Using solder with flux - what it is, where and how it is used

19 Feb 2012 | Section: Radio for home

Hello dear readers of the site sesaga.ru. Today I want to share with you the secret of good soldering, and tell you how to solder correctly with a soldering iron .

Every radio amateur has a minimum set of tools that he needs to assemble or repair any radio-electronic structure. These are all kinds of screwdrivers, pliers, wire cutters, files, hammers, etc. Therefore, I will not recommend anything here, but will focus on the most basic ones. In the future, if you need an additional tool, you will purchase it.

The first thing you need to purchase, if you don’t have one, is tweezers and a soldering kit:

1. Soldering iron

,
2. Solder (tin)
,
3. Flux (a jar of rosin)
.

Soldering iron

It’s better to buy a regular one with a power of 40W and a supply voltage of 220V. At home, you don’t need any other power; when you learn to solder, you’ll understand this. And when we assemble a power regulator for it that adjusts the temperature of the tip, it will become more convenient and versatile.

Solder.

solder is used to connect the surfaces of components and parts together.

- an alloy of lead and tin in various proportions.

As a rule, solder is made in the form of a wire or tube filled with flux. It is better to give preference to solder in the form of a wire, since flux will have to be used in any case.

Typically, solders differ in melting point and hardness, and are marked with alphabetic and numerical values, for example, POS-60.

POS - tin-lead solder, digital 60

means the percentage of tin in the alloy, respectively lead 40%. The more lead in the solder, the darker it is and the higher the melting point of the solder. For home use, it is better to purchase POS-60 solder with a melting point of about 190 °C, and also has good strength.

Silver percentage

The composition of all silver alloys used for soldering is regulated by GOST.

The markings always contain numbers next to the understandable abbreviation PSR. They indicate the percentage of silver.

In general, the following trend is observed: alloys with a high concentration of noble metal (50%, 72%) have low resistivity values. They are used to form compounds with high electrical conductivity.

Silver solders with a relatively low silver concentration (40-62%) are used for soldering parts that will not get very hot.

Characteristics of silver solders in tables:

Inexpensive metal alloys with a silver content of 10% to 45% are widely used in mechanical engineering. Metal composites with low silver concentrations produce a hard weld.

Almost all silver solders contain iron, lead, and bismuth in the alloy. The total amount of additives is just over 0.1%.

Many radio amateurs use tin-silver solder compositions containing only 2% expensive metal, 62% tin and 36% lead. The alloy easily passes from a liquid to a solid state and conducts electricity well.

In addition to domestic materials, suppliers offer a large number of imported silver solders. The price for them is naturally higher, but the quality is quite comparable to Russian products.

Fluxes.

Fluxes

designed to dissolve and remove oxides from the surface of soldered parts, serve to protect metal and solder surfaces from oxidation, and ensure good wetting of the surface of parts with liquid solder.

For example, sting

The soldering iron is made of copper, which oxidizes when heated, and a soot crust forms on the working surface of the tip. If you touch the solder with such a tip, it will naturally melt, but it will not remain on the working surface, but will simply roll off, so you will not be able to solder anything with such a soldering iron.

The most common and affordable flux is rosin

, which is made from pine resin. It looks like amber, transparent with a yellowish tint.

Flux Features

Flux protects the metal from interaction with oxygen and the subsequent formation of oxides on the joint surface. Its use improves the quality of the connection, with uniform distribution of solder. The danger of surface oxidation is eliminated, resulting in reliable adhesion of the atomic structure.

This material does not interact with the surfaces being joined, which eliminates the formation of an oxide film.

It has the following advantages:

• low heating temperature;
• small specific gravity;
• good spreading over the surfaces to be joined;
• resistance to evaporation;
• a variety of materials suitable for different soldering modes;
• ease of cleaning with solvent;
• anti-corrosion properties;
• compatibility with fatty and oxide films.

We prepare the soldering iron tip for soldering.

And so, you bought a soldering kit. The first step is to prepare the soldering iron, namely its working part ( tip

), since it is not yet very suitable for soldering. We clamp it with pliers, take a file, and begin to carefully process the tip, giving it the shape of a dihedral angle of approximately 30...45 degrees.

