How to tin an aluminum wire. Soldering aluminum at home with a soldering iron and torch. Sequence of work

Hello my dear readers! I became interested in aluminum soldering about 5 years ago, when I urgently had to solder the cooling radiator of my Grasshopper. Below I will show a photo of it and the place of soldering on the radiator, which is still working. Recently I was asked what is the best way to solder aluminum? I decided to read all the relevant articles and personal opinions on aluminum soldering and put it on one page. This is how this article was born. Go!

Why is aluminum difficult to solder?

Anyone who has tried to solder aluminum knows that ordinary solder does not stick to it at all. This is all due to a stable film of aluminum oxide, which has poor adhesion to solder. Moreover, this film covers aluminum and its alloys very quickly. Before you have time to clean it, the light metal has already oxidized. Therefore, all methods of aluminum soldering first deal with the film, and then take care of adhesion.

Aluminum oxide (Al 2 O 3) in mineralogy is called corundum. Large transparent corundum crystals are precious stones. Due to impurities, corundum is colored different colors: Red corundum (containing chromium impurities) is called ruby, and blue is called sapphire. Now it is clear why the oxide film does not solder at all.

How to remove oxide film?

The aluminum oxide film is removed in two ways: mechanical and chemical. Both methods remove aluminum oxide in an airless environment, that is, without access to oxygen. Let's start with the most difficult, but most correct and reliable method of removal - chemical.

Precipitate copper or zinc

The chemical soldering method is based on the preliminary deposition of copper or zinc onto aluminum by electrolysis. To do this, apply a concentrated solution of copper sulfate to the desired location and connect the negative of the battery or laboratory power source in a free place. Then take a piece of copper (zinc) wire, connect a plus to it and immerse it in the solution.

Through the process of electrolysis, copper (zinc) is deposited onto the aluminum and adheres to it at a molecular level. Then aluminum is soldered on top of the copper. True, it is not clear how all this passes through the oxide barrier. I think that this instruction skips the step of scratching aluminum under a film of copper sulfate or other chemical exposure. Although the practice from the video below shows that you don’t have to scratch.

Use oil without water

The second most difficult method is to remove aluminum oxide. In this case, the oil should contain a minimum of water - transformer or synthetic oil will do. You can hold the oil at a temperature of 150 - 200 degrees for several minutes so that the water evaporates from it and it does not splash when heated.

Under the oil film, you also need to remove the oxide. You can rub it with sandpaper, scratch it with a scalpel, or use a serrated tip. When I needed to solder the engine cooling radiator, I used the chip method. We take a nail, saw it with a file to get steel shavings.

Next, apply oil to the soldering area and sprinkle chips. Using a soldering iron with a wide tip, we try to rub the soldering area so that there are shavings between the tip and the aluminum. In the case of a massive radiator, I additionally heated the tinning area.

Then we take a drop of solder onto the tip, immerse it in oil at the soldering site and rub it again. For better tinning, you can add rosin or other flux. The so-called surfacing under a layer of flux occurs. The video shows a good example of soldering aluminum with oil.

Solder with active flux

There are separately developed active fluxes for soldering aluminum. They usually contain acids (orthophosphoric acid, acetylsalicylic acid) and salts (sodium salt of boric acid). Strictly speaking, rosin also consists of organic acids, but in practice it gives a weak result on aluminum.

Due to their activity, acid fluxes must be washed off after soldering. After the first wash, you can additionally neutralize the acid with alkali (soda solution) and wash it a second time.

Active fluxes give good and quick results, but inhaling the vapors of this flux is strictly prohibited. Vapors irritate mucous membranes, damage them, or can enter the bloodstream through the respiratory tract.

Fluxes for aluminum soldering

Let's look at all the common fluxes for soldering aluminum.

Rosin

Liquid fluxes are good because they can be applied in a thin layer. They evaporate more actively and often have scalding vapors. More suitable for soldering with a soldering iron.

