How to solder a board at home. How to tin copper wires
It would seem that the question itself, how to solder correctly with a soldering iron, is very simple. I dipped the tip in rosin, put solder on the tip, and touched the contacts of the part that needed to be soldered.
In fact, doing this job requires certain skills that come with experience. Otherwise, how can we explain the difference in the quality of soldering made by different craftsmen?
How to quickly learn to solder
In order to master the basics of soldering, you need to choose the right tool. Let's start with the main thing, with the choice of a soldering iron.
Choosing the right soldering iron
In most cases, a soldering iron with a 40-60 W copper tip, a stand, flux (rosin is best) and solder will do.
You should not chase expensive ceramic devices and soldering stations. Suitable for training basic set. And don't forget tweezers.
IMPORTANT! Once you have mastered the basics of soldering, it will become clear that the training set is suitable for 90% of homework with a soldering iron.
Many advanced radio amateurs have been using Soviet soldering irons without regulators for decades.
And the quality of soldering can be the envy of the owner of a soldering station equipped with the latest technology.
To solder correctly, you need to practice
If the tool is new, it is necessary to prepare the tip, sharpen and tin it. This method is only suitable for copper tips.
How to tin a sting, step-by-step instructions
If you have already used the tool, this video will help you properly prepare the tip for use.
Next, cut a few pieces of wire different sections, and find any broken electrical appliance (transistor radio or cassette recorder). This set makes an excellent training ground.
How to tin the tip correctly if the solder does not stick - video
Unsolder and put back the radio components on the circuit, connect the wires with and without twisting. The best learning tool is independent practice on components that you don’t mind spoiling.
Sequencing
Do not rush to immediately connect two parts with solder. First, learn how to strip the wire and pad on the circuit board. Then practice tinning the stripped wire.
Try removing a two- and then three-contact radio component (for example, a transistor) from the board. And only after that try to solder completely. Remember the main rule - first warm up the soldering area, then add solder to it.
There are several ways to add solder.
- Apply the molten composition to the tip of the sting
- Bring the solder wire to the joint and, pressing everything with a tip, wait until the composition begins to melt.
Flux is used to ensure that areas of parts or conductors prepared for soldering do not oxidize during soldering. To solder circuit boards, you must use fluxes that do not contain acid. The simplest and most common flux is rosin. It is better to buy natural pine rosin. Much best result You can get it if you stock up on liquid flux. To prepare it, grind rosin into powder and add it to ethyl or boric alcohol. This rosin is applied to the soldered areas with a brush. Having purchased new soldering iron, the sting must be cleaned and tinned - coated thin layer solder. When you first turn on a new soldering iron to the network, the connecting components of the insulation usually burn out - an unpleasant smelling smoke comes out of the soldering iron, so it is better to turn on the soldering iron for the first time in the open air. Now clean the soldering iron tip with a file, then heat the soldering iron again. Dip the tip into the rosin and then touch it to a piece of solder. In the layer of molten solder, move the tip along wooden stand so that its entire surface is covered with a layer of solder.
When soldering small radio components, it is convenient to have a very thin soldering iron tip, literally a couple of millimeters in diameter. It is not convenient to solder boards with an overheated soldering iron. Moreover, there is a danger of overheating the soldered radio components. It is advisable to equip a soldering iron
Soldering skills modern life, saturated with electrical appliances and electronics, is as necessary as the ability to use a screwdriver and a plunger. There are many methods for soldering metals, but first of all you need to know how to solder with a soldering iron, although other methods are feasible and may also be needed at home. This article is intended to help those who want to master the technology of manual soldering work.
Fluxes
Soldering fluxes are divided into neutral (inactive, acid-free), which do not react chemically with the base metal or interact to an insignificant extent, activated, which chemically act on the base metal when heated, and active (acidic), which act on it even when cold. In regard to fluxes, our century has brought the most innovations; mostly still good, but let's start with the unpleasant ones.
First, technically pure acetone for washing rations is no longer widely available due to the fact that it is used in the underground production of drugs and itself has a narcotic effect. Substitutes for technical acetone are solvents 646 and 647.