You have prepared the tip of the tip, but you cannot turn on the soldering iron yet, because when you turn it on for the first time, it emits smoke and an unpleasant odor, this is normal. This happens because during the first heating, the adhesive layer with which the mica sheets were glued together when winding the heating element burns out.

Types of nickel-plated soldering tips

• The needle-shaped tip is used to solder very small radio components, such as SMD. When repairing phones, such a tip is indispensable. It is used on boards with a high density of mounted parts.
• Tip-spatula - used for desoldering and in cases of installation of large radio components. They work with multi-pin microcircuits.
• The tip is in the shape of a drop - it is convenient for them to transfer solder with rosin to the place of soldering, which leads to improved quality of work.
• A tip with a curved shape - most often it is used to solder radio components that are in a copper shell, so that no excess solder remains on the board. It can also be used for regular soldering. The soldering iron heats up to a temperature of 290-300 C.

When working with a soldering iron, you must always keep it perfectly clean. New soldering tips are usually hammered to create fine nicks on the surface. Subsequently, they are carefully trimmed with a file to give the tip the most correct shape.

Then the tip should be tinned using solder with rosin. That is, cover with a thin layer of solder, dipping it in rosin.

The design of the heating element of a soldering iron.

Let's look at the sectional design of the heating element.

The heating element in soldering irons is usually a nichrome wire wound around a metal tube into which a copper rod (tip) is inserted. The electric current heats up the nichrome wire, which in turn transfers heat to the copper rod, heating it.

To isolate this wire from contact with the protective casing and metal tube, mica is used, which is laid in layers between them.

Pros and cons of rosin

This material is considered an excellent dielectric. When using it, finished solder joints do not lose their properties, and the soldering properties remain high . Rosin has a high level of resistance to moisture.

Rosin is especially often used by home craftsmen. This became possible thanks to the positive properties of the material. For example:

• ease and accessibility of use;
• low cost;
• low melting temperature. Thanks to this, it can be used at low soldering temperatures;
• moisture resistance;
• long shelf life;
• has the ability to destroy oxide films that form on the melting surface;
• harmlessness.

When working with rosin, you must also take into account the disadvantages inherent in the material. Among them are the following:

• low level of activity, which requires its use during soldering more than 1 time;
• hygroscopicity (it is possible that moisture can be absorbed from the vapor after soldering, contributing to the development of the corrosion process);
• used for soldering connections of low complexity;
• its fragility complicates its storage and transportation.

There are several types of rosin, each of which is intended for soldering certain materials: gum, extraction, tallow.

Homemade soldering iron stand.

Another thing you need, and you can’t live without it, is a soldering iron stand

.
You can buy it there in the store, or you can make it yourself. It is enough to take a small wooden block and a metal lid used in home canning. You will put the remaining solder and flux in it, and also tin the leads of the parts and the soldering iron tip in it. Read also: How to connect an electric bell to your home
It is advisable to make a rectangular bath from the lid. Just be careful when you cut the lid, its edges are sharp as a blade, do all work with gloves.

So. Cut a rectangle out of the lid with scissors, make markings with a marker, as in the picture, and bend the edges with pliers. When finished, be sure to file the edges of the bath and nail it to the block with two small nails. All. Your stand is ready.

Advice!

Take electrical tape and tape the soldering iron wire to the handle as shown in the photo. This will save you from any surprises. Believe me.

Now you can turn on the soldering iron. If you are indoors, then open the window, plug in the soldering iron and expose it to fresh air for 30-40 minutes. After this time, the product is ready for use.

Technology for creating at home

Preparing solder for soldering silver with your own hands allows you to save significant amounts, but requires melting and foundry equipment and certain skills.

You can do it in the following sequence:

• chop scrap with metal scissors;
• grind the filler material;
• remove iron dust from them with a powerful magnet;
• use precise scales to weigh out 20 gram portions of the charge;
• add 10% borax and mix thoroughly;
• put the weighed portion into a melting spoon and heat with a burner until completely melted;
• warm up the casting mold, called “ingus”;
• pour a spoonful of melt into the ingus in one go;
• cool the mold under running water;
• knock the finished solder out of the mold.

During work, you should be careful, use personal protective equipment, a hood, and do not leave the burner unattended.

Final preparation of the soldering iron tip. Service.

As you noticed, the copper has turned dark blue, so we take a file and go over the working part of the tip, removing scale from it. Now quickly dip the tip into a jar of rosin and touch the solder to both sides.

