What is needed for soldering. How to solder wires with a soldering iron: copper, aluminum

The soldering process is chemical compound two metals with solder. Moreover, the crystal structure of the metal does not change. That is, the connected parts remain with their technical characteristics.

The connection itself is quite reliable, but much will depend on the type of solder and the soldering technology. In addition, it should be noted that not all metals can be joined by this process. The base metals, especially steel (iron), can be soldered together.

There are three technologies for soldering iron with tin:

soldering iron. For this you will have to use soft solders with a high content of lead;
blowtorch. Here you will need hard solders with a high content of tin;
electric soldering of iron.

The first method is used if the iron will not be subjected to heavy loads during operation. The second is the tinning of iron with tin, when tin solder is applied to the surface of a metal product and rubbed over its entire plane with a thin layer.

In this technology, a soldering flux is necessarily used. The third option is used on a production scale, for which special equipment is used.

Soldering sheet metal

Soldering of tin (thin sheet iron) is a common process in the manufacture of metal containers. But often at home it is necessary to fasten sheets of iron together, assembling hermetic structures. Therefore, before soldering one sheet to another, it is necessary to prepare everything you need.

For the process of soldering iron with tin, you will need solder with a small concentration of tin, for example, POS-40, flux, a soldering iron and an awl.

Flux in the process of soldering iron performs the functions of a solvent and an oxidizing agent at the same time. That is, wetting of the metal and protection from oxidative processes immediately occur. As fluxes, rosin and hydrochloric acid or zinc chloride are used and boric acid.

As for the soldering iron, for high-quality soldering with tin, it is better to choose an electric tool with a power of more than 40 watts. The old soldering tool, which is heated by the flame of a fire, is practically not used today even at home.

Sequencing

Here are the main steps in this process:

stripping connected sheets;
flux application;
soldering iron heating and tinning;
tin soldering;
cleaning the joint with gasoline.

Cleaning is carried out mechanically with sandpaper. If the contamination is large, then it will be necessary to carry out a solvent treatment. If it is not possible to clean it by this method, then etching with sulfuric acid is carried out.

Two pieces of sheet iron are brought to each other at a distance of 0.3 mm. Their edges are treated with a pasty flux with a brush. The soldering iron tip is cleaned with sandpaper, and the tool itself is included in electrical network through an outlet. To check if it has warmed up well, you need to place its sting in the ammonia mixture, which should boil.

Now the stage of tinning of iron is being carried out. That is, with the help of or its alloy, the edges of two sheets of tin are processed in order to cover them with a tin layer, which will perform protective functions against metal corrosion.

Everything is ready, it remains only to solder the two ends of the sheets. The tip of the soldering iron is brought to the joint along with solder from tin, and they both move smoothly along the joint boundary.

In this case, the sting must be pressed not with a sharp end, but with a flat edge, due to which the parts to be joined will also warm up at the same time, which will affect high quality soldered iron.

Features of working with galvanized products

Soldering galvanized with tin technological process no different from the previous one. But there are subtle nuances in the technology that affect the quality of the final result.

It is impossible to solder galvanizing with solders, which include a large amount of antimony. This substance, when in contact with a zinc coating, creates a fragile seam.

As a flux, it is better to use boric acid and zinc chloride. If the products themselves have already been tinned with tin during the production process, then rosin can be used as a flux.

When galvanized iron (sheet) and wire are connected, the latter must be bent at a right angle in order to increase the contact area of the two products.

The rest of the process is carried out in exactly the same way. By the way, it does not matter whether the wire was made of galvanized steel or ordinary steel.

There are several more important positions that must be taken into account in the process of soldering galvanized products. If soldering rods based on tin and lead are used for soldering iron, then it is better to add a flux based on zinc chloride and ammonium chloride for them. The ratio is 5:1 respectively.

Tin-cadmium solder requires caustic soda as a flux additive.

If galvanized iron products are interconnected, the protective layer of which includes more than 2% aluminum, then solder based on tin and zinc is used. And as a flux, hydrochloric acid and petroleum jelly (stearin) are used.

Regardless of which parts or assemblies are connected by soldering, after the end of the process and the seam has cooled down, rinse the junction with water to remove flux residues.

Safety

Soldering iron with tin is an unsafe process. Therefore, precautions must be strictly observed. Protective gloves are put on the hands, a stand must be installed under the soldering iron so that the heated tip does not touch the table and materials at hand. And the procedure itself must be carried out carefully.

With the seeming simplicity of the soldering operation, in fact, this is a serious procedure. And it must be treated with great care. Something was missed, even applied incorrectly, and we can assume that the quality of the joint has dropped sharply. Therefore, it is important to approach each stage responsibly, especially when it comes to cleaning two joined iron products.