Secondly, zinc chloride in activated flux pastes is often replaced with sodium teraborate - borax. Hydrochloric acid is a highly toxic, chemically aggressive volatile substance; Zinc chloride is also toxic, and when heated it sublimates, i.e. evaporates without melting. Borax is safe, but when heated it releases a large number of water of crystallization, which slightly worsens the quality of soldering.
Note: borax itself is a soldering flux for soldering by immersion in molten solder, see below.
Good news - now on sale the widest range fluxes for all cases of soldering life. For ordinary soldering work, you will need (see figure) inexpensive SCF (alcohol rosin, former CE, second in the list of acid-free fluxes in Table I.10 in the figure above) and soldering (etched) acid, this is the first acid flux on the list. SKF is suitable for soldering copper and its alloys, and soldering acid is suitable for steel.
SKF rations must be washed: rosin contains succinic acid, which destroys metal upon prolonged contact. In addition, accidentally spilled SCF instantly spreads throughout large area and turns into an extremely sticky muck that dries for a very long time, the stains from which cannot be removed from clothes, furniture, or the floor or walls. In general, SKF is a good flux for soldering, but not for slow-witted people.
A complete substitute for SCF, but not so nasty if handled carelessly, is TAGS flux. Steel parts are more massive than is permissible for soldering with soldering acid, and more durable, they are soldered with F38 flux. The universal flux can be used to solder almost any metal in any combination, incl. aluminum, but the strength of the joint with it is not standardized. We'll come back to soldering aluminum later.
Note: Radio amateurs, keep in mind - there are now fluxes on sale for soldering enameled wires without stripping!
Other types of soldering
Hobbyists also often solder with a dry soldering iron with a bronze untinned tip, the so-called. soldering pencil, pos. 1 in Fig. It is good where solder spreading outside the soldering zone is unacceptable: in jewelry, stained glass, soldered objects of applied art. Sometimes surface-mounted microchips are also dry soldered with pin spacing of 1.25 or 0.625 mm, but this is a risky business for experienced specialists: poor thermal contact requires excessive soldering iron power and prolonged heating, and it is impossible to ensure stable heating during manual soldering. For dry soldering, use harpius from POSK-40, 45 or 50 and flux pastes that do not require removal of residues.
Dead-end twists of thick wires (see above) are soldered by immersion in a futorka - a bath of molten solder. Once upon a time, a futor was heated with a blowtorch (pos. 2a), but now this is primitive savagery: an electrofutor, or soldering bath (pos. 2) is cheaper, safer and gives best quality rations. The twist is introduced into the futor through a layer of boiling flux supplied to the solder after it has been melted and heated to operating temperature. The simplest flux in this case is rosin powder, but it soon boils away and burns even faster. It is better to flux the futor with brown, and if the soldering bath is used for galvanizing small parts, then this is the only possible variant. In this case Maximum temperature futorki should be at least 500 degrees Celsius, because zinc melts at 440.
Finally, solid copper in products, e.g. pipes are soldered using high-temperature flame soldering. It always contains unburnt particles that greedily absorb oxygen, so the flame has, as chemists say, restorative properties: removes residual oxide and prevents new ones from forming. At pos. 3 you can see how the flame of a special soldering torch literally blows out everything unnecessary from the soldering area.
High-temperature soldering is carried out, see Fig. on the right, evenly rubbing the soldering area with pressure 1 with a stick of hard solder 2. The flame of the torch 3 should follow the solder so that the hot spot is not exposed to air. First, the soldering zone is heated until the colors become tarnished. You can solder something else to the surface tinned with hard solder using soft solder as usual. For more information on flame soldering, see later when it comes to pipes.
It’s funny, but in some sources the soldering torch is called a soldering station. Well, a rewrite is a rewrite, whatever you get from it. In fact, a desktop soldering station (see next figure) is equipment for fine soldering work: with microchips, etc., where overheating, spreading of solder where it is not needed, and other flaws are unacceptable. The soldering station accurately maintains the set temperature in the soldering zone, and, if the station is gas, it controls the gas supply there. In this case, the burner is included in its kit, but on its own soldering torch the soldering station is nothing more than a quarry - St. Basil's Cathedral.