Then, using small movements along the bottom of the bath, as if you were working with an eraser, move the tip back and forth, periodically dipping it in rosin for better wetting, until the working part is covered with solder on both sides. Happened! The sting should always be this white

.

Remember! The key to good soldering is a soldering iron tip that is free of oxides and well tinned. The solder should be a thin layer evenly distributed over the entire working surface of the tip

.

Here you go. You have prepared the soldering iron for soldering, and now you can safely start practicing. In the second part of the article, how to properly solder with a soldering iron with rosin, you will learn how to tin and solder conductors together

. Good luck!

Knowledge of how to solder correctly is needed not only by radio amateurs and electrical installation specialists. Every home handyman has to deal with the need for soldering when repairing electrical appliances.

Physico-chemical properties and composition

The chemical composition of the soldering material is determined by GOST and affects its physical and chemical parameters. To change the properties, elements such as copper, zinc, tin, antimony and others are included in the composition.

Standard for dobvako content in various brands of solders.

To reduce the cost of the composition when soldering less critical compounds, silver is diluted with tin, lead, and zinc, which are cheap relative to silver.

Preparing the soldering iron for use

Before soldering with a soldering iron, you should properly prepare it for work. In everyday life, an electric soldering iron with a copper tip is most often used, which, during storage and use, gradually becomes covered with a layer of oxide and is subject to mechanical damage. To obtain a solder joint of good quality, the soldering iron is prepared for use in the following sequence:

1. Using a finely cut file, clean the working part of the tip to a length of 1 cm from the edge. After cleaning, the tool should acquire a reddish color, characteristic of copper, and a metallic luster. During stripping, the tip is given a wedge-shaped, beveled, cone-shaped shape in order to solder what the master needs.
2. Plug in the soldering iron and heat it to operating temperature.
3. The tip must be tinned and covered with a thin layer of tin - the same solder used to solder the connected conductors. To do this, the tip of the tool is immersed in rosin, and then a piece of solder is passed along it. You should not use a solder rod with rosin inside for tinning a soldering iron. To distribute the solder evenly, rub the working edges against a metal surface.

During operation, the half-plate will burn and wear off, so the soldering iron will have to be cleaned and tinned several times during the soldering process. You can clean the tip with a piece of sandpaper.

If the master uses a tool with a nickel-plated, non-burnable rod, it will have to be cleaned with a special sponge or damp cloth. They tin such a sting in molten rosin, running a piece of solder over it.

Soldering can only be learned on the job, but before that it is advisable to become familiar with the basic operations.

How to choose the right solder?

Correctly selected solder will help you organize a communication system of any complexity without much effort. If we are talking about working at home, it is worth using a material that melts at low temperatures.

The use of high-temperature hard-melting elements in everyday life is problematic, since it requires heating the working alloy to 600-900 degrees. Achieving this without special equipment is quite difficult.

Soldering of edible copper can be carried out using special solders that do not contain toxic, noxious and aggressive elements that can harm health

The use of metals and their derivatives that melt at high temperatures involves some risk. During processing, they can damage or even burn through thin-walled copper pipes.

To prevent this from happening, it makes sense to take strong but low-melting soft solder, and leave the hard option for thick-walled copper communications.

When large loads are not expected on the system, it is not at all necessary to use refractory solder, unless otherwise required. In basic household systems, soft light-alloy solders are sufficient to create a reliable connection.

To connect copper pipes in gas networks, you should choose silver-containing solders. They provide maximum seam strength, vibration neutrality and high resistance to external and internal influences.

You will have to pay a little more for silver, but the safety, reliability and durability of the system will pay off all financial costs over time.

Fluxing or tinning

The traditional and most affordable flux is rosin. If desired, you can solder with a solid substance or its alcohol solution (SKF, Rosin-gel, etc.), as well as TAGS flux.

The legs of radio components or chips are covered with half-milk at the factory. But to get rid of oxides, you can tin them again before installation, lubricating them with liquid flux and covering them with an even layer of molten solder.

Before processing with flux or tinning, copper wire is cleaned with fine emery cloth. This removes the oxide layer or enamel insulation. Liquid flux is applied with a brush, and then the soldering area is heated with a soldering iron and covered with a thin layer of tin. Tinning in solid rosin is done as follows:

• melt a piece of the substance on a stand and heat the conductor in it;
• feed the solder rod and distribute the molten metal evenly over the wire.

