soldering area, and then add metal filings. After the soldering agent has hardened, you should put solder on the tip of the soldering iron and press it firmly into the soldering area.
3. Use of transformer oil.
   To implement this method, remove the top layer of the part with sandpaper, and then pour oil onto the cleaned area. After this, you can rub in the heated solder and get good adhesion between the tin and aluminum.

Necessary materials and available tools

Soldering of aluminum products with proper surface preparation can be performed with all types of solders. For example, soldering aluminum with tin is possible by removing the oxide film.

Materials required for soldering aluminum.

However, in most cases, aluminum joints obtained by soldering with tin solder have low reliability due to the poor solubility of the materials.

The most optimal solders for soldering aluminum are:

• zinc;
• copper;
• silicic;
• aluminum.

There are a large number of solders on the market based on the above materials. One of the most common zinc solders is TsOP40, which contains 40% zinc and 60% tin. In addition, 34A solder remains popular, consisting of 66% aluminum, 28% copper and 6% silicon.

Special mention should be made of special solder for low-temperature soldering of aluminum parts. One of the most common consumables for such an operation is HTS-200 solder.

Of course, we should not forget about the mandatory use of a special flux for low-temperature soldering of aluminum.

The flux for trouble-free soldering of aluminum must contain at least one of the following elements:

• triethanolamine;
• zinc fluoroborate;
• ammonium fluoroborate.

One of the brands of fluxes for welding aluminum with a gas torch is F64. The popularity of this flux is due to its high activity. Even aluminum parts can be soldered with F64 flux without first stripping the oxide film.

The F64 flux composition includes:

• 50% potassium chloride;
• 32% lithium chloride;
• 10% sodium fluoride;
• 8% zinc chloride.

Preparing parts

Soldering aluminum at home involves careful preparation of the part.

As a rule, qualified craftsmen perform the following procedures before soldering aluminum with their own hands:

1. Degreasing the surface.
   The most suitable substances for high-quality degreasing of the soldering area are acetone, gasoline and solvent.
2. Removing the oxide film.
   This procedure is carried out using a grinding machine or a homemade wire sponge. In rare cases, specialists use film etching using chemicals, such as acid.

After completing all the preparatory procedures, you can proceed to direct soldering of aluminum at home.

Technological approaches for aluminum soldering

The technology for soldering aluminum with flux is practically no different from joining other metals.

The entire process of soldering aluminum with solder can be divided into the following stages:

1. Surface preparation.
   Before soldering aluminum, the parts to be joined should be cleaned and degreased.
2. Installing the product into working position.
   This step may require a vice or a third hand.
3. Applying flux to the soldering area.
4. Warming up the product using an electric soldering iron or gas torch.
5. Apply solder or solder paste to the required areas.
   Zinc or copper solders are suitable for this role. Sometimes high-temperature solders may be needed to ensure good mechanical fixation of the product.

Scheme for soldering aluminum pipes.

It is important to remember that when soldering with flux-free solder, you should make striking movements with the soldering iron in order to ensure interaction between the components of the solder and the metal.

Carrying out work using a special soldering iron with a scraper will give good results in the following cases:

• soldering of aluminum utensils;
• soldering aluminum wires;
• seal surfaces not subject to strong mechanical loads;
• connection of small parts.

Soldering of massive aluminum parts and thick rods should be carried out using welding or a torch. Welding is not always suitable due to the high temperature of the arc, which melts the metal. Therefore, most specialists prefer to use burners.

The best effect is achieved with continuous soldering with a torch. If, for some reason, the soldering process had to be stopped, the entire seam should be completely heated in order to ensure uniform distribution of the solder and get rid of unsoldered areas.

The process of soldering aluminum rods using a torch is divided into the following stages:

1. Cleaning metal from dirt and preparing the surface by grinding.
2. Heating the entire surface of massive products using a burner.
3. Remove all flammable materials from the work area.
4. Turn on the hood to neutralize the caustic fumes of solder.
5. Preparation of solder wire.
6. Preparation of flux grades F-59A, F-61A or F-64A.

It is allowed to heat the metal to a bright orange color. In this form, the metal does not melt, and the solder is applied as evenly as possible.