• Flux F-64 contains tetraethylammonium, fluorides, deionized water, wetting additives and corrosion inhibitors . It is capable of destroying a strong oxide film of considerable thickness, which means it is suitable for soldering large workpieces. Suitable for soldering aluminum, galvanized iron, copper, beryllium bronze, etc.
• Flux F-61 contains triethanolamine, zinc fluoroborate, ammonium fluoroborate. It can be recommended for low-temperature soldering at 250 degrees or tinning of products made of aluminum alloys.
• Castolin Alutin 51 L contains 32% tin, lead and cadmium. This composition works best when using solders from the same manufacturer at temperatures of 160 degrees and above.
• There are also, but I won’t list them - they should all be equally good.

Solder for soldering aluminum

Solder HTS-2000

This is the most advertised solder. Soldering aluminum with it is very simple. Watch the promotional video about soldering HTS-2000 from New Technology Products (USA). They say it is even better and stronger than aluminum. But it is not exactly.

Castolin solder

Solder Castolin 192FBK consists of aluminum 2% and zinc 97%. 192FBK is practically the only solder for soldering aluminum to aluminum in the list of offers of the French company Castolin. There is also AluFlam solder 190, but it is designed for capillary soldering and does not have flux inside. The line also includes Castolin 1827 solder, designed for soldering aluminum with copper at a temperature of about 280 degrees.

Castolin 192fbk tubular solder contains flux in the core, so you can solder without the recommended Castolin Alutin 51 L liquid flux. The video below shows the soldering process. Good solder - you can buy it for 100 - 150 rubles. per rod weighing 10 grams.

Solder Chemet

Solder Chemet Aluminum 13 used for welding aluminum and its alloys with a melting point above 640 degrees. It consists of 87% aluminum and 13% silicon. The solder itself melts at a temperature of about 600 degrees. Cost - about 500 rubles. for 100 grams, in which there are as many as 25 rods.

Its older brother Chemet Aluminum 13-UF has flux inside the tube, but costs more - 700 rubles. for 100 grams and 12 rods.

I didn’t find any sane videos on soldering with this solder. Of course, this list of solders is not exhaustive. There are also Harris-52, Al-220, POTs-80, etc.

Domestic solders

• • . Why not? When I was soldering an aluminum radiator, this was the only one I had on hand. And it has held up well for 5 years.
  • Aluminum solder 34A- for soldering with a gas-flame torch, in a furnace in a vacuum or with immersion in a melt of aluminum salts and its alloys, except for D16 and containing > 3% Mg. Melts at 525 degrees. Solders aluminum alloys AMts, AMg2, AM3M well. For 100 grams you will have to pay about 700 rubles.
  • Solder grade A— manufactured in accordance with TU 48-21-71-89 and consists of 60% zinc, 36% tin and 2% copper. Melts at a temperature of 425 °C. 1 rod weighs about 145 grams and costs about 400 rubles.
  • SUPER A+ used with SUPER FA flux and manufactured in Novosibirsk. Positioned as an analogue of HTS-2000. For 100 grams of solder they ask for about 800 rubles. There are no reviews yet.

Comparison of solders for aluminum soldering

In this video, the Master compared HTS-2000 solder with Castolin 192fbk and domestic aluminum solder “Aluminum Cucumber”. The cucumber is practically made of aluminum, so its strength is high, but it must be soldered in a stove. Reviews of HTS-200 solder are extremely negative, but Castolin 192fbk solders well and has good wettability when heated.

The results are:

• HTS 2000- solder is malleable, you have to resort to steel tools to level the solder over the metal surface. The situation with flux is much better.
• Castolyn 192FBK- high fluidity and wicking. Small holes are soldered with it quickly. It is difficult for them to solder large holes - it may fall inside the radiator.