Knowing how to properly solder is needed not only by radio amateurs and electrical installation specialists. To each home master you have to deal with the need for soldering when repairing household appliances.

Preparing the soldering iron for work

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 operation, is gradually covered with a layer of oxide and is subjected to mechanical damage. To obtain a good quality solder joint, the preparation of the soldering iron for work is carried out in the following sequence:

With a file with a fine notch, the working part of the sting is cleaned for a length of 1 cm from the edge. After stripping, the tool should acquire a reddish color, characteristic of copper, and a metallic sheen. During stripping, the sting is given a wedge-shaped, beveled, conical shape in order to solder what the master needs.
Plug in the soldering iron and heat it up to operating temperature.
The sting must be tinned, covered with a thin layer of tin - the same solder than soldering the connected conductors. To do this, the tip of the tool is immersed in rosin, and then a piece of solder is passed over it. Do not use a solder bar with rosin inside for tinning a soldering iron. To evenly distribute the solder, rub the working edges on the metal surface.

During operation, the floor will burn and wear out, so the soldering iron will have to be cleaned and tinned several times during the soldering process. You can clean the sting on a piece of sandpaper.

If the master will use a tool with a nickel-plated fireproof rod, it will have to be cleaned with a special sponge or damp cloth. Such a sting is tinned in a molten rosin, passing a piece of solder over it.

Soldering can be learned only in the process of work, but before that it is advisable to familiarize yourself with the basic operations.

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 semi-dry 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 a uniform layer of molten solder.

Before fluxing 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 place of soldering is heated with a soldering iron and covered with a thin layer of tin. Tinning in solid rosin is carried out as follows:

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

It is necessary to properly solder massive copper, bronze or steel parts using active fluxes that contain acids (F-34A, Glycerol-hydrazine, etc.). They will help create an even layer of semi-dry 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).

Heating and temperature selection

It is difficult for beginners to determine at what temperature the tool can be started. 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 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 tools have a thermostat, and it is easy to determine the degree of heating. But in the absence of a sensor, it should be borne in mind that a household soldering iron can be heated to a maximum of + 350 ... + 400 ° С. You can start working with the tool if the rosin and solder melt within 1-2 seconds. Most POS solders have a melting point of about +250°C.

Even an experienced craftsman will not be able to properly solder with a soldering iron that is not heated enough. With weak heating, the structure of the solder after solidification becomes spongy or granular. Soldering does not have sufficient strength and does not provide good contact details, and such work is considered a marriage.

Soldering

With sufficient heat, the molten solder should flow. 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's more convenient to use thin wire(bar) different section. Often, a layer of rosin is contained inside the wire, which helps to properly solder with a soldering iron without distracting from the process.

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

When working with radio components, it must be borne in mind that heating is dangerous for them. All operations are performed within 1-2 seconds.

When soldering connections of solid wires of large cross section, a thick rod can be used. With sufficient heating of the tool, it also melts quickly, but it can be distributed over the surfaces to be soldered more slowly, trying to fill all the grooves in the twist.

The art of soldering must be learned gradually. Starting from soldering wires and moving on to printed circuit boards - each of the methods has its own subtleties both in the selection of consumables for soldering and in technology. Today we will share with readers the basics of soldering and basic work skills.

What is the essence of soldering

Soldering uses the ability of some metals in the molten state to effectively spread over the surface of others under the influence of gravity and moderate surface tension. The solder connection is one-piece: the two parts to be joined are, as it were, enveloped in a layer of solder and remain motionless after it solidifies.

Since we will consider soldering in the context of soldering metals, the most important parameters will be mechanical strength and conductivity electrical connection. In most cases, these are directly proportional values, and if the two parts are tightly grasped, then the conductivity between them will also be high. However, the solder has a higher resistivity than even aluminum, so its layer should be as thin as possible, and hiding power should be as high as possible.

In order for soldering to be possible in principle, there are two conditions. The first and most important thing is the cleanliness of the parts at the soldering point. Solder attaches to the metal surface at the atomic level and the presence of even the slightest oxide film or contamination will make reliable adhesion impossible.

The second condition is that the melting temperature of the solder must be significantly lower than the temperature of the parts to be soldered. It seems obvious, but there are solders with a melting point higher than aluminum, for example. In addition, if the actual difference in melting temperatures is not high enough, when the solder solidifies, the temperature shrinkage of the parts may interfere with the normal formation of the solder crystal lattice.

Fluxes and solders - how to choose the right one

For the reasons described above right choice flux and solder is almost half the success in soldering. Fortunately, there are quite universal grades suitable for most tasks. The industry of application of almost all fluxes and solders is quite intelligibly indicated on the labels, but some aspects of their application still need to be known.