The most complex and at the same time high-quality method of joining aluminum products is welding. This method is difficult due to the low melting point of the metal.

Qualified specialists most often weld aluminum products using the following methods:

• welding using coated electrodes;
• welding using shielding gas.

The first welding option has the following disadvantages:

• low weld strength;
• strong splashing of metal during cooking;
• poor separation of slag from the seam.

Welding in an inert gas atmosphere has no noticeable disadvantages and is considered the best method for joining aluminum parts.

Heating an aluminum product

The heating method for aluminum parts is selected individually. Products of relatively small sizes can be heated with an electric soldering iron and tinned with solder and flux for soldering copper. For more massive parts, it makes sense to use another method of soldering aluminum using a gas torch or blowtorch.

Table of solder brands for aluminum soldering.

When warming up the part, you should:

1. Control the temperature of the heated product.
   You can find out the current surface temperature of a part by touching it with a solder rod. When the aluminum solder wire begins to melt, reduce the heat and begin direct soldering using active flux.
2. Watch the burner flame.
   The burner jet contains a mixture of natural gas and oxygen, and therefore should be bright blue. The correct composition of the burner flame allows the aluminum part to oxidize less and not overheat.

The key advantages of heating massive aluminum products with a gas burner are presented:

1. Low cost of equipment.
   A gas burner consumes a small amount of fuel and is sold at any hardware store.
2. Absence of uneven heating and stress inside the product.
   Parts heated by a gas burner have an even seam and do not change geometry due to overheating.
3. Easy control of operating temperatures.
   If the metal heats up too much, reduce the intensity of the burner flame.
4. Possibility of soldering work at home.
   When the metal is heated with a burner, there is no pungent odor, there is no ultraviolet irradiation of the skin and no sparks fly.

Conclusion

Soldering aluminum with flux is a rather non-trivial task. When connecting aluminum products, certain standards must be observed, and the surface of the part must meet numerous requirements. If the technological process is not followed, the welded or soldered seam will crack and fall apart.

Aluminum welding technology depends on the massiveness of the product. Small parts, such as wires or dishes, can be easily repaired with an electric soldering iron, but large rods or pipes should be heated with a gas torch or blowtorch.

Source: https://tutsvarka.ru/vidy/pajka-alyuminiya

Soldering aluminum without argon

Home craftsmen quite often have to deal with the problem of repairs, as well as the manufacture of aluminum products. If there are no problems with mechanical processing (metal is easily sawed, turned and bent), then the process of connecting parts together causes difficulties.

We are not talking about welding, these are issues of large-scale repairs. Most often you have to solder parts in the traditional way.

• The most common problem is leaky dishes or parts of household aluminum utensils that have fallen off. Bonding is not always suitable due to low heat resistance and poor aesthetics of the seam. Rivets cannot provide a tight seal. All that remains is soldering aluminum with tin.
• Another need for a quality connection is electrical appliances. Quite often it is necessary to connect aluminum conductors to terminals, or simply to the surface of electrical equipment. Splicing wires will also be more reliable if there is a strong solder instead of twisting.

Like any metal, aluminum can and should be soldered. It has good ductility and thermal conductivity. But there is a problem with adhesion. In the open air, the metal is instantly covered with a durable film of oxides, which not only acts as a heat insulator, but it is almost impossible to apply solder to it.

Therefore, high-quality flux for soldering aluminum is the first assistant in your work. With its help, you can also solder aluminum to other metals.

General principles of soldering aluminum at home

1. The surface must be thoroughly cleaned of paint, dirt and greasy liquids
2. The soldering area is ground, it is advisable to level out all irregularities to the depth of the largest defect
3. There should be a minimum amount of time between cleaning and applying flux.
4. It is necessary to choose the right heating device according to the volume of metal
5. Aluminum has excellent thermal conductivity, the temperature is dissipated over the entire area, and the heated area will quickly cool down
6. Before soldering, aluminum must be tinned. No oxides are formed under the solder layer.