Cored wire

Flux cored wire - needed for welding aluminum, not for soldering. Don't confuse these two concepts. The advantage of this wire is welding without the use of gas. This is electric welding for aluminum. An interesting thing, but expensive. I'll show you a good video about flux-cored wire welding.

Soldering iron for soldering aluminum

Soldering aluminum using a soldering iron must take into account the area of ​​the parts being soldered. Aluminum, like copper, is a good conductor of heat, which means more heat should come from the soldering iron than the parts being soldered dissipate.

An approximate calculation is 1000 sq. cm aluminum can effectively dissipate about 50 W of thermal power. It turns out to solder two parts with a total area of ​​1000 square meters. cm, you need to take at least. Then soldering aluminum will be fast enough so as not to turn into torture.

You can also solder with a low-power soldering iron. For example, when I soldered the radiator of my Grasshopper with a 60 W soldering iron, a hot air gun helped me Soldering Station, which served as heating.

Aluminum soldering torches

When the power of the soldering iron and heating are not enough to solder, for example, thick aluminum sheets, then they come to the rescue.

I have already written a separate article about burners -. The power and size of the burner nozzle also depends on the areas that need to be heated. The advantage of a heating pad is the contactless delivery of heat and high speed warming up Often the edges of the workpiece do not have time to heat up, and the joint is already soldered.

Observe safety precautions when working with burners!

Here's what you can do with a simple canister torch.

What is better - welding or soldering aluminum?

The debate over the answer to this question is not going to subside. It turns out it all depends on your purpose. More precisely, the purpose of your connected parts.

If you need to solder a car radiator, then soldering aluminum is better suited because it is cheaper. For critical work (load-bearing structures) and food containers (for example, a milk flask), welding is better suited because it is more reliable. This is how I would formulate the answer to this question.

It is clear that it is easier for a master with gas welding to weld a radiator, rather than solder it, and vice versa - it is easier for a master with a soldering iron to solder.

Now look at TIG welding for beginners. Very helpful and well filmed.

How to make money soldering aluminum?

And now the most interesting thing is how and how much to earn from soldering aluminum. I opened Avito and searched cost of aluminum soldering work. Here's what happened:

• soldering of a car radiator, refrigerator, air conditioner - from 1000 rubles.
• soldering of electrical wiring - 15 rubles. for soldering.
• repair of bicycle frames - from 500 rubles.
• soldering of aluminum for food, for example, pans - from 100 rubles.

Expenses:

• Gas cartridge with burner 700 - 1000 rubles.
• Solder Castolin 192FBK - 150 rub. per bar * 5 = 750 rub.
• Training radiator - free or for 500 rubles. in scrap metal.
• Desire is priceless!

Business plan:

1. Spend 2000 rubles. for tools and experience
2. Recover the costs for 2 repairs.
3. There will still be at least 3-4 repairs left.
4. Profitability 200 - 300%!

And now what was promised. This is what my radiator looked like.

At this point, the fan casing bent due to heat and began to rub against the radiator. Three holes formed through which antifreeze leaked. I remember this night. It's good that it was within the city limits.

In all Rostov region I've only seen one machine like this. Once in the city of Kamensk-Shakhtinsky, she and I stood at a traffic light one behind the other. It looked funny.

That's all. I hope that now soldering aluminum is not something special for you. Master Soldering worked for you. What do you use to solder aluminum?

The opinion that it is very difficult to solder elements made of aluminum or alloys based on it is largely erroneous. Of course, if you use for this purpose compositions intended for working with copper, brass or steel, then you will get positive result almost impossible. Special solders for soldering aluminum will greatly simplify this process.

and alloys based on it

The difficulties that arise when soldering aluminum are due to its specific features:

• high resistance of the oxide film on the surface;
• low melting point;
• high heat capacity.

Based on the temperatures at which aluminum is soldered, there are two main methods:

• low temperature in the range of 150-300⁰С (soft soldering);
• high temperature - 390-580⁰С (hard soldering).