How to solder aluminum
Thanks to modern fluxes, soldering aluminum has become generally no more difficult than copper. F-61A flux is intended for low-temperature soldering, see fig. Solder – any analogue of Avia solders; There are different ones on sale. The only thing is that it is better to insert a tinned bronze rod into the soldering iron with notches on the tip approximately like a file. Under the layer of flux, it will easily scrape off the strong oxide film, which prevents aluminum from being soldered just like that.
F-34A flux is intended for high-temperature soldering of aluminum with 34A solder. However, you need to be very careful when heating the soldering zone with a flame: the melting point of aluminum itself is only 660 Celsius. Therefore, it is better to use flameless chamber soldering (furnace-heated soldering) for high-temperature aluminum soldering, but the equipment for it is expensive.
There is also a “pioneer” method of soldering aluminum with preliminary copper plating. It is suitable when only electrical contact is required and mechanical stress in the soldering area are excluded, for example, if it is necessary to connect an aluminum casing to the common busbar of a printed circuit board. “In a pioneering way,” aluminum soldering is carried out on the installation shown in Fig. left. Powder copper sulfate pour in a heap into the soldering zone. A harder toothbrush, wrapped in bare copper wire, is dipped into distilled water and the vitriol is rubbed with pressure. When a copper spot appears on the aluminum, it is tinned and soldered as usual.
Fine soldering
In soldering printed circuit boards has its own characteristics. How to solder parts onto printed circuit boards, in general, see the small master class in the drawings. Tinning of wires is no longer necessary, because the terminals of the radio components and chips are already tinned.
In amateur conditions, firstly, there is little point in tinning all current-carrying paths if the device operates at frequencies up to 40-50 MHz. IN industrial production boards are tinned using low-temperature methods, for example. spraying or galvanic. Heating the tracks along their entire length with a soldering iron will worsen their adhesion to the base and increase the likelihood of delamination. After installing the component, it is better to varnish the board. This will immediately darken the copper, but this will not affect the performance of the device in any way, unless we are talking about microwaves.
Then, look at the ugly thing on the left of the trail. rice. For such a marriage, and in the bad memory of the Soviet MEP (Ministry of Electronic Industry), installers were demoted to loaders or helpers. It's not even about appearance or excessive consumption of expensive solder, and, firstly, the fact that during the cooling of these plaques both the mounting pads and the parts overheated. And large heavy influxes of solder are rather inert weights for already weakened tracks. Radio amateurs are well aware of the effect: if you accidentally push a “cuttlefish” board onto the floor, 1-2 or more tracks peel off. Without waiting for the first re-soldering.
Solder beads on printed circuit boards must be round and smooth with a height of no more than 0.7 times the diameter of the mounting pad, see on the right in Fig. The tips of the leads should protrude slightly from the beads. By the way, the board is completely homemade. There is a way to do it at home printed circuit installation as accurate and clear as the factory one, and even display the inscriptions you want. White spots are reflections from the varnish during photography.
Swellings that are concave and especially wrinkled are also a defect. Just a concave bead means that there is not enough solder, and a wrinkled bead means that air has penetrated into the solder. If the assembled device does not work and there is a suspicion of a faulty connection, look first in these places.
ICs and chips
In essence, an integrated circuit (IC) and a chip are the same thing, but for clarity, as is generally accepted in technology, we will leave the “microchip” microcircuits in DIP packages, up to and including large ones in terms of the degree of integration, with pins separated by 2.5 mm, installed in mounting holes or soldering pins if the board is multilayer. Let the chips be ultra-large “million-dollar” ICs, mounted on the surface, with pin pitches of 1.25 mm or less, and the microchips – miniature ICs in the same cases for phones, tablets, and laptops. We do not touch processors and other “stones” with rigid multi-row pins: they are not soldered, but installed in special sockets, which are sealed into the board once when it is assembled at the enterprise.
Soldering iron grounding
Modern CMOS (CMOS) ICs are the same in sensitivity to static electricity as TTL and TTLSh, holding a potential of 150 V for 100 ms without damage. Amplitude value effective voltage networks 220 V – 310 V (220x1.414). Hence the conclusion: you need a low-voltage soldering iron, for a voltage of 12-42V, connected through a step-down transformer on the hardware, not through a pulse generator or capacitive ballast! Then even a direct test on the tip will not ruin expensive chips.