Let's start with fluxes. They are used for etching parts, removing and dissolving the oxide film with further protection of the metal from corrosion. As long as the surface is covered with flux, you can be sure that it is clean, as well as that the molten tin will wet it well and spread.

Fluxes are distinguished by the type of metals and alloys of the parts to be joined. Basically, these are mixtures of metal salts, acids and alkalis that actively react when heated with a soldering iron. Well, since there are quite a lot of oxide forms and contaminants, the cocktail should be specially selected for a specific type of metals and alloys.

Conventionally, fluxes for soldering are divided into two types. Active fluxes are created on the basis of inorganic acids, mainly perchloric and hydrochloric. Their disadvantage is the need to wash immediately after soldering, otherwise the acid residues cause quite a strong corrosion of the joint and in themselves have a sufficiently high conductivity that can cause a short circuit. But active fluxes can solder almost anything.

The second type of flux is created mainly on the basis of rosin, which can also be used in its pure form. Liquid flux is much more convenient to apply, it also contains alcohol and / or glycerin, which completely evaporate when heated. Rosin fluxes are the least effective when soldering steel, however, for non-ferrous metals and alloys, they or other compounds of organic chemistry are mainly used. Rosin also needs to be rinsed out as it tends to corrode in the long run and can become conductive by picking up moisture from the air.

Liquid and solid rosin

With solders, everything is somewhat easier. Basically, lead-tin solders of the POS brand are used for soldering. The number after the marking means the content of tin in the solder. The more it is, the higher mechanical strength and electrical conductivity of the joint, while lowering the melting point of the solder. Lead is used to normalize the solidification process; without it, tin can crack or become covered with needles.

There are special types of solders, primarily lead-free (BP) and other non-toxic ones, in which lead is replaced by indium or zinc. The melting temperature of BP is higher than that of conventional ones, but the connection is stronger and more resistant to corrosion. There are also low-melting solders that spread already at 90-110 ºС. These include Wood's and Rose's alloys, used for soldering components that are sensitive to overheating. Special solders are mainly used in the soldering of radio equipment.

Power and types of soldering irons

The main difference between a soldering tool is the type of its power source. For ordinary people, network soldering irons powered by 220 V are most familiar. They are used mainly for soldering wires and more massive parts, because it is almost impossible to overheat a copper wire, except, perhaps, for melting the insulation.

Plus network soldering irons in their high power. Due to it, high-quality and deep heating of the part is ensured, plus a bulky power supply is not required for operation. Among the shortcomings, one can single out the low convenience of work: the soldering iron is quite heavy, the tip is located far from the handle and such a tool is not suitable for fine work.

Soldering stations use thermal control to maintain a stable temperature level. Such soldering irons do not have significant power, usually 40 W is already the ceiling. However, for heat-sensitive electronics and soldering small parts, this tool is best suited.

Sting selection and care

Tips for soldering irons are distinguished by shape and material. With the form, everything is simple: the most primitive and at the same time universal is the styloid sting. Variations are possible in the form of a spatula, a cone with a blunt end, with a bevel and others. The main task when choosing a form is to achieve maximum area contact with a specific type of parts to be soldered, so that the heating is powerful and at the same time short.

According to the material, almost all the stings are copper, but they come with and without coating. Cover copper tips with chromium and nickel to increase heat resistance and eliminate oxidation of the copper surface. Coated tips are very durable, but they are somewhat worse wetted by solder and require careful handling. To clean them, use brass shavings and viscose sponges.

Uncoated stings can rightly be attributed to consumables for soldering. Such a sting during operation is periodically covered with a layer of oxides and the solder ceases to stick to it. The working edge needs to be cleaned and tinned again, so with intensive use, the sting wears off quickly enough. To slow down the burning of the sting, it is recommended to pre-forge it, and then grind it to give the desired shape.

Soldering wires

Soldering wires is the easiest. We dip the ends of the veins into the flux solution and draw a soldering iron over them, the tip of which is abundantly moistened in the flux. In the process of tinning, it is advisable to shake off excess molten solder. After applying the half-wires, they form a twist from the wires, and then carefully warm it up with a small amount of solder, filling the free space between the cores.

Another way is also possible, when, before twisting, the wires are simply thoroughly moistened with flux and soldered without prior tinning. This method is especially popular when soldering stranded wires and wires of small diameter. If the flux is of high quality, and the soldering iron provides a sufficiently strong heating, even a twist of 3-4 “fluffy” cores of 1.5 mm 2 will be well saturated with tin and will be reliably soldered.