Correctly soldering massive copper, bronze or steel parts should be done using active fluxes that contain acids (F-34A, Glycerin-hydrazine, etc.). They will help create an even layer of poluda and firmly connect parts of large objects. Tin is applied to large surfaces with a soldering iron, spreading solder evenly over them. After working with active flux, acid residues should be neutralized with an alkaline solution (for example, soda).

Read also: How to tighten a belt with two rings

Solder with flux

Solders with built-in flux represent their own separate type. It is also called tubular. It looks like an empty rod with a protective chemical built into it.

When melted, the rod melts and the flux is used for protective functions. Some of the frequently used models are Brazetec Comet 3476U and Castolin 192 FBK.

This type of flux is practical to use since you perform soldering and protection at the same time. The time you would have spent selecting flux and coating the solder with it is freed up.

But these types do not always protect as well as possible. If you are looking for quality, it would be better to choose these materials separately. We will tell you later why flux is needed.

Preheating and temperature selection

It is difficult for beginners to determine at what temperature the tool can start working. The degree of heating should be selected depending on the type of material:

• soldering microcircuits requires heating no higher than +250°C, otherwise the parts may be damaged;
• large individual radio components can withstand heating up to +300°C;
• Tinning and joining of copper wire can occur at +400°C or slightly lower;
• massive parts can be heated at the maximum power of the soldering iron (about +400°C).

Many models of instruments have a thermostat, and it is easy to determine the degree of heating. But in the absence of a sensor, it is worth keeping in mind that a household soldering iron can be heated to a maximum of +350... +400°C. You can start working with the tool if the rosin and solder melt within 1-2 seconds. Most POS grade solders have a melting point of about +250°C.

Even an experienced craftsman will not be able to solder correctly with a soldering iron that is not heated enough. With low heat, the solder structure becomes spongy or granular after solidification. Soldering does not have sufficient strength and does not ensure good contact between the parts, and such work is considered a defect.

What is solder?

Solder is a pure metal or thermoplastic alloy made from several components. Designed to connect copper parts into a common integrated network.

When exposed to high temperatures, the solder melts, spreads across the processing area and seals the surface. After final cooling, a strong, even seam without errors is formed on the pipe material

The technology of joining two fragments, carried out according to this principle, is called soldering.

Among the main advantages of the technique it is worth highlighting:

• connection without deformation;
• preservation of the original shape of the processed parts;
• absence of any internal tension;
• excellent strength and high level of tightness of the created seam;
• resistance of the bonded area to different temperature conditions, including intense heating;
• simple separation of seam sections in case of need to change the system format.

Soldering is carried out with special equipment - a soldering iron, a gas torch or a blowtorch. Immediately before work, the area is thoroughly cleaned of surface defects and technical oils, and only then work begins.

The process of connecting pipe fragments is easy and quick, but requires mandatory compliance with basic safety rules. To avoid problems and injuries, you should wear thick work gloves on your hands, cover your face and eyes with special goggles or a mask, and protect your clothes with a thick apron. This will protect the technician from potential accidents.

For soldering at home, a soldering iron is most often used. A torch or lamp is used where the power capabilities of a soldering iron are not enough or where it is necessary to connect parts of great thickness and impressive mass.

Working with solder

When heated sufficiently, the molten solder should become flowable. For small jobs, you can take a drop of alloy on the tip of the tool and transfer it to the parts to be joined. But it is more convenient to use thin wire (rod) of different sections. Often inside the wire there is a layer of rosin, which helps to solder correctly with a soldering iron without distraction from the process.

With this method, a hot tool heats the surface of the connected conductors or parts. The end of the solder rod is brought to the tip and pushed a little (1-3 mm) under it. The metal instantly melts, after which the remainder of the rod is removed, and the solder is heated with a soldering iron until it acquires a bright shine.

When working with radio components, you need to take into account that heating is dangerous for them. All operations are performed within 1-2 seconds.

When soldering connections of single-core wires of large cross-section, you can use a thick rod. When the tool is heated sufficiently, it also melts quickly, but you can distribute it over the surfaces to be soldered more slowly, trying to fill all the grooves of the twist.

