An electric soldering iron is available in every household. home handyman. No repairs can be done without it. electrical devices, nor when connecting various small metal parts. But sometimes the soldering iron can fail. If this happens, then you shouldn’t always rush to buy a new one. Of course, not always, but you can repair a soldering iron yourself, without resorting to the services of specialists for a fairly substantial fee. As a rule, repairing an electric household soldering iron consists of replacing the heating element, which serves to heat the tip of our device. In this article we will focus on this breakdown in more detail.

For example, we will take an electric soldering iron with a power of 40 Watt, designed for a voltage of 220 Volts.

For repair work we will need the following materials and tools:

ceramic resistance PEV-10;
asbestos thread;
pliers (pliers);
hacksaw for metal;
screwdriver;
sharp knife.

Next, we will break down the entire repair process, i.e. replacing the heating element, step by step.

Step one. To replace a failed one, we take a ceramic resistor of the PEV-10 type with a nominal resistance of 1.0 to 1.5 kOhm. The hole located in the center of our resistor has a diameter through which a soldering iron tip can be easily inserted, without any additional adjustment required.

Step number two. Removing the old burnt out heating element. On the metal body protecting the heating element, from the side of the longitudinal seam, we make a transverse cut, approximately to the middle. We retreat from the edge by 4 cm. Then we unfold the sawn sides of the tube and cut off the corners of the resulting nest. This is necessary in order to avoid electrical contact of the metal case with the resistance terminals.

Use an adsense clicker on your websites and blogs or on YouTube

Step three. We insert the PEV-10 resistance, which will serve as a heating element in our soldering iron, into the socket we made. We bend the metal petals of the body, surrounding them with the socket. We secure the resistance in the socket using a clamp.

Fourth step. After carrying out technical measures, we move on to electrical ones. We need to connect to the installed heating element, i.e. Apply voltage to PEV-10. To do this, we clear the wire strands of insulation at a distance of 1.5 - 2 cm from the edge.

Step five. We tightly wrap the loose ends of the wire along the entire length with asbestos thread - turn to turn. We pull the thread-insulated ends of the wire through the handle channels and connect them to the terminals of the new heating element. To make installation easier, bend the resistor leg, insert the pre-stripped end of the wire inside the bent part and crimp it with pliers.

Step number six. We insulate the heater leads with the same asbestos thread, tightly winding them turn to turn. The wires must be laid so that they do not come into contact with the housing. We re-wrap both conductors with thread, fastening them together. Assembling the soldering iron handle. Now our repaired soldering iron is ready for use again.

Have you purchased a soldering iron, but are not satisfied with the quality of its work? Then you will find in this article material on how to repair a soldering iron if you do not want to take it to a workshop, but decide to do it yourself. The video tutorial presented is about a cheap Chinese device in which some parts need to be replaced.

Unusual soldering irons are sold cheaply in a Chinese online store.

First, look at what you need to remake a soldering iron:

- soldering iron;
- thick copper wire;
- screwdriver;
- drill;
- wire;
- wire cutters;
- electrical tape;
- fork;
- flux;
- tin;
- metal sponge.

The first thing we will pay attention to is the ineffective soldering iron tip. We will replace it with a copper wire of the required diameter. Let's take out the old tip and make it out of copper to the same size (thickness and length).

All that remains is to tin the tip and you can solder with the normal soldering apparatus you have modified.

Notes Another disease of Chinese soldering irons is severe overheating during operation. It can be eliminated by inserting into the gap one of the wires a diode with an operating voltage of at least 300 volts (it can be mounted in a power plug; the polarity of the connection does not matter). In order for the soldering iron tip to burn less, before work it must be forged in a cold state with a small hammer; in this case, the copper becomes denser and does not burn so quickly.