Please note that in wiring, that is, inside junction boxes, soldering the wiring is not accepted. First of all, due to the non-detachable connection, plus everything, the spike has a significant transition resistance and there is always a high risk of its corrosion. Wires are soldered exclusively for connections inside electrical appliances or for tinning the ends of stranded wires before tightening them with screw terminals.

Working with electronic components

Soldering electronics is the most extensive and complex topic, requiring experience, skills and special equipment. However, an amateur can also replace a faulty element on a printed circuit board, even with only one network soldering iron.

Output elements (which are with legs) are the easiest to solder. They are preliminarily fixed (plasticine, wax) with pins in the holes of the board. Then, from the reverse side, the soldering iron is pressed tightly against the tail to warm it up, after which a wire of solder containing flux is introduced into the place of soldering. Too much tin is not needed, it is enough for it to flow into the hole from all sides and form a kind of elongated cap.

If the output element dangles and needs to be held by hand, then the place of soldering is first wetted with flux. It needs a very small amount, here it is optimal to use bottles of nail polish, pre-washed with acetone. With this soldering technique, tin is collected on a soldering iron in a small amount and a drop of it is carefully brought to the output of the element 1-2 mm from the board surface. The solder flows down the leg, evenly filling the hole, after which the soldering iron can be removed.

It is very important that the parts to be joined remain motionless until the solder has completely cooled. Even the slightest violation of the shape of tin during crystallization leads to the so-called cold soldering - crushing the entire mass of solder into many small crystals. characteristic feature such a phenomenon is a sharp clouding of the solder. It needs to be reheated and wait for uniform cooling in complete immobility.

Poor quality, cold soldering

To keep the tin in a liquid state, it is enough that the soldering iron is in contact with the tinned surface of the tip with any point of the wetted area. If the soldering iron literally sticks to the soldered parts, this indicates a lack of power for heating. For soldering heat-sensitive semiconductor elements and microcircuits, ordinary solder can be mixed with low-melting solder.

Soldering massive parts

Finally, let's talk briefly about the soldering of parts with high heat capacity, such as cable glands, tanks or dishes. The requirement for the immobility of the connection is most important here, large parts are pre-connected with clamps, small parts with lumps of plasticine, before soldering the connection, it is pinpointed in several places and the staples are removed.

Massive parts are soldered as usual - first at the junction, then filling the seam with liquid solder. However, solder for this purpose is used in a special, usually refractory and capable of maintaining high tightness, as well as good resistance to partial heating.

With this soldering, it is extremely important to keep the parts well warmed up. For these purposes, the soldering seam is heated directly in front of the place of soldering with a gas burner, and instead of a conventional electric soldering iron, a massive copper hatchet is used. It is also constantly heated in the flame of a burner, moistened with solder along the way, and then the joint is filled, partially melting the previous seam by several millimeters.

A similar soldering technique with heating can be used when working with an ordinary soldering iron, for example, when soldering thick cable cores. The sting in this case acts only as an operational tool for careful distribution of tin, and the gas burner serves as the main source of heating.

Soldering with a soldering iron- This is a physico-chemical technological operation for obtaining a permanent connection of metal parts by introducing a metal with a lower melting point into the gap between them.

Soldering with a soldering iron is much easier than it seems at first glance. The technology of soldering with a soldering iron was successfully used by the Egyptians 5 millennia ago and little has changed since then.

The requirements for the technological process of soldering and mounting of radio elements are set out in OST 107.460092.024-93 “Soldering of electrical connections of radio electronic equipment. General requirements to standard technological operations.

The process of soldering with a soldering iron begins with the preparation of the surfaces of the parts to be soldered. To do this, it is necessary to remove traces of dirt from the surfaces, if any, and oxide film. Depending on the thickness of the film and the shape of the surface, it is cleaned with a file or sandpaper. small areas and round wires you can clean the blade of a knife. The result should be a shiny surface without stains of oxides and shells. Fat contamination is removed by wiping with a cloth soaked in acetone or white spirit solvent (purified gasoline).

After preparing the surfaces, they must be covered with a layer of solder and tinned. To do this, flux is applied to the surface and a soldering iron tip with solder is applied.

For better heat transfer from the soldering iron tip to the part, you need to apply the tip so that the contact area is maximum. The cut of the tip of the soldering iron with solder should be parallel to the surface of the part.

The most important thing when soldering with a soldering iron is to heat the surfaces to be soldered to the temperature of the molten solder. With insufficient heating, the soldering will turn out to be matte with low mechanical strength. When overheated, the solder will not spread over the surface of the parts to be soldered and soldering will not work at all.