There are still random, and even more dangerous, surges in mains voltage: welding was turned on nearby, there was a power surge, the wiring sparked, etc. Most reliable way to protect yourself from them - do not remove “stray” potentials from the soldering iron tip, and do not let them escape from there. For this purpose, even at special enterprises of the USSR, the circuit for switching on soldering irons was used, shown in the figure:
The connection point C1 C2 and the transformer core are connected directly to the circuit protective grounding, and to the middle point of the secondary winding - the screen winding (an open coil of copper foil) and the grounding conductors of the workplaces. This point is connected to the circuit with a separate wire. If the transformer has sufficient power, you can connect as many soldering irons as you like to it, without worrying about grounding each one individually. At home, points a and b are connected to a common ground terminal with separate wires.
Microcircuits, soldering
Microcircuits in DIP packages are soldered like other electronic components. Soldering iron – up to 25 W. Solder – POS-61; flux - TAGS or alcohol rosin. You need to wash off its remains with acetone or its substitutes: alcohol takes the rosin hard, and it is not possible to completely wash it off between the legs either with a brush or a rag.
As for chips, and especially microchips, soldering them manually is strongly not recommended for specialists of any level: this is a lottery with very problematic winnings and very likely losses. If it comes to such subtleties as repairing phones and tablets, you will have to fork out for a soldering station. Using it is not much more difficult than a hand soldering iron, see the video below, and the prices of quite decent soldering stations are now affordable.
Video: microcircuit soldering lessons
Microcircuits, desoldering
“Correctly”, ICs are not desoldered for testing during repairs. They are diagnosed on site using special testers and methods, and the unusable ones are removed once and for all. But amateurs cannot always afford it, so just in case, below we provide a video about methods for desoldering ICs in DIP packages. Craftsmen also manage to desolder chips with microchips, for example, by slipping a nichrome wire under a number of pins and heating them with dry soldering irons, but this is an even less winning lottery than manual installation of large and extra-large ICs.
Video: desoldering microcircuits - 3 methods
How to solder pipes
Copper pipes are soldered using a high-temperature method with any hard copper solder with activated flux paste, which does not require removal of residues. Next, there are 3 options:
- In copper (brass, bronze) couplings - soldering fittings.
- With full distribution.
- With incomplete distribution and compression.
Soldering copper pipes in fittings it is more reliable than others, but requires significant additional costs for couplings. The only case when it is irreplaceable is a drainage device; then a tee fitting is used. Both soldered surfaces are not tinned in advance, but are coated with flux. Then the pipe is inserted into the fitting, securely fixed and the joint is soldered. Soldering is considered complete when the solder stops going into the gap between the pipe and the coupling (0.5-1 mm is needed) and protrudes outward as a small bead. The fastener is removed no earlier than 3-5 minutes after the solder has hardened, when the joint can already be held by hand, otherwise the solder will not gain strength and the joint will eventually leak.
How pipes with full distribution are soldered is shown on the left in Fig. The “distributed” soldering holds the same pressure as the fitting one, but requires additional pressure. special tools for unrolling the socket and increased solder consumption. Fixing the soldered pipe is not necessary; it can be pushed into the socket with a twist until it jams tightly, so soldering with full distribution is often done in places that are inconvenient for installing the clamp.
In home wiring made from thin-walled pipes of small diameter, where the pressure is already low and its losses are insignificant, soldering with incomplete expansion of one pipe and narrowing of the other may be advisable, pos. I on the right in Fig. To prepare the pipes, a round stick made of hard wood with a conical point of 10-12 degrees on one side and a truncated-conical hole of 15-20 degrees on the other, pos. II, is sufficient. The ends of the pipes are processed until they fit into each other without jamming for approx. by 10-12 mm. The surfaces are tinned in advance, more flux is applied to the tinned ones and they are connected until they jam. Then they heat until the solder melts and prop up the narrowed pipe until it jams. Solder consumption is minimal.
The most important condition for the reliability of such a joint is that the narrowing must be oriented along the flow of water, pos. III. Bernoulli's school law is a generalization for an ideal fluid in a wide pipe, and for a real fluid in a narrow pipe, due to its (liquid) viscosity, the maximum pressure jump shifts opposite to the current, pos. IV. A component of pressure force arises, pressing the narrowed pipe against the distributor, and the soldering turns out to be very reliable.