Little secrets. If you don’t have a special flux on hand, you can use abrasive protection against immediate surface oxidation:

• Rub the soldering area vigorously with a piece of brick. The resulting dust does not need to be blown off. Place a large amount of regular rosin on the soldering iron tip and pour it over the soldering area directly on top of the brick dust. Then tin the surface by pressing the soldering iron tip firmly onto the metal. Use a flat cut to rub the dust into the aluminum. The abrasive will remove the thin layer of oxide and provide a bond to the solder. You can use sifted fine sand.
• Another way is to use iron filings. You can simply file down a thick nail with a medium-grit file. Pour liquid rosin onto the soldering area and cover it with sawdust. When the rosin hardens, put solder on the tip of the soldering iron and intensively rub it on top of the sawdust. The tin coating will provide instant protection against oxidation.

  Thermal conductivity of titanium and aluminum

Use of transformer oil

Soldering aluminum at home is usually done with a soldering iron.

You can mix solder paste with transformer oil and apply it to the newly cleaned surface. Then rub the soldering iron vigorously until a stable layer of solder appears.

But there is an easier way. We process the future soldering area using fine sandpaper. Then, without delay, pour in the oil.

Once again, intensively rub the surface with sandpaper, after which we rub in the solder with force with a heated soldering iron.

We pry up the tin layer with a thin screwdriver to check the strength of the connection. If the edges of the solder come off the aluminum, repeat the procedure again. After obtaining stable tinning, both copper and aluminum wires can be soldered to this place.

What kind of solder is used for soldering aluminum?

The choice of solder is influenced by the method of joining aluminum parts.

1. If you are using a regular soldering iron, you need a material with a low melting point. Electrical connections typically use traditional solder. These are the following types of alloys: zinc-tin, copper-tin and bismuth-tin. They are better known to us as amateur radio solders of the POS series.

   These alloys melt easily, and little heat from the soldering iron is transferred to them (which is important, given the high thermal conductivity of aluminum). In addition, such material is easy to buy at an affordable price. However, connections using low-melting solder have low strength. This method is only suitable for electrical installation.

   If you soldered the spout to an aluminum kettle, or repaired a burnt hole in a pan, the connection will quickly collapse under the influence of high temperatures.

   As a last resort, you can use the common refractory solder TsOP-40, consisting of tin and zinc. This connection holds the temperature quite well, but has low tensile strength.

2. For mechanically strong connections, refractory solders are used. In addition, they will not melt at high temperatures. The composition must necessarily include aluminum itself.
   The most common alloys are aluminum-copper-silicon.

   Aluminum dissolves well in the other components of the composition, and will provide a connection with the workpiece at the molecular level. Copper will add ductility, and silicon will make the connection strong. The favorite solder of home tinkers is domestic composition 34A.

More expensive (this does not mean an increase in quality) is the imported “Aluminum - 13”. The advantages of such solders are that they can be used to qualitatively weld parts, which then work under load.

Of course, these solders do not reach the strength of arc welding, but repairing dishes with their help gives a good result.

However, aluminum-based solders melt at a temperature of about 600° C. This result cannot be achieved using a soldering iron.

For mechanically strong and heat-resistant connections, aluminum is soldered with a gas torch.

Despite the external similarity and quality of the connection, soldering with a torch has nothing in common with welding. Only the solder melts; the base metal of the workpiece remains solid during the entire process.

  Reduction of silver with aluminum

Advantages of soldering with a torch over welding in an argon environment:

1. There is no need to purchase expensive equipment. A hand-held gas torch is used for soldering. Such a tool can be purchased in tool stores, or even among tourist goods.
2. Electric welding, using any method, exposes the material to thermal stress. Foci of different tension in the metal appear; near the seam, the aluminum changes geometry. With high-quality soldering, the aesthetics of the connection remains at a high level
3. For connecting compact parts, especially those made of thin metal, there is simply no alternative to soldering
4. The work can be done at home - no sparks fly, no pungent smell of burning aluminum, no ultraviolet irradiation of the skin
5. You can easily control temperature conditions during operation by simply changing the intensity of the flame.

How to solder correctly using a torch

You cannot do without preparing the joint, just like when soldering with a soldering iron. The metal should be cleaned of dirt and sanded to obtain a smooth surface. Then you need to secure the parts using any jig - be it clamps or a vice.

When working with a burner, aluminum blanks will heat up over the entire surface. And given the high thermal conductivity of metal, there will simply be no place on the parts that you can grab with your hand, even with protective gloves.