After completing the above preparation, the parts are applied to each other, and soldering is performed. electric soldering iron. The soldering time, depending on the thickness and weight of the parts, is from 1 to 10 seconds. Many electronic components allow a soldering time of no more than 2 seconds. As soon as the solder spreads evenly over the surfaces of the parts, the soldering iron is retracted to the side. The displacement of parts relative to each other until the solder is completely solidified is not permissible, otherwise the mechanical strength and tightness of the solder will be low. If this happens by accident, then you need to redo the soldering procedure.

Solder on the tip of a hot soldering iron, while waiting for soldering, is covered with oxides and residues of burnt flux. Before soldering, the tip must be cleaned. For cleaning, it is convenient to use a moistened piece of foam rubber of any density. It is enough to quickly draw a sting over the foam rubber and all the dirt will remain on it.

Before soldering, surfaces or wires that are connected by soldering must be tin-plated without fail. This is a guarantee of the quality of the solder joint and the enjoyment of work. If you do not have experience with a soldering iron, then before performing critical soldering work with a soldering iron, you first need to practice a little. It is easier to start with a single-core copper wire, which is how electrical wiring is made. The first step is to remove the insulation from the conductor.

How to tin copper wires

When the insulation is removed, you need to evaluate the condition of the conductor. As a rule, in new wires, copper conductors are not covered with oxides and can be tinned without stripping. It is enough to take a little solder on the tip of the soldering iron, touch it with rosin and move the tip along the surface of the conductor. If the surface of the conductor is clean, then the solder will spread over it in a thin layer.

If there is not enough solder, then an additional portion is taken with a touch of rosin. And so on, until the entire conductor is completely tinned. It is more convenient to tin wires by putting them on wooden platform, which I use as a stand for a soldering iron. Usually, in the place where I always puddle, rosin accumulates and the process goes faster, you can grab more solder without touching it, once again with a rosin sting.

Sometimes, contrary to expectations, although the conductor seems to be without oxides, it does not want to be tinned. Then I put it on an aspirin tablet and warm it up for a couple of seconds, and then I puddle on the site. Luditsya immediately without problems. Even a copper wire with obvious oxidation, without prior mechanical stripping, with aspirin immediately breaks with a thin layer of solder.

If you managed to tin the conductors with a soldering iron, as in the photo, then congratulations on your first successful soldering job.

It is difficult to get good soldering with a soldering iron the first time. There may be several reasons for this. The soldering iron is too hot for this type of solder, this can be determined by the rapidly forming dark film of oxides on the solder, which is located on the tip of the soldering iron. With excessive heating of the soldering iron tip, the working blade of the tip is covered with black oxide, and the solder is not retained on the tip. The temperature of the soldering iron tip is not sufficient. In this case, the soldering is loose and looks matte.

Only the use of a temperature controller can help here. Insufficient heating of the wire during tinning occurs with a small amount of solder on the working part of the tip. The contact area is small, and the heat is poorly transferred to the conductor. You need to practice until you can tin the wires as in the photo above.

After tinning the wire with a soldering iron, excess solder often remains on it in the form of sagging. In order to get a thin and even layer, you need to place the wire vertically, end down, the soldering iron vertically with the tip up, and draw the tip along the wire. The solder is heavy and all will go to the tip of the soldering iron. Just before this operation, you need to remove all the solder from the tip by hitting it lightly on the stand. In this way, you can remove excess from the place of rations and on printed circuit boards Oh.

The next stage of training is to solder a stranded copper wire with a soldering iron, the task is somewhat more difficult, especially if the wire is covered with oxide. It is difficult to remove the oxide film mechanically; you need to unwind the conductors and clean them individually. When I thermally removed the insulation from the wires, I found that the upper conductor was covered with oxide, and the lower conductor was unraveled. This is perhaps the most difficult case for tinning. But they are tinned with the same ease as single-core ones.

The first thing you need to do is put the conductor on an aspirin tablet and move it with a soldering iron so that all the conductors of the wire are wetted with the aspirin composition (when heated, aspirin melts).

Next, tin on the site with rosin, as described above, with the only difference being that you need to press the wire with the tip of the soldering iron to the site and, during the tinning process, rotate the wire in one direction so that the conductors intertwine into a single whole.

These are the copper wires after tinning.

From such an end of a tinned wire, it is possible to form a ring with the help of round-nose pliers, for example, for threaded connection to the contacts of a socket, switch or chandelier cartridge, or solder to a brass contact or a printed circuit board. Try to make such soldering with a soldering iron.

The main thing when connecting parts by soldering is not to move them relative to each other until the solder has hardened.

Soldering any parts with a soldering iron is not much different from soldering wires. If you managed to qualitatively tin and solder stranded wire, which means that you can perform any soldering.