DISASSEMBLY AND REWINDING THE SOLDERING IRON

If you, a fellow hobbyist, have already “outgrown” soldering iron with voltage regulator. but I haven’t yet grown up in my ambitions to become a professional soldering station. then this might be interesting. The ability to change the supply voltage of a soldering iron designed for 220 V, among other things, allows you to return to operation an already burnt-out one. And use it in the future, for example, with a switching power supply from an imported TV, which at the output gives exactly half of the network one. Bringing these two products together gives the result intermediate option between a soldering iron with a regulator and a full-fledged soldering station. Any radio amateur can do this. I’ll show you how to do this using the example of changing the supply voltage of a Chinese-made soldering iron, which was not trustworthy for use without modification.

Disassembling the soldering iron

To disassemble the soldering iron, it was necessary to completely unscrew the two screws connecting protective cover with a heating element and holding the tip, and three self-tapping screws securing the working part to the handle. Remove the insulation from the wires and unscrew the connecting twists.

Mica with soldering iron spiral

There is a heating element inside the protective casing. That's what they have to do. It is necessary to change the amount of wound nichrome wire - change the resistance of the heating element. Now it is 1800 Ohms, 400 Ohms are needed. Why exactly so much? Currently working with a UPS, the soldering iron has a resistance of 347 Ohms, its power is from 19 to 28 W, there is a desire to make the second one less powerful, so I added Ohms.

Soldering iron rewind

Winding a soldering iron tip

The tip is reinserted into the heater, clamped with screws and into the drill chuck. If you disassemble and unwind excess nichrome while holding the heating element in your hands, then everything will be much more complicated. The tie wire is removed.

The released fiberglass and mica wrappers are removed. There is a slot in the mica on the side of the tip into which a conductor is inserted, running from the nichrome to the power cable - therefore, the weakened mica wrapper is removed from it rather than unwound. Mica is a very fragile material. The end of the nichrome wire wound to the conductor is disconnected. Its thickness is just over 4 microns.

Nichrome must be wound onto something round, ideal option- spool for thread. I unscrewed it, rewinded it, and so on until the end. There is no need to disconnect the second end of the nichrome wire.

Soldering iron wire resistance

Now you need to wind a length of 400 Ohms, and in centimeters it will be approximately 70 (the total length of nichrome wire 300 cm is 1800 Ohms, hence 400 Ohms will be 66.66 cm). A latch (clothespin) is placed at a length of 70 cm and with the coil hanging in position, slightly guiding it with your fingers, winding is carried out at intervals that ensure its termination at the first conductor. The number of attempts is not limited, the main thing is not to tear the nichrome. At the end of winding, a control measurement of resistance is required.

As soon as I managed to reel required quantities nichrome, cut the wire with an allowance of 1 - 2 cm and wind it to the conductor. We put on the mica winding, passing the conductor into the slot in it and press it against it (naturally on top of it).

We install a fiberglass winding on top and, compacting it by pressing, wind the binding wire. A heating element designed for power supply voltage of 85 - 106 V is assembled.

Soldering iron assembly

Since the working part was previously attached to the handle with incomprehensibly clumsy and short screws, they had to be replaced. To do this, holes were deepened at the attachment points on the handle for new screws.

Before connecting the power cable with the conductors going to the nichrome heater, a plastic clamp was installed and adjusted on it.

The casing of the heating element ends with a kind of cooling radiator, through holes in it and is attached to the handle. To increase the cooling effect, the gap between it and the handle was increased using metal washers.

Soldering iron current consumption 190 mA

The UPS with which the soldering iron will work at the output under load gives from 85 to 106 V. Current consumption is 190 mA, this is at the minimum voltage. Power 16 W.

Soldering iron current consumption 240 mA

At maximum voltage, current consumption is 260 mA. Power 26 W. The desired has been received.

Finally, a test for heating duration. Up to 257 degrees in 2 minutes 20 seconds. An excellent result, if you take into account that from a 225 V network it heated up to 250 degrees in 5 and a half minutes.

Table. Dependence of the resistance of the heating element on the power and voltage of the soldering iron

And here is a table that will help you navigate the required resistance of the heating element, depending on the desired power and the available supply voltage. Author: Babay iz Barnaula.