Taking into account the characteristics of the metal, manufacturers have developed special solders and fluxes for soldering aluminum.

Advantages of soldering

Previously, special argon welding was used to connect aluminum parts. To carry out such work, expensive equipment was needed, and only a highly qualified specialist could use it. In addition, at the welding site, the metal was destroyed in depth.

Soldering aluminum with solders and fluxes is free from all of the above disadvantages and has a number of advantages:

• Available devices are used to fasten parts together.
• The work can be carried out even by an unqualified performer, that is, it is quite possible to do it yourself at home.
• The integrity and structure of the connected parts is not compromised.
• If the soldering technology is followed correctly, the mechanical strength of the connection is not inferior to welding seams.
• Reheating makes it easy to change mutual arrangement parts and soldering points.

Soldering aluminum at high temperatures

In order to firmly connect sufficiently large aluminum elements, so-called hard soldering is used. For this you will need:

• gas-burner;
• metal brush;
• solder.

The work algorithm is quite simple:

• In the soldering areas, carefully clean the parts using a steel brush.

• We heat the joint of the parts using a gas burner to the melting temperature of the solder (for modern compositions this is usually 390-400⁰C).

• We press the solder rod tightly to the soldering site and apply it to the surface with a back-and-forth motion.
• Use a steel brush to remove the oxide film under the molten solder.
• Let the parts cool naturally.

Brazing Solders

For a long time, only 34A solder was available to Russian consumers. The main component of this composition is aluminum (up to 66%). Soldering temperature is 530-550⁰С. You must work with it with extreme caution so as not to melt or damage the parts being fastened, because the melting of aluminum itself begins at 660⁰C. In addition, when carrying out work, according to the manufacturer’s recommendation, the solder bar must be periodically dipped in F-34A flux.

The temperature for soldering aluminum with HTS-2000 solder (American-made) is about 400 degrees. The elements are connected without the use of flux. This greatly simplifies the technological process.

Another fairly popular and widespread solder with a flux core is the Swiss Castolin 192 FBK. Its soldering temperature is slightly higher - 440 degrees. The presence of flux in the structure of the rod facilitates the removal of the oxide film from the surface and ensures reliable adhesion of the solder to aluminum.

Both of the above-described imported compounds are made on the basis of zinc, so the soldering area has high anti-corrosion properties.

Recently, foreign manufacturers have acquired a worthy competitor - “Super A+” solder for aluminum soldering, which was developed and is now manufactured in Novosibirsk. According to their own technical specifications it is in no way inferior to its Western counterparts. The hard soldering process is carried out at the same 400 degrees acceptable for metal. Moreover, there is no need to use flux. But its price is much lower (2-3 times) than its Western counterparts. The developers have prudently not yet published the composition of the ingredients.

Soldering aluminum at low temperatures

Since soft soldering is usually carried out at temperatures in the range of 230-300 ⁰C, it will require:

• electric soldering iron;
• solder for soldering aluminum;
• flux;
• convenient tools for cleaning parts (wire brush, file or sandpaper).

Work order:

• We clean the parts to be connected using any mechanical method.
• We fix them in the desired position.
• Apply flux to the soldering area (for example, with a brush).
• We press the tip of the (preheated) soldering iron and the solder rod into the joint.
• The solder begins to melt. Moving the soldering iron forward, we solder the entire seam of the connection.

• Let the fastened parts cool.
• We carefully clean the soldering area from flux residues (for example, with a napkin or rag soaked in alcohol).

Solders for soft soldering of aluminum

For low-temperature soldering of aluminum, compounds from a variety of manufacturers are currently used. Many people successfully solder aluminum using Russian-made P250a solder. It is made on a tin base (80%). It also contains zinc (19.85%) and minor copper additives (0.15%). The low price and availability of purchase ensured its sufficient popularity.