Any novice specialist involved in the maintenance and repair of radio electronics is faced with the need to buy a device designed for high-quality work on connecting damaged sections of the microcircuit. Let's try to figure out how to solder correctly with a soldering iron with rosin, what a novice specialist and a master with a wealth of knowledge needs to know.

Technical characteristics of produced solders

Basic principles and rules for soldering work

In order to understand and find out how to properly use a soldering iron for soldering wires, you need to have a minimum set of tools:

• Soldering iron, preferably electric from the main power source of 220 volts.
• Tin or other interchangeable solders.
• Rosin.

The power of the soldering iron should be no more than 40 watts, the standard power supply is 220 volts. For domestic use, this power of the device is quite enough. Ready-made solder is needed for high-quality connection of parts and assemblies. As the main components of solder we use tin with lead components, as well as traditional rosin. The retail network sells ready-made tubes with a compound inside or special wire. The latter option is recognized as the most effective and best in many performance parameters.

What fluxes are suitable?

To create a strong connection, it is necessary to properly prepare the surfaces for soldering. To do this, they are cleaned mechanically. Silver solder is used with soldering flux - a liquid or paste that destroys the oxide film and facilitates soldering, increasing the fluidity of the melt.
Borax powder is widely used. It is diluted in a small amount of water, heated and stirred until solder paste is formed.

With this composition you can solder from 490 to 910°C

Ready-made soldering fluids and pastes are also widely available on the market. It is better for a novice master to use purchased materials. Making your own fluxes requires skills in handling strong chemicals.

Characteristics of solder and rosin

Next, we’ll figure out how to properly solder wires with a soldering iron with rosin and tin when choosing the required brand of solder. In this case, the PIC marking, the so-called tin-lead solder, is suitable. The marking contains digital values, so 60 is the percentage of tin, and 40% is the lead content. You can find solders on the market that have a high lead content. This material has the best characteristics that ensure high quality work when connecting parts. The composition differs in color, the melting temperature will be an order of magnitude higher than with conventional series and PIC markings, but the quality of the processing site will also be high.

Rosin plays an important role in this process, which allows you to solve not only the problem of how to properly solder wires with a soldering iron, but also helps to achieve the necessary strength of the connection. The main purpose of rosin is to remove oxides from processed soldered parts. The use of rosin is mandatory, since the copper tip, when heated, forms a specific carbon deposit that interferes with the quality of ensuring the strength of the connection of parts on the microcircuit.

Read also: What can be made from a Ural saw

By its nature, rosin is a natural material that contains resin components from coniferous wood, usually pine. The substance has a specific pine smell. There are several varieties of rosin on sale, it is a liquid mass or in a solid state. In addition, in order to know how to properly learn to solder with a soldering iron, a beginner can use a combined version of rosin with the addition of ethyl alcohol, the so-called alcohol-rosin composition.

Rules for soldering with rosin

Now we will move on to the practical part of the problem, how to properly solder wires with a soldering iron with rosin and tin, the process itself. First of all, you need to prepare a minimum set of tools. Before working on how to work with a soldering iron for wires, you need to flatten the tip and clean it properly. If the tip is not flattened, we recommend doing it yourself without damaging the main body of the device. Remember, the thinner the tip, the more effective the result. As a rule, the best and optimal sting option would be a tip at an angle of 30-45 degrees.

Basic rules for soldering with a soldering iron:

• All work must be carried out in a ventilated area, open the windows.
• We plug in the soldering iron, wait until it warms up and the characteristic smell goes away. It is necessary for the sting to be heated.
• Turn off the soldering iron for a while and clean the tip of old dirt.
• We turn on the device again.
• We lightly tin the parts and parts of the parts to be connected. To do this, we wait until the tip warms up to the desired temperature, lightly touch the rosin and direct the tip to the place where the joint is processed.
• To take the required amount of solder, again point the hot tip at the rosin. We apply it to a pine board and repeat the operations again with the remaining parts.
• A beginner needs to experiment at his leisure to understand how to properly solder copper wires with a soldering iron.
• A typical beginner’s mistake is to carry out all connection work with a bare tip, where there is no solder or flux. This fatal mistake can cause the entire chip board to catch fire.
• Next, what is needed for soldering wires with a soldering iron for copper materials. For this technological process, it is enough to have one tinning. First, we warm up the tip, touch the rosin, and then apply the tip to the working surface of the workpiece. After this, we lift the wire again, lower it into rosin, again apply a hot tip and connect the contacts again.
• During the soldering process, the rosin itself will begin to smoke (a natural process). This means that the wire is surrounded by the necessary mass of rosin intended for the job.
• In the process of soldering and completing the task of what kind of soldering iron is needed for soldering wires, pay attention that if the color of the wire changed from yellow to silver, then the whole process was quite successful.
• Now all that remains is to solder the remaining 2 wires, but you need to tin the ends.