Many people are guilty of fetishism. Everyone has their own object of adoration. I would venture to guess that for radio amateurs this is most often a soldering iron. I had one like that until I decided to make an improvement - I put a diode in the break in the wire and a toggle switch to it. Well, everyone knows this rationalization and has been for a long time. Convenient, liked it. But the soldering iron burned out. In just a month. It's clear that it's a coincidence. I repaired it - I fastened (crimped) the ends at the burnout site with a piece of copper plate. And a month later again. The second plate did not fit in the heating element. A year has passed. And so, removing a switching power supply from the board of an imported TV, I figured out how to give a second life to a faithful partner - if there is not a sufficient length of whole nichrome wire (and where can I get it with a diameter of 0.08 mm?) to wind the heating element at a voltage of 220V, then this can be made at a lower voltage, for example 110V, from available “scraps” (you need less nichrome).

To begin with, I made measurements and calculations. I measured the resistance of an existing whole piece of nichrome - 367 Ohms. The output voltage of the power supply, took the value of 110V, divided by 367 Ohms and got the required current - 0.3 A, multiplying it by 110V, I found out the estimated possible power of the soldering iron - 33W. Quite enough. The existing mandrel with a dielectric (mica) wound on top was placed in a cartridge hand drill, tied nichrome at one end to a conductor wire, and wound the other on an improvised bobbin, attaching clothespins for weight.

It's not ideal, though. The main thing here is that the turns do not touch each other. The second end of nichrome to the second wire - the conductor. On top of the nichrome there is again a dielectric, of course you need mica, but there wasn’t any - in the photo there is an asbestos cord.

The conductors (wires) are bent in the desired direction, the farthest one is pressed against the asbestos. The contact between conductors - wires must be EXCLUDED. On top is again a dielectric - mica.

Then everything is simple: we pass the wire coming from the plug through the handle of the soldering iron and the casing, and connect its cores by twisting with the conductors in contact with the nichrome, having previously put on the last insulators that were on them before disassembly. We insert everything into the casing.

Handle casing. The tip is inside the heating element mandrel.

Now be sure to “call 9raquo; the pins of the power plug relative to the casing and soldering iron tip! THERE SHOULD BE NO CONTACT.

“Chassis9raquo; the tests were successful. The fact that you shouldn’t plug this soldering iron into a 220-volt outlet is, of course, clear to everyone. A smooth adjustment temperatures, if necessary, are collected according to this scheme. With best wishes, Babay. Russia, Barnaul.

Repairing a burnt soldering iron (for soldering parts), replacing the heating element with your own hands.

Topic: what to do if a soldering iron burns out, how to restore it yourself.

Sometimes the soldering iron you use to solder various schemes, parts, wires suddenly stop working, it does not heat up. In most cases, it may be a simple break in the wire that powers the electric soldering iron itself. The most vulnerable point of the wire is the area where it is frequently bent. For a soldering iron (and not only for it) this is the place where the wire enters the soldering iron itself. You just need to disassemble it and ring the wires coming from the plug. If the wire does not ring, then simply cut off a small piece (about 15 cm long) from the entrance to the soldering iron. Call again. If there is still no contact, then cut the same piece from the plug side. Well, as a last resort, just install a new wire.

But not in all cases, the reason why an electric soldering iron does not work is a break in the wire powering it. Sometimes the heating element itself burns out inside the soldering iron. There are two ways to go here. You can try to rewind the heating coil yourself. This is a fairly simple task if you have something to rewind and if the soldering iron was designed for a voltage no higher than 36 volts. For a soldering iron supply voltage of 220 volts, rewinding the spiral will be much more difficult. A thin and long wire must be carefully wound (so that the turns do not have direct contact) around the base of the heater. For a beginner, this is difficult and time-consuming.