Swiss solder Castolin 1827 for soldering aluminum is also quite common in our country. It contains silver, cadmium and zinc. However, its price is much higher Russian analogue. In addition, manufacturers strongly recommend using it only with fluxes of their own production.

Fluxes for aluminum soldering

Fluxes dissolve and remove the oxide film from the metal surface, and also promote better spreadability of the molten solder, which ultimately affects the quality and strength of the connection. Therefore, they must be selected as carefully as solders for soldering aluminum.

Russian manufacturers (SmolTechnoKhim, Connector, Rexant, Zubr) offer two main types of liquid active fluxes: F-59A and F-61A. The letter index “A” in the marking means that their composition is designed specifically for soldering aluminum, alloys based on it, as well as combined compounds with copper, steel and other metals.

Among the imported liquid fluxes for soft soldering, the Russian user is most familiar with the Swiss Castolin AluTin 51. The carefully developed and well-balanced composition is suitable both for soldering aluminum elements and in combination with other metals.

All of the fluxes listed above are intended for low-temperature soldering (in the range from 150 to 300 degrees). Hard soldering of aluminum is carried out mainly either without the use of fluxes, or its components are built into the structure of the solder rod.

Finally

From all of the above, we can draw an unambiguous conclusion: the process of soldering aluminum elements is quite simple and accessible to everyone. Knowing what supplies to buy and what tools to use can help you solder aluminum electrical wires together or repair a cracked oil pan. automatic transmission transmission

Craftsmen have no difficulty soldering copper, brass and steel wires and parts, but if they have to deal with aluminum surfaces, the solder does not even stick to the product, and soldering turns into torture. The difficulties are caused by the fact that a thin but very strong film of Al2O3 oxide forms on the surface of this metal. You can remove this film mechanically - for example, by cleaning the product with a file, but upon contact with air or water, the metal will immediately become covered with a film again.

Despite the difficulties that arise, it is possible to solder aluminum products. There are several ways to solder aluminum.

Soldering aluminum alloys

Excellent results can be obtained using the following alloys:

• two parts zinc and eight parts tin
• one part copper and 99 parts tin
• one part bismuth and 30 parts tin

Before soldering, both the alloy and the part itself must be well heated. It should also be remembered that soldering acid must be used with this soldering method.

Soldering aluminum using special fluxes

Standardly used fluxes do not dissolve the oxide film on the surface of aluminum, so special active fluxes must be used.

Flux for soldering aluminum is used to work with tin-lead solders at an operating temperature of 250-360 degrees. This flux, both during soldering and tinning, removes the oxide film well, cleans the metal surface and, as a result, the solder spreads better over the surface. All this leads to the creation of a more dense and durable connection of the fused parts. Excess of this flux is easily removed with solvents, alcohol or special liquids.

Other methods of soldering aluminum

There are also non-standard ways to solve this problem, for example:

• The soldering area on the aluminum product is thoroughly cleaned and a couple of drops of concentrated copper sulfate are applied. A small piece of copper wire is stripped, rolled into a circle with a diameter equal to the soldering area, and the free end of the wire is connected to the “plus” terminal of the 4.5 volt battery. A piece of wire with a folded circle is dipped in a small amount of copper sulfate. The negative of the battery must be connected to a part on which, after some time, a certain layer of copper will settle. After drying, you can weld the necessary parts or wires to this place in the usual way.
• In this case, abrasive powder is used, mixed with a small amount of transformer oil to form a liquid paste. This paste is applied to cleaned soldering products. Next, the soldering iron is well tinned and rubbed in these places until a layer of tin is released on the surface. Then the parts are washed and then soldered using the usual method.
• For this method you will need a transformer. Its minus is connected to the product, and a large-section copper wire consisting of smaller conductors is connected to the plus. If you connect this wire to the future soldering site for a short time, micro-soldering of copper and aluminum will be performed, which will subsequently allow soldering of wires using the usual method. To simplify the process, you can use soldering acid.