The work area must be cleared of flammable objects and liquids. Provide intensive ventilation - even without caustic emissions, heated fluxes emit an unpleasant odor. Take care of fire extinguishing equipment.

It is necessary to prepare solder wire with a margin of length. You won't be able to use every rod completely; there is 10% of the length left to hold the solder. But stopping heating and going for new packaging is irrational.

The burner flame is always directed away from you. There should be no objects in its path.

It is allowed to change the color of the aluminum billet to bright orange. The metal will not melt, and when heated to the maximum temperature, the solder will lie more evenly.

Be sure to use flux. There are proven compositions based on lithium and potassium chlorides, as well as zinc chloride. These are brands such as F-59A, F-61A, F-64A. For higher temperature soldering it is better to use F-34A. It contains sodium fluoride.

You can prepare flux for soldering aluminum yourself. However, this is not recommended, since it necessarily contains caustic substances. It is better to purchase a ready-made composition in the store.

Popular: Pneumatic jack - how does it work and what are the advantages?

Source: https://varimtutru.com/payka-alyuminiya-bez-argona/

Soldering aluminum at home: features of the process, types of flux and solders, how to solder a pipe

Aluminum and its alloys have very good characteristics, such as high thermal and electrical conductivity, ease of processing, low weight, and environmental safety. But this beautiful metal has one very big drawback: it is extremely difficult to solder. A properly selected flux for soldering aluminum helps solve this serious problem.

The problem with soldering aluminum is due to its chemical structure. This metal itself is chemically very active; it reacts with almost all chemicals.

This causes pure aluminum to instantly react with oxygen in air. As a result, a very thin and at the same time extremely strong oxide film is formed on the metal surface: Al2O3.

In terms of their properties, aluminum and its oxide represent two extreme opposites combined into a single whole. For example :

• The melting point of pure aluminum is 660 degrees. Aluminum oxide, or corundum as it is also called, melts at a temperature of 2600 degrees. Refractory corundum is used in industry as a refractory material.
• Aluminum is a very soft and ductile metal. Corundum has extremely high mechanical strength, which makes it possible to produce all kinds of abrasive materials from it.

Aluminum oxide turns ordinary soldering into a rather complex process. For its successful implementation, it is necessary to use specific methods and special aluminum solders and fluxes.

Metal soldering

The meaning of soldering any metal is that a special substance called solder is introduced into the space between the parts being soldered in a molten state. After hardening, the solder reliably binds two metal parts into a single whole.

When soldering aluminum, the oxide film on its surface prevents the molten solder from connecting to the metal. In other words, adhesion is impaired, and therefore the solder cannot spread over the surface of the metal and stick to it . This makes soldering aluminum almost impossible without the use of special means that partially remove the oxide from the metal surface and promote normal adhesion.

Removing oxide film

Removing oxide from the surface of aluminum is a complex process and never leads to a final result. That is, the oxide film is practically impossible to remove, since instead of the one just removed, a new one is instantly formed. It is possible only with the help of specific means to weaken its effect. This can be done using two different methods :

• Chemical method. With the help of special aluminum fluxes, the film is destroyed as a result of exposure to active acids.
• Mechanical method. Through the use of abrasive tools, the integrity of the film is damaged.

In practice, both of these methods are most often combined to achieve the maximum possible effect.

Fluxes for aluminum

Flux is used to remove oxide from the metal surface and subsequently prevent the formation of a new film. It must be remembered that during the soldering process, the flux should not interact with the solder and enter into chemical reactions with it. Fluxes can be in different states :

• Liquid.
• Paste.
• Powder.

For aluminum, liquid fluxes based on orthophosphoric acid are most often used . There are so-called no-clean fluxes, the use of which does not require subsequent washing of the soldered surfaces under running water.

However, most often aluminum fluxes contain highly toxic substances that are unsafe and, from an environmental point of view, can severely corrode the metal at the soldering site. Therefore, the use of fluxes requires thorough washing of the soldering area under running water.