What else?
Oh yes, soldering iron stands. The classic one, on the left in the figure, is suitable for any rod. Where the trays for solder and rosin should be placed on it is up to you; there are no regulations. For low-power soldering irons with an apron, simplified stands-brackets in the center are suitable.
Any radio amateur or House master, who is interested in radio design, electrical appliance repair and other activities related to electrical and electronic devices, must be able to solder. You can read about how to solder with a soldering iron with rosin in many manuals. But it is very important to have not only theoretical knowledge, but also practical skills and work experience. Let's consider the basic requirements and stages of training soldering work. What every radio amateur needs to know?
For a beginner radio amateur, it is very important to know the basics of working with a soldering iron.
Amateur radio soldering kit
Every fan of working with radio-electronic devices should have a minimum set of tools. This includes pliers, screwdrivers, files, wire cutters and much, much more. But the most important elements soldering kit are: the soldering iron itself (their variety is quite large, everyone should choose a convenient model to suit their preferences), solder (a metal alloy based on different combination lead and tin) and flux (the most common of them is rosin - a product of processing pine resin). It is also worth adding tweezers here, which can greatly facilitate the soldering of small elements. Let's take a closer look at the parts of this set.
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Soldering iron features
For a beginner radio amateur, a soldering iron with a power of 40 W is suitable.
If you are a novice craftsman, then it is best to purchase a regular soldering iron for a 220 V network with a power of 40 W. This is the basis from which it is better not to deviate in order to avoid a lot of problems. In the future, as your skill grows, you can purchase a power regulator for your soldering iron, which will help you independently regulate the temperature of your soldering iron tip and, accordingly, carry out more delicate work. When soldering, the cleanliness of the tip surface is extremely important, since a film of oxides constantly forms on it, preventing good contact with the solder. To do this, you need to warm up the soldering iron and clean its tip with sandpaper. After this, dip the soldering iron in rosin so that a dark, damp film forms on the surface of the tip. Then you can dip the tip of the tip into the solder and rub it there so that the solder covers the work surface in an even layer. Later, when a new film of oxides is formed, the operation can be repeated.
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Solder is an alloy of tin and lead.
Using solder, metal structural elements are connected to each other.
Solder is a mandatory part of soldering in radio electronics. It is he who helps connect various metal structural elements together. From a chemical point of view, it is an alloy of lead and tin, the proportions can vary significantly depending on the manufacturer and the job being performed. Most often, solder is sold in the form of a silver-metallic wire, but there are options in the form of a hollow tube, the inside of which is pre-filled with rosin (flux) for ease of soldering. But still experienced craftsmen they prefer to choose wire solder, since flux will still be needed for each soldering, only its quantity differs. Each type of solder has its own alphanumeric marking, which indicates to buyers its performance characteristics and composition.
For example, there are varieties of solders such as POS 40 or POS 60. The abbreviation stands for tin-lead solder, and the number indicates the percentage of the main element of the alloy - tin. Many craftsmen prefer to work with pure tin or alloys with the highest possible content. The higher the lead level, the higher the melting point and the darker the color. The same POS 60 has a melting point of 190 degrees Celsius.
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Flux Features
The main task of fluxes is to clean metal oxides from the surface of the elements being joined. In addition, such compositions prevent the appearance of these oxides in the future. Flux also helps improve contact between parts by wetting and preparing the surface for contact with solder. You can see for yourself the effectiveness of the flux on specific example. Try soldering with a soldering iron with and without rosin. The fact is that the main metal of the tip is copper, which very quickly during the heating process becomes covered with a film of oxides that prevents contact with the solder; it will simply roll off the surface of the soldering iron in hot drops. But as soon as you dip the tip into the rosin, a wet-looking film of flux will form on the surface of the soldering iron, which will hold the solder on the soldering iron tip and allow you to carry out soldering work. When speaking of flux, most craftsmen mean pine rosin. It is she who most often plays this role, outwardly resembling frozen pieces of amber. The same rosin is used to treat the bows of musical instruments.