Soldering aluminum utensils (without a soldering iron)

Aluminum cookware is in definite demand among housewives, but sometimes it breaks down, and in order not to buy a new one (which costs a lot), you can repair such products by soldering without a soldering iron. The method below is suitable for sealing small holes (up to 7 mm in diameter).

1. It is necessary to clean the soldering area to a metallic shine using sandpaper or a file. If the dishes are enameled, then the enamel must be removed within a radius of 5 millimeters around the hole to be sealed. To do this, the enamel is removed from the dishes by lightly tapping with a hammer. Then the metal must be cleaned.
2. The soldering area is lubricated soldering acid or filled with crushed rosin. WITH inside A piece of tin is placed over the hole, and then the container is heated over the fire of the stove. If the dishes are enameled, then it is better to heat them over an alcohol lamp - this gives more targeted heating, and therefore the rest of the enamel will not crack from the high temperature.
3. When heated, the tin melts and tightly closes the hole in the dish. In this case, the help of a soldering iron is not required.

People learned to solder metal products back in ancient times, as soon as they learned to smelt tin and lead. Of course, the most in a simple way fastening metal products to each other is the use of an ordinary 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 in everyday life.

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.

Often in amateur radio practice, and just in everyday life, the question of soldering aluminum arises. Electrical wires, housings, leaky containers - you never know. But unfortunately, aluminum and its alloys really don’t like to be soldered. Even tinning this material (coating it with a layer of solder) is a problem, let alone soldering it properly. The only way out, as is commonly believed, is welding, and special welding, for example, argon-arc. However, aluminum can still be soldered, and efficiently, at home and without the use of special tools and technologies.

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

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

Fluxes for aluminum soldering

As mentioned above, the aluminum oxide film is extremely durable, and it is very difficult to destroy it using chemical methods. Nevertheless, there are many compositions that allow this very film not only to destroy, but also to prevent the appearance of a new oxide layer before the soldering process is completed. When choosing a particular flux, you should first of all focus on the type of soldering - soldering iron or torch. An incorrectly chosen composition will either not give the desired result if it is underheated, or it will simply burn in the flame of, for example, a gas burner.

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

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

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

High temperature flux for aluminum

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

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

Solders for aluminum

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

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

Solder for soldering aluminum Aluminum-13

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

The so-called fluxed ones, which already contain a special flux (usually in the form of a coating, but not necessarily), deserve special attention. There is an opinion that flux is not needed at all to work with them and, in principle, this is true. Nevertheless, it is very desirable for protecting the soldering area from oxidation during operation. Any passive flux that can withstand soldering temperatures is suitable for these purposes. The ideal solution here would be ordinary transformer oil, which electricians use when soldering high-voltage couplings.

Aluminum solder with flux coating

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

Selecting a Heat Source

There is not much choice here:

• regular soldering iron;
• open fire.

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

Soldering metal with a regular soldering iron

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

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

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

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

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

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

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

Application of a gas burner

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

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

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

In addition, you cannot take the gas burner in your hand, and therefore you will have to hold the soldered parts in your hands. If it's a massive object, you simply won't be able to hold it in the flame in constant motion to maintain the desired temperature while simultaneously trying to solder with your other hand. Well, since you will be heating from below, for normal soldering you will have to overheat the part (you need to solder from above), which means it can easily melt. Nevertheless, at the very least it is possible to solder aluminum over gas, but only at the very least.

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

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

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

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

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

How to solder silumin

First of all, let’s define that silumin is an alloy of aluminum with silicon and nothing else. For example, TsAM alloy (zinc, aluminum, magnesium) is a completely different material. If you are sure that you are holding a silumin part in your hands, then you can safely take up soldering - silumin can be soldered using the same technology as aluminum. Another thing is that silumin parts usually operate under a fairly high mechanical load. The material is already, to put it mildly, bad in this regard, but if you also solder it...

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