You can go another way. Repairing a burnt soldering iron involves replacing the entire heating element. For example, when the problem of a burnt soldering iron affected me, I went to the aliexpress website, typed in “soldering iron heater” into the search, and then chose the most suitable option(by size, by the power I need and supply voltage). The cost of this heating element was quite low (when compared with buying a new electric soldering iron). Then I placed an order, paid, delivery took about 2 weeks.

Installing a new heating element on a burnt-out soldering iron was not difficult. It fit normally into the base of the soldering iron. Except that the old tip was slightly larger in size than the hole that was on the new heater. I just took a piece copper wire required length and diameter. One end of it (the one that will be soldered) was ground off at an angle. The heating element is fixed with one short screw on one side of the base of the soldering iron. The tip itself is fixed with another screw (slightly longer than the first) on the other side of the base.

The outgoing wires from the heating element were twisted with the wires of the power cord. Having previously put on them small pieces of polyvinyl chloride tube, which has heat-resistant properties. These pieces of tubes act as electrical insulators, which prevent short circuits from occurring at the junction of the wires. Conventional insulation in the form of electrical tape or shrink heat tube will not work, as it will simply collapse when the soldering iron heats up. You can also use fabric or fiberglass tape. That’s basically all the work involved in repairing a burnt-out soldering iron.

P.S. If we talk about what will be cheaper - repair or purchase of a new soldering iron, then repair by replacing a burnt heating element will still cost much less. Whether you can replace it yourself or not is another matter. When purchasing, pay attention to the dimensions of the new heating element, as even a small discrepancy may lead to additional adjustment steps. In addition, make sure that the power and voltage correspond to the values that you need.

Construction and repair of an electric soldering iron

An electric soldering iron is hand tool, intended for fastening parts together using soft solders. by heating the solder to a liquid state and filling the gap between the parts being soldered with it.

Electric soldering irons are produced designed for mains voltages of 12, 24, 36, 42 and 220 V, and there are reasons for this. The main thing is human safety, the second is the network voltage in the place soldering work. In production, where all equipment is grounded and there is high humidity, it is allowed to use soldering irons with a voltage of no more than 36 V, and the body of the soldering iron must be grounded. The motorcycle's on-board network has voltage DC 6 V, passenger car– 12 V, cargo – 24 V. In aviation, they use a network with a frequency of 400 Hz and a voltage of 27 V. There are also design limitations, for example, a 12 W soldering iron is difficult to make for a supply voltage of 220 V, since the spiral will need to be wound from a very thin wire and therefore, if you wind many layers, the soldering iron will turn out to be large, not convenient for small work. Since the soldering iron winding is wound from nichrome wire, it can be powered with either alternating or direct voltage. The main thing is that the supply voltage matches the voltage for which the soldering iron is designed.

Electric soldering irons come in power ratings of 12, 20, 40, 60, 100 W and more. And this is also no coincidence. In order for the solder to spread well over the surfaces of the parts being soldered during soldering, they need to be heated to a temperature slightly higher than the melting point of the solder. Upon contact with a part, heat is transferred from the tip to the part and the temperature of the tip drops. If the diameter of the soldering iron tip is not sufficient or the power of the heating element is small, then, having given off heat, the tip will not be able to heat up to the set temperature, and soldering will be impossible. At best, the result will be loose and not strong soldering. A more powerful soldering iron can solder small parts, but there is a problem of inaccessibility to the soldering point. How, for example, to solder in printed circuit board a microcircuit with a leg pitch of 1.25 mm with a soldering iron tip measuring 5 mm? True, there is a way out: several turns of copper wire with a diameter of 1 mm are wound around such a sting and the end of this wire is soldered. But the bulkiness of the soldering iron makes the work practically impossible. There is one more limitation. At high power, the soldering iron will quickly heat up the element, and many radio components do not allow heating above 70˚C and therefore the permissible soldering time is no more than 3 seconds. These are diodes, transistors, microcircuits.