What you need to know to ensure soldering safety measures

Like any technological process of working with power tools, it requires safety measures. what power a soldering iron is needed for soldering wires , it is no more than 40 watts, but for beginners it would be best to use a low-power tool; a device up to 20 watts is quite enough. Rosin, like solder, has a negative effect on the mucous membrane of the eyes and respiratory tract. It is imperative to consider ways to ventilate the room. Use a soldering iron that has a grounding system, this way you will ensure complete electrical safety of the work.

Now let's try to figure out what can be soldered with a soldering iron? Yes, almost everything related to metal, and not necessarily radio electronics. Damaged metal buckets and dishes can look attractive again if we get the soldering iron and the required solder group to work effectively. When working, use readily available materials, such as a wooden block, as well as ordinary plumbing tools - pliers, wire cutters, hammers. You just need to try the experiment once on a simple metal object, and then you will have a great desire to eliminate defects on household items made of metal at home. When carrying out any work with a soldering iron, comply with the minimum fire and electrical safety requirements. Use special protection and be sure to ventilate the room where you plan to carry out technological work on joining parts using rosin and solder.

Classification of solders for copper pipes

Solders for high-quality and reliable soldering of copper pipes are made from different components. Products differ from each other in shape and chemical composition.

The type and parameters of the connecting elements are determined by the area of ​​subsequent operation of the pipe system made of copper parts.

Melting point differences

Based on the level of temperature treatment, solders are divided into three types:

• low temperature;
• medium temperature;
• high temperature.

Low temperature options melt in the range from 150 to 450 °C. They do not change the original physical parameters of the parts. In the connection area, a neat but not too strong seam is created. Intended for use in heating and water supply networks that are not subject to heavy loads.

Ensure the tightness and integrity of pipes with a diameter of up to 10 cm installed in communication systems transporting coolant with temperatures up to 130 °C.

Medium and high temperature materials soften at temperatures ranging from 450 to 1100/1850 °C. They guarantee the most durable, strong connection, not sensitive to external influences.

High-temperature solders are characterized by good reliability and are suitable for use in centralized and private heating systems and gas pipelines. Allows you to make an additional outlet without resorting to dismantling the entire complex

The area connected by medium-temperature or high-temperature solder exhibits resistance to mechanical damage and calmly tolerates active thermal loads.

Separation by chemical composition

According to the chemical composition, modern, practical solders are divided into soft, fusible and hard, refractory.

The first category includes the following items:

• lead - contain only pure lead and melt at temperatures from 180 to 230 °C;
• tin - consist of tin and melt at 220 °C, creating a durable and ductile seam;
• lead-tin - can contain from 15 to 90% tin. The melting temperature of such elements is 183-280 °C;
• tin-copper - 97% consist of high-quality tin and 3% copper. They are among the most popular and are sold at a reasonable price. Form a strong connection with good corrosion resistance;
• copper and silver - 95% copper and 5% silver. They are characterized by high strength characteristics and provide reliable adhesion between fragments.

Soft, low-melting components are used to combine pipes with a diameter of 6 to 108 mm into a single complex. In the joint area, a neat seam with a width of 7 to 50 mm is formed.

Soft low-temperature solders are relevant for organizing heating networks, individual and centralized water mains. This option is absolutely not suitable for gas communications.

Lead is considered an element harmful to human health. The use of lead-containing solders is strictly prohibited in networks supplying water to apartment or private buildings, enterprises or public institutions. This prohibition does not apply to other types of communications.