But pine resin is not the only flux option. In addition, to work with metal utensils, zinc dissolved in hydrochloric acid is used; this mixture is called soldering acid. But this composition is not applicable in radio engineering due to its causticity. One drop is enough to destroy an important connection or metal wire. Acids cannot be used in soldering radio components; the best flux is rosin. But sometimes craftsmen use alcohol solutions of rosin when it is necessary to treat contacts in hard to reach place. To do this, ground rosin is dissolved in alcohol and then applied in a thin layer to the site of the future connection.
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A few secrets of soldering
In principle, there are no particular difficulties in soldering various metal elements together. You can solder, especially without going into any nuances of craftsmanship, but if you want to do the job efficiently, it’s worth considering a few small secrets.
If you have never dealt with a soldering iron before, we recommend that you practice a little. To do this, you can take several pieces copper wire in the shell. With it you can develop skills in proper tinning and soldering.
In addition to those nuances that are listed when describing the main components of soldering (soldering iron, flux and solder), you need to take into account others:
- When soldering, the cleanliness of the surfaces being connected is extremely important. All contact points must be thoroughly cleaned and prepared for soldering. To do this, you must first clean the future soldering area with a knife or sandpaper. As you clean, you will see the metal become lighter and brighter. This involves removing the thin and unnoticeable film of copper oxides that covers the surface of your wire. After physically cleaning the contacts, you need to dip the tip of a heated soldering iron into rosin and transfer a little rosin onto the surface to be treated. Carefully and carefully disperse the molten flux over the workpiece. As a result, your working surface should be cleaned of oxides and covered with a film of rosin.
- It is extremely important to correctly connect the conductors together, as well as warm up the place of future connection. To do this, you need to evenly and tightly press the ends of the soldered conductors, which were previously tinned, as described above, to each other, and then apply a soldering iron tip with a drop of molten solder on it to the junction. Hold for a while, let the conductors warm up enough so that the solder alloy spreads and fills the entire space between the elements being fused. The heating should be such that the solder spreads over work surface, and did not freeze in one lump. Remove the soldering iron and let the solder cool. Do not move the conductors under any circumstances. It is better if they cool down for at least 10 seconds. Now the solder securely holds both conductors together.
- If the surface to be soldered is large and there is not enough solder to fill it all, then simply wait until the first batch of solder has cooled and apply another one with a soldering iron. Achieve even distribution of the alloy over the surface being treated. Solder that has frozen in a lump is an indicator of poor-quality work by a beginner. With a real master, solder covers the surface, like a second skin, evenly and on all sides.
One of the most reliable methods of connecting wires and parts is soldering. How to solder correctly with a soldering iron, how to prepare a soldering iron for use, how to get a reliable connection - more on all this below.
In everyday life, “ordinary” electric soldering irons are used. There are those that operate from 220 V, there are from 380 V, there are from 12 V. The latter are characterized by low power. They are used mainly in enterprises in areas with increased danger. They can also be used for domestic purposes, but they heat up slowly, and the power is not enough...
You need to choose the one that fits comfortably in your hand
Power selection
The power of the soldering iron is selected depending on the nature of the work:
IN household It is enough to have two soldering irons - one low-power - 40-60 W, and one “medium” - about 100 W. With their help, it will be possible to cover about 85-95% of needs. But it is still better to entrust the soldering of thick-walled parts to a professional - this requires specific experience.
Preparing for work
When the soldering iron is plugged in for the first time, it often starts to smoke. This burns out the lubricants that were used in the production process. When the smoke stops coming out, turn off the soldering iron and wait until it cools down. Next you need to sharpen the tip.
Sharpening the tip
Next, you need to prepare the tip for work. It is a cylindrical rod made of copper alloy. It is fixed using a clamping screw, which is located at the very end of the heat chamber. In more expensive models, the tip may be slightly sharpened, but basically there is no sharpening.
We will change the very tip of the sting. You can use a hammer (flatten the copper as you need), a file or emery (just grind off the unnecessary). The shape of the tip is chosen depending on the intended type of work. It can be:
- Flatten it into a spatula (like a screwdriver) or make it flat on one side (angled sharpening). This type of sharpening is needed if massive parts will be soldered. This sharpening increases the contact surface and improves heat transfer.
- You can grind the edge of the tip into a sharp cone (pyramid) if you plan to work with small parts (thin wires, electrical parts). This makes it easier to control the degree of heating.
- The same cone, but not so sharp, is suitable for working with conductors of larger diameter.