The industry produces a larger number of aluminum fluxes, among which the following can be distinguished::

• F-64. Highly active flux for aluminum and its alloys. It is considered the best flux for this metal. High activity is determined by the high content of active fluorine in its composition, about 40%. When heated, fluorine destroys the oxide film on the surface of aluminum. The use of this flux requires thorough washing of the welded surfaces after the process is completed.
• F-34A. Special aluminum flux for refractory solders. Ingredients: potassium chloride 50%, lithium chloride 32%, sodium fluoride 10%, zinc chloride 8%.
• F-61A. It is used with conventional lead-tin solders, melting at a temperature of 150−350 degrees. Composition: zinc fluoroborate 10%, ammonium fluoroborate 8%, triethanolamine 82%. Used for soldering dissimilar metals, such as aluminum and copper. Therefore, when the question arises of how to solder aluminum to copper, this flux will be the answer.
• NITI-18 (F-380). Suitable for refractory solders with a melting point of 390 - 620 degrees. The peculiarity of this flux is that, while dissolving the oxide film well, it has virtually no effect on the base metal. After finishing soldering, flux residues must be removed immediately. To do this, the soldering area is first washed with hot running water, then with cold water. And finally, incubate for 15 minutes in an aqueous solution of phosphoric anhydride.
• A-214. Universal no-clean flux of medium activity. Application temperature 150−400 degrees. It does not contain harmful salts of aniline, phenol or carboxylic acids, therefore, thorough rinsing is not required after use. Residues can be easily removed with a paper towel soaked in alcohol.

Mechanical oxide removal

To facilitate the dissolution of the film using flux, it is first partially removed using mechanical methods. These techniques make it possible to only slightly weaken the effect of the oxide, since it was experimentally established that the newly formed film is somewhat inferior in strength characteristics to the old one. For these purposes the following devices are used :

• Sandpaper.
• Files and rasps.
• Hard metal brushes.

The process of mechanical removal of surface oxide can be optimized using brick dust. The soldering area is first sprinkled with fine brick chips . Then:

• A large amount of dry rosin is poured onto the brick crumbs.
• With a preheated soldering iron tip, the rosin is melted and distributed over the metal surface in an even layer.
• With the tinned tip of the soldering iron, they begin to vigorously rub the soldering area. In this case, the brick chips peel off the oxide film, and the molten rosin prevents the penetration of oxygen instead of soldering and therefore a new oxide film does not form.
• The result is a well-tinned aluminum surface.

As an abrasive, with the same effect, you can use sifted river sand or metal filings.

Soldering aluminum

The basis of any soldering is the so-called tinning or tinning. In this process, solder is distributed evenly over the surface of the metal. In order for tinning to go well, two important components are needed: a special flux and properly selected solder. We have already looked at fluxes, now it’s the turn for solders.

Special solders

Conventional solders used for soldering non-ferrous metals contain tin and lead. The question of how to solder aluminum with tin is not relevant, since such solders are not recommended for aluminum, because it is practically insoluble in these metals. Special solders are used that contain a fair amount of aluminum itself, as well as silicon, copper, silver and zinc.

• 34-A. Special refractory solder for aluminum. Melting point 530−550 degrees. Composition: aluminum 66%, copper 28%, silicon 6%. It is recommended to use it together with the corresponding flux F-34A.
• TsOP-40. Belongs to the category of tin-zinc solders. Composition: zinc 63%, tin 36%. Melting occurs within 300−320 degrees.
• HTS 2000. Special solder for aluminum made in the USA. Main components: zinc 97% and copper 3%. Melting point 300 degrees. Provides a very strong connection, comparable in strength to a weld seam.

The presence of a metal such as zinc in the solder provides it with high strength characteristics and good resistance to corrosion. The presence of copper and aluminum increases the melting point and makes the solder refractory.

The use of one or another solder is determined by the tasks facing the parts being soldered. Thus, for soldering large-sized and massive aluminum parts, which will subsequently be subjected to heavy loads, it is better to use refractory solders; their melting temperature is comparable to the melting temperature of aluminum itself.

When the question arises of how to solder an aluminum tube, you need to understand exactly what this tube will be used for in the future. Refractory solders are characterized by high strength, and the large mass of the part allows for good heat dissipation during the soldering process, which will prevent the destruction of the aluminum structure due to its melting.