How to tin a very thin enameled copper conductor

It is easy to tin with a soldering iron a thin conductor, with a diameter of less than 0.2 mm, insulated with enamel, if you use vinyl chloride. Insulating tubes and the insulation of many wires are made from this plastic. You need to put the wire on the insulation and lightly press it with the tip of the soldering iron, then drag the wire through, turning each time. From the heating of vinyl chloride, chlorine is released, which destroys the enamel and the wire is easily tinned.

This technology is indispensable when soldering with a soldering iron a wire of the licendrat type, which is a lot of thin wires coated with enamel and twisted into one conductor.

With the help of an aspirin tablet, it is also easy to tin an enameled thin wire with a soldering iron, in the same way the wire is pulled between the aspirin tablet and the soldering iron tip. There should be a sufficient amount of solder and rosin on the tip.

Soldering radio components with a soldering iron

When repairing electrical appliances, it is often necessary to solder radio elements from the printed circuit board and solder them back. Although this operation is not difficult, it still requires compliance with a certain soldering technology.

Soldering with a soldering iron resistors, diodes, capacitors

In order to solder two output radioelement from the printed circuit board, for example, a resistor or a diode, it is necessary to heat up the place of its soldering with a soldering iron until the solder melts and pull the radioelement output out of the board. Usually, the output of the resistor is removed from the printed circuit board by prying it over the output with tweezers, but the tweezers often slip off, especially if the output of the radio element on the solder side is bent.

For the convenience of work, the tweezer sponges need to be sharpened a little, the resulting grip will prevent the tweezers lips from slipping.

When dismantling radio elements, one more hand is always missing, you need to work with a soldering iron, tweezers and still hold the printed circuit board.

As a third hand, I use desktop tesks, with the help of which a section of the printed circuit board free from details can be clamped, and by placing a vise on any side face, orient the printed circuit board in three dimensions. Soldering with a soldering iron will be convenient.

After soldering the part from the board, the mounting holes are filled with solder. It is convenient to free the hole from the solder with a toothpick, a sharply sharpened match or a wooden stick.

The tip of the soldering iron melts the solder, the toothpick is inserted into the hole and rotates, the soldering iron is removed, after the solder has solidified, the toothpick is removed from the hole.

Before installing a new radio element for soldering, it is imperative to make sure that its conclusions are solderable, especially if the release date is not known. It is best to simply tin the leads with a soldering iron and then solder the element. Then the soldering will turn out to be reliable and the work will be a pleasure, not a torment.

How to solder SMD LEDs and other leadless components

Currently, leadless SMD components are widely used in the manufacture of electronic devices. SMD components do not have traditional copper wire leads. Such radio elements are connected to the tracks of the printed circuit board by soldering contact pads to them, located directly on the component case. Soldering such a component is not difficult, since it is possible to solder each contact individually with a low-power soldering iron (10-12 W).

But when repairing, it becomes necessary to desolder the SMD component to check or replace them, or desolder from an unnecessary printed circuit board for use as spare parts. In this case, in order not to overheat and break the component, it is necessary to simultaneously warm up all its outputs.

If you often have to solder SMD components, then it makes sense for the soldering iron to make a set of special tips, branching at the end into two or three small ones. With these tips, desoldering SMD components will be easy without damaging them, even if they are glued to the PCB.

But there are situations when there is no low-power soldering iron at hand, and in the existing powerful soldering iron, the tip has become attached and it is impossible to remove it. There is also a simple way out of this situation. You can wind a copper wire with a diameter of one millimeter around the soldering iron tip, as in the photo. Make a kind of nozzle and use it to successfully solder SMD components. The photo shows how I soldered SMD LEDs when repairing LED lamps. LED housings are very delicate and practically do not allow even small mechanical impacts.

If necessary, the nozzle can be easily removed and you can use the soldering iron on intended purpose. The width between the ends of the nozzle can be easily changed, thereby adjusting for soldering SMD components different sizes. The nozzle can be used instead of a low-power soldering iron, soldering small parts and soldering thin conductors to LED strips.

How to solder an LED strip with a soldering iron

Soldering technology LED strips not much different from soldering other parts. But due to the fact that the PCB substrate is a thin and flexible tape, soldering time should be kept to a minimum to avoid delamination of the printed tracks.

Repair of the iron car body by soldering

In the old days, when I drove a Soviet car, the technology of soldering iron with a soldering iron helped out when eliminating corrosion of the car body. If you just clean the place covered with rust and apply paintwork, then after a while the rust will appear again. Having covered the cleaned place with a soldering iron with a thin layer of solder, rust will never appear again.