Sharpening with a “spatula” is considered more universal. If it is formed with a hammer, the copper will be compacted and the tip will need to be adjusted less often. The width of the “shovel” can be made larger or smaller by trimming it on the sides with a file or emery. With this type of sharpening you can work with thin and medium-sized parts to be soldered (rotate the tip to the desired position).
Soldering iron tinning
If the soldering iron tip does not have a protective coating, it must be tinned - covered with a thin layer of tin. This will protect it from corrosion and rapid wear. This is done the first time you turn on the instrument, when the smoke has ceased to be emitted.
The first method of tinning a soldering iron tip:
- bring to operating temperature;
- touch the rosin;
- melt the solder and rub it along the entire tip (you can use a wooden sliver).
Second way. Moisten a rag with a solution of zinc chloride and rub the heated tip on the rag. Melt the solder and rub it with a piece of table rock salt over the entire surface of the tip. In any case, the copper should be covered with a thin layer of tin.
Soldering technology
Almost everyone uses it now electric soldering irons. Those whose work involves soldering prefer to have a soldering station, “hobbyists” prefer to make do with ordinary soldering irons without regulators. Have several soldering irons different power Sufficient for various types of work.
To figure out how to solder correctly with a soldering iron, you need to have a good understanding of the process in general, then delve into the nuances. So let's start with brief description sequences of actions.
Soldering involves a sequence of repeated actions. We will talk about soldering wires or radio parts. These are the ones you encounter more often on the farm. The actions are:
This completes the soldering. It is necessary to cool the solder and check the quality of the connection. If everything is done correctly, the soldering area will have a bright shine. If the solder appears dull and porous, this is a sign of insufficient temperature during soldering. The soldering itself is called “cold” and does not provide the required electrical contact. It is easily destroyed - just pull the wires in different directions or even pick it up with something. The soldering area may also be charred - this is a sign of a reverse error - too high temperature. In the case of wires, this is often accompanied by melting of the insulation. However, electrical parameters are normal. But, if the conductors are soldered when installing the wiring, it is better to redo it.
Preparation for soldering
First, let's talk about how to properly solder wires with a soldering iron. First you need to remove the insulation. The length of the exposed area can be different - if you are going to solder wiring - power wires, expose 10-15 cm. If you need to solder low-current conductors (the same headphones, for example), the length of the exposed area is small - 7-10 mm.
After removing the insulation, the wires must be inspected. If there is varnish or oxide film on them, it must be removed. Freshly stripped wires usually do not have an oxide film, and sometimes varnish is present (copper is not red in color, but brownish). Oxide film and varnish can be removed in several ways:
- Mechanically. Use fine grit sandpaper. It is used to process the exposed part of the wire. This can be done with single-core wires of fairly large diameter. Process sandpaper thin wiring is inconvenient. Stranded ones can generally be cut off.
- Chemical method. Oxides are highly soluble in alcohol and solvents. Lakovoe protective covering can be removed with acetylsalicylic acid (regular pharmacy aspirin). The wire is placed on the tablet and heated with a soldering iron. Acid will corrode the varnish.
In the case of varnished (enameled) wires, you can do without stripping - you need to use a special flux, which is called “Flux for soldering enamel wires”. It itself destroys the protective coating during soldering. Just so that it does not subsequently begin to destroy the conductors, it must be removed after soldering is completed (with a damp cloth or sponge).
If you need to solder a wire to some metal surface(for example, a ground wire to a loop), the preparation process does not change much. The area to which the wire will be soldered must be cleaned to bare metal. First, all contaminants (including paint, rust, etc.) are mechanically removed, after which the surface is degreased using alcohol or a solvent. Next you can solder.
Fluxing or tinning
When soldering, the main thing is to ensure good contact between the parts being soldered. To do this, before starting soldering, the parts to be joined must be tinned or treated with flux. These two processes are interchangeable. Their main purpose is to improve the quality of the connection and facilitate the process itself.
Tinning
To process the wires you will need a well-heated soldering iron, a piece of rosin, and a small amount of solder.
We take the stripped wire, lay it on rosin, and heat it with a soldering iron. While warming up, we turn the conductor. When the wire is completely covered in molten rosin, put a little solder on the soldering iron tip (just touch it with the tip). Then we remove the wire from the rosin and run the tip of the tip along the exposed conductor.