Hard, refractory materials are suitable for high-temperature processing:

• copper in combination with silver and zinc - contains 30% copper, 44% silver and 26% zinc. The adhesion area has good strength, retains ductility, effectively resists corrosion and demonstrates increased thermal conductivity;
• copper with phosphorus - an alloy of 94% copper and 6% phosphorus. The soldering process does not require the use of flux. Makes a strong and reliable connection, but partially loses its elasticity at low ambient temperatures;
• silver – during soldering requires the mandatory use of flux. Creates a strong, reliable seam with good ductility and high corrosion resistance. It is much more expensive than analogues made of simple metals and is not widely used. It is used where there is economic feasibility and increased demands are placed on the quality of the pipe connection.

Using refractory solders, complexes of pipes with a diameter of 12 to 159 mm are installed, including gas communication networks, heating lines and water mains with a diameter of 28 mm.

To prevent copper from losing its strength characteristics during the soldering process, you should not immerse the part with a fresh seam in water or subject it to artificial blowing for cooling. A reliable, strong and durable connection will be provided by metal that has cooled naturally

The use of classic copper-phosphorus or any other elements is allowed when creating overlap joints. This coupling option ensures maximum structural strength and increases the operating life of the pipeline.

Soft solders are usually made in the form of coils for ease of use. Solid elements are supplied in the form of wires of different lengths.

To enhance the integrity and increase the strength characteristics of the seam, the overlap should be at least 5 mm. During processing, you need to leave a microscopic gap so that the solder is drawn in evenly, fills the voids and forms a reliable sealed patch

Features of rosin

Rosin is a substance consisting of resin acids and their isomers. It is obtained from the resin of coniferous trees, therefore it has a characteristic resinous odor and has an ocher, yellow, orange or red tint. The scope of application of this chemical compound is wide: light industry (production of eco-leather, plastic, rubber, paint and varnish products, etc.); food industry (additive E915); art (rubbing parts of bowed musical instruments); sports (prevention of slipping in ballet, baseball, weightlifting); electrical engineering and electronics (soldering).

soldering rosin

Rosin is optimal for soldering because:

• Provides a quick tinning process;
• guarantees the strength of the contact point;
• if necessary, it can be easily removed from surfaces;
• not exposed to moisture;
• does not enter into a chemical reaction with the surfaces to be joined;
• non-toxic.

Typically, soldering uses solid rosin, which is sold in the form of glassy bars or powder. However, some technicians prefer liquid rosin. It contains organic compounds, which make it convenient to apply the substance to small surfaces. The brush included in the bottle allows you to use this liquid precisely. Residues can be removed with alcohol or water.

It is necessary to use rosin in order to get rid of oxide films covering any metal surfaces. The abietic acid contained in rosin ensures instant dissolution of such deposits, while ensuring good spreading of the metal.

A few words about fluxes

The purpose of fluxes is to protect the soldering metal from the effects of oxides by isolating the soldering area from air. The most common composition of fluxes for repairs is a mixture of potash and borax in equal proportions; sometimes soda is used instead of potash.

To obtain powdered borax, you must first dry the aqueous solution of borax. It is better to do this on a regular gas stove in a porcelain evaporation container.

Once the solution turns into crystals, they need to be ground to a powder. Flux must be removed after soldering with a weak heated acid solution.

Soldering with a soldering iron

In order to start soldering, you need to prepare a workplace and the necessary tools. Regardless of the type of proposed work, the following requirements are imposed on the workplace:

• The presence of good lighting will allow you not only to work comfortably, but also to notice small flaws in the soldered parts, which is difficult if there is a lack of light;
• No flammable items;
• Free working space on which you can easily place the part to be soldered;
• The presence of ventilation will make work not only more comfortable, but also safer; inhaling molten rosin has a negative effect on the respiratory system;
• A magnifying glass makes it possible to work even with small parts and thin wires;
• A simple stand solves the problem of placing a heated soldering iron.

The next stage of preparation will be the choice of tool, and a beginner is always faced with the question of what is needed for soldering with a soldering iron.

Soldering iron selection

The basis of high-quality soldering is heating metal parts to the soldering temperature; accordingly, for each type of work it is recommended to use soldering irons of different capacities:

• For soldering radio components and microcircuits, it is best to use a soldering iron with a power of no more than 60 Watts, otherwise you can overheat the part or simply melt it;
• Parts up to 1 mm thick will warm up better when using a tool with a power of 80-100 Watts;
• Parts with a wall thickness of up to 2 mm require greater power and some experience in operation, so soldering of such parts will not be considered in this article.