I had to solder with a soldering iron and through corrosion holes in the sills and the zone of the wheel arches of the car body. To do this, you need to clean the surface around the hole with a strip of one centimeter and tin with solder with a soldering iron. From thick paper, cut out a pattern for a future patch. Next, along the pattern of brass 0.2-0.3 mm thick, cut out a patch and the area that will be soldered, tin with a soldering iron with a thick layer of solder. If necessary, the patch is attached desired shape. You can simply tap the patch by placing it on a thick, dense rubber. The edges outside file patches to nullify. It remains to attach a patch to the hole in the body and warm it well with a hundred-watt soldering iron along the seam. Puttying, priming, painting, and the body will be like new, while rusting in the repaired place will never happen again.

Most often for soldering printed circuit boards in radio products and household appliances they prefer to use ordinary pine resin rosin, but it can be replaced with other components. In molten form, it contributes to the spreading of tin solder along the copper tracks of the board. This allows you to securely solder the legs of the radio components and the ends of the connecting wires. Rosin allows you to effectively solder copper, tin and silver products. In order to solder galvanized, stainless iron, radiators, buckets, pans, various alloys, brass and other metals, acid solutions can be used.

Vial with acid solution for soldering metals

Acid solutions

It is important to choose the right acid solution. It depends on the type of metal from which the parts are made. It can be an aluminum or copper radiator, a kettle to be soldered, copper, brass or roofing iron:

Galvanized iron. Places where it is necessary to solder are treated with an acid solution, it is correctly called (zinc chlorate). Such a composition can be bought in specialized stores, the easiest way is to cook it yourself.

To do this, it is enough to throw pieces of zinc into 100 ml of hydrochloric acid, which can be removed from the case of finger batteries. After the end of the chemical reaction, zinc will dissolve, releasing a large amount of hydrogen.

It will be correct to carry out the process in a well-ventilated area, in the absence of an open flame.

After the solution has cooled and settled, the upper transparent yellow part is poured into a clean glass dish. The sediment is poured into the ground, into the sewer with metal pipes Not recommended. Acid can damage pipes and seals. The rest of the solution is ready for processing galvanized iron roofing.

How to solder sheets of roofing iron

Stainless steel. Before soldering, the surface is cleaned and treated with orthophosphoric acid, which includes the following elements:

up to 50% zinc chloride;
ammonia up to 0.5%;
dissolves in water with a pH concentration of 2.9%.

Orthophosphoric acid is used for soldering as a flux and for cleaning metal from rust.

The solution is transparent light yellow or colorless, when heated to 213ºС it is converted into H 4 P 2 O 7 (pyrophosphoric acid), which degreases the surface of metals. The composition dissolves the oxide film on various metals and alloys:

stainless steel;
brass;
nickel alloys;
copper alloys;
alloys of carbon metals and low alloy steel.

Application of acids

To solder hardware(pipes, radiator, buckets, pans), the surface of the elements is carefully cleaned, you can use a file or sandpaper. An acid solution is applied to the cleaned areas with a brush, after which the solder is melted on the surface with a soldering iron to a liquid state.

Liquid solder serves the cleaned places, when boiling, the acid flux comes to the surface. When the solder hardens, the elements to be soldered are securely and hermetically fixed.

You can solder with a powerful soldering iron or open fire from a gas burner. Can be used various sources heat depending on the area of the heated surface and the melting temperature of the solder.

The remains of the acid flux are washed off with water, preferably with a soapy, alkaline solution, this will prevent further corrosion of the metal.

Machined and brazed stainless steel elements

Acid can damage the skin and muscle tissue, while inhaling vapors affects the respiratory organs. In contact with air, hydrochloric acid enters into chemical reaction, smoke is visible above the open container. To work properly in these conditions wearing safety goggles, rubber gloves, gas mask, it is possible in a respirator.

If the solution comes into contact with the skin, wash this part of the body with a 6% alkaline solution or simple soap. It is not recommended to solder radio boards with acidic fluxes. Acidic components are difficult to wash off from them and contribute to the decay of copper tracks. It is better to replace them, there is a special paste for this.

It will be correct to store solutions with acid for soldering in containers made of the following materials:

glass;
ceramics;
porcelain;
fluoroplast.

Such dishes do not react with acid; in it, the prepared composition can be stored for a long time.