Wire tinning - mandatory stage when soldering
In this case, the solder covers the metal with a thin film. If it is copper, it turns from yellow to silver. The wire also needs to be turned a little, and the tip must be moved up/down. If the conductor is well prepared, it becomes completely silver, without gaps or yellow paths.
Flux treatment
Here everything is both simpler and more complicated. Easier in the sense that you only need the composition and a brush. Dip the brush into the flux and apply a thin layer of the compound to the soldering area. All. This is simplicity.
Difficulty in choosing flux. There are many varieties of this composition and you need to select your own for each type of work. Since we are now talking about how to properly solder wires or electronic components (boards) with a soldering iron, we will give several examples of good fluxes for this type of work:
For soldering electronic components (printed circuit boards), do not use active (acid) fluxes. Better - water or alcohol based. Acidic ones have good electrical conductivity, which can disrupt the operation of the device. They are also very chemically active and can cause destruction of insulation and corrosion of metals. Due to their activity, they prepare metals very well for soldering, so they are used if it is necessary to solder a wire to metal (the pad itself is processed). The most common representative is “Soldering Acid”.
Preheating and temperature selection
If you want to know how to solder correctly with a soldering iron, you need to learn how to determine whether the soldering area is hot enough. If you use a regular soldering iron, you can navigate by the behavior of rosin or flux. At a sufficient level of heating, they actively boil, release steam, but do not burn. If you lift the tip, drops of boiling rosin remain on the tip of the tip.
When using a soldering station, proceed from the following rules:
That is, at the station we set it 60-120°C higher than the melting temperature of the solder. As you can see, the temperature gap is large. How to choose? Depends on the thermal conductivity of the metals being soldered. The better it removes heat, the higher the temperature should be.
Soldering
When the soldering area is hot enough, you can add solder. It is introduced in two ways - molten, in the form of a drop on the soldering iron tip, or in solid form (solder wire) directly into the soldering zone. The first method is used if the soldering area is small, the second - for large areas.
If you need to add a small amount of solder, touch it with the soldering iron tip. There is enough solder if the tip turns white and not yellow. If a drop hangs, this is too much, it must be removed. You can tap the edge of the stand a couple of times. Then they immediately return to the soldering zone, running the tip along the soldering area.
In the second case, we insert the solder wire directly into the soldering zone. When heated, it begins to melt, spreading and filling the voids between the wires, taking the place of evaporating flux or rosin. In this case, you need to remove the solder in time - its excess also does not have a very good effect on the quality of soldering. In the case of soldering wires this is not so critical, but when soldering electronic elements on boards is very important.
In order for the soldering to be of high quality, everything must be done carefully: strip the wires, warm up the soldering area. But overheating is also undesirable, as is too much solder. This is where you need measure and experience, and you can gain it by repeating all the steps a certain number of times.
Device for more convenient soldering - third hand
How to learn to solder with a soldering iron
To begin, take several pieces of single-core wire of small diameter (you can use installation wires, those used in communications, etc.) - they are easier to work with. Cut them into small pieces and practice on them. Try to solder the two wires together first. By the way, after tinning or fluxing, it is better to twist them together. This will increase the contact area and make it easier to hold the wires in place.
When soldering is reliable several times, you can increase the number of wires. They will also need to be twisted, but you will have to use pliers (two wires can be twisted by hand).
Normal soldering means:
After you have mastered soldering several wires (three...five), you can try stranded wires. The difficulty lies in stripping and tinning. You can only clear it chemical method, and tin, having previously twisted the wires. Then you can try to twist the tinned conductors, but this is quite difficult. You will have to hold them with tweezers.
When this is mastered, you can train on wires of a larger cross-section - 1.5 mm or 2.5 mm. These are the wires that are used when laying wiring in an apartment or house. Here you can train on them. Everyone too, but working with them is more difficult.
After soldering is completed
If the wires were treated with acid fluxes, after the solder has cooled, its remains must be washed off. To do this, use a damp cloth or sponge. They are soaked in the solution detergent or soap, then remove moisture and dry.
You know how to solder correctly with a soldering iron, now you need to acquire practical skills.