Soldering without a soldering iron

AT living conditions in the absence of a soldering iron, copper wires with a diameter of up to 2 mm can be soldered. For soldering radiators, dishes use special solder, blowtorches, gas-burners, since the copper rod of the soldering iron is not able to heat up large area surfaces. There are several ways:

Tinning and soldering wires in molten solder. The wire is preheated, applied to a piece of rosin, it melts and spreads evenly over the surface of the joint. The twisted wire is lowered into molten solder in a tin on a fire, you can heat it with a blowtorch. In order to solder the twist, it is advisable to hold it in boiling tin for up to 1 minute. The copper wires will warm up and the alloy will fill all the gaps between the twisted wires. In this way you can solder small parts copper, brass and other alloys.

Tinned and brazed copper wire

Soldering wires in the gutter. The stripped and twisted wires are placed in a piece of a 2-3 cm tube made of aluminum, 0.5-1 cm in diameter, sawn lengthwise. From above, it is covered with a mixture of small chips of solder and rosin dust; from below, this design is heated with a lighter, a candle or a small blowtorch.

Heating solder with a blowtorch (torch)

The mixture melts and carefully envelops all the junctions of the wires. After solidification, the aluminum gutter is removed, the junction is isolated.

Solder chips can be sharpened with a coarse-grained file.

Thin copper wire up to 0.75 mm can be laid on aluminum foil, pour a mixture of rosin and tin shavings, wrap tightly and heat for 3-4 minutes. The solder will evenly fill all the elements at the place of soldering; after cooling, the foil can be removed and discarded.

How solder paste is prepared

Soldering paste is sold in radio parts stores, but you can cook it yourself. In 32 ml of hydrochloric acid add 12 ml plain water, then pieces of zinc - 8.1 g. For this, enameled dishes are used.

After the end of the dissolution reaction, tin is added to the composition - 8.7 g. When the second dissolution reaction is over, the water is evaporated to a pasty consistency of the solution. The paste is transferred to a porcelain container, where the powder is poured, which includes:

lead - 7.4 g;
tin - 14.8 g;
dry ammonia - 7.5 g;
zinc - 29.6 g;
rosin - 9.4 g.

This paste is kneaded with 10 ml of glycerin, heated and mixed.

How to solder correctly, the sequence of actions:

the parts at the soldering site are cleaned, the wires are twisted;
the paste is applied with a brush, a thin layer;
the soldering surface is heated with a plasma lighter, burner, candle or alcohol tablet, even with matches or on a fire until the paste melts;
after melting, the soldering elements are removed from the heat source, the solder hardens.

The paste is very effective when it is necessary to solder copper wire, small parts made of alloys based on copper, brass, such as radiators, samovars and other products.

Soldering dishes

Buckets and pots with holes no more than 5-7 mm in diameter are recommended to be soldered without using a soldering iron with POS-60 solder. Holes on dishes can be safely soldered. To do this, the holes are carefully cleaned with sandpaper from the inside of the container. The hole along the edges is given a conical shape, the cleaned places are treated with a brush with a solution of soldering acid.

In order to prevent leakage of solder from the outside, the entire bottom or individual places where it is required to solder the holes, they are covered with thin tin plates. With inside powdered solder with rosin is poured into the cleaned holes. Places of soldering are heated over an open fire until the solder melts and fills all the cracks with it.

For radiators, stripping and soldering are carried out from the outside. To prevent the flow of solder inside, the hole is closed with a plate of tin, galvanized iron, which can be replaced with copper or brass. The choice depends on the material from which the radiator is made. Homogeneous metals and alloys that are similar in composition are easier to solder.

After the end of the process of soldering radiators, the inner and outer surfaces are thoroughly washed with an alkaline, soapy solution in order to exclude the effect of acidic components on the metal.

Flux bottle for aluminum soldering

When it is necessary to solder aluminum parts, special solders are used:

4:1 mixture of tin and zinc;
a mixture of 30:1 tin with bismuth;
powder 99:1 tin and aluminum.

The surface treatment sequence is the same as for the preparation of iron utensils. In order to qualitatively solder aluminum, rosin is added to the powder, but the melting point must be above 500ºС. It is recommended to stir the solder in the hole, you can use a thin copper tip of a soldering iron.

Paste for soldering printed circuit boards

The composition is not much different from the paste that is used to solder without a soldering iron, the following components are included in the powder:

tin - 14.8 g;
rosin - 4 g;
zinc dust - 738 g;
lead powder - 7.4 g.

For a pasty consistency, add diethyl ether - 10 ml, it can be replaced, use glycerin - 14 ml.

Soldering sequence:

the legs and tracks of the printed circuit board are cleaned;
in order to solder, the legs of the parts are inserted into the holes of the board;
places where it is necessary to solder on the board are lubricated with paste;
the paste is heated with a soldering iron until melting;
the solder spreads and solidifies, providing reliable electrical contact between the parts and the tracks of the printed circuit boards.

Soldering lessons. Video

You can learn how to solder correctly by watching this video.