Soldering iron device

The soldering iron is a red copper rod, which is heated by a nichrome spiral to the melting temperature of the solder. The soldering iron rod is made of copper due to its high thermal conductivity. After all, when soldering, you need to quickly transfer heat from the soldering iron tip from the heating element. The end of the rod is wedge-shaped, is the working part of the soldering iron and is called the tip. The rod is inserted into a steel tube wrapped in mica or fiberglass. A nichrome wire is wound around the mica, which serves as a heating element.

A layer of mica or asbestos is wound over the nichrome, which serves to reduce heat loss and electrically insulate the nichrome spiral from the metal body of the soldering iron.

ends nichrome spiral connected to the copper conductors of an electrical cord with a plug at the end. To ensure the reliability of this connection, the ends of the nichrome spiral are bent and folded in half, which reduces heating at the junction with the copper wire. In addition, the connection is crimped with a metal plate; it is best to make the crimp from an aluminum plate, which has high thermal conductivity and will more effectively remove heat from the joint. For electrical insulation, tubes made of heat-resistant insulating material, fiberglass or mica are placed at the junction.

The copper rod and nichrome spiral are closed with a metal case consisting of two halves or a solid tube, as in the photo. The body of the soldering iron is fixed on the tube with cap rings. To protect a person’s hand from burns, a handle made of a material that does not transmit heat well, wood or heat-resistant plastic, is attached to the tube.

When inserting the soldering iron plug into the outlet electric current goes to a nichrome heating element, which heats up and transfers heat to the copper rod. The soldering iron is ready for soldering.

Low-power transistors, diodes, resistors, capacitors, microcircuits and thin wires are soldered with a 12 W soldering iron. Soldering irons 40 and 60 W are used for soldering powerful and large-sized radio components, thick wires and small parts. To solder large parts, for example, heat exchangers of a geyser, you will need a soldering iron with a power of one hundred or more watts.

Electrical circuit of a soldering iron

As you can see in the drawing, the electrical circuit of the soldering iron is very simple, and consists of only three elements: a plug, a flexible electrical wire and a nichrome spiral.

As can be seen from the diagram, the soldering iron does not have the ability to adjust the heating temperature of the tip. And even if the power of the soldering iron is chosen correctly, it is still not a fact that the temperature of the tip will be required for soldering, since the length of the tip decreases over time due to its constant refilling; solders also have different melting temperatures. Therefore, in order to maintain the optimal temperature of the soldering iron tip, it is necessary to connect it through thyristor power regulators with manual adjustment and automatic maintenance of the set temperature of the soldering iron tip.

Calculation and repair of the heating winding of a soldering iron

During repairs or self-production An electric soldering iron or any other heating device requires winding a heating winding made of nichrome wire. The initial data for calculating and selecting wire is the winding resistance of a soldering iron or heating device, which is determined based on its power and supply voltage. You can calculate what the winding resistance of a soldering iron or heating device should be using the table.

Knowing the supply voltage and measuring the resistance of any heating electrical appliance, such as a soldering iron or electric kettle. electric heater or electric iron. you can find out the consumption of this household electrical appliance power. For example, the resistance of a 1.5 kW electric kettle will be 32.2 Ohms.

Table for determining the resistance of a nichrome spiral depending on power and supply voltage electrical appliances, Ohm

Power consumption
soldering iron, W

Let's look at an example of how to use the table. Let's say you need to rewind a 60 W soldering iron designed for a supply voltage of 220 V. In the leftmost column of the table, select 60 W. From the top horizontal line, select 220 V. As a result of the calculation, it turns out that the resistance of the soldering iron winding, regardless of the winding material, should be equal to 806 Ohms.

If you needed to make a soldering iron from a 60 W soldering iron, designed for a voltage of 220 V, for power supply from a 36 V network, then the resistance of the new winding should already be equal to 22 Ohms. You can independently calculate the winding resistance of any electric heating device using an online calculator.

Online calculator for calculating the resistance value based on power consumption

Supply voltage, V:

After determining the required resistance value of the soldering iron winding, the appropriate diameter of the nichrome wire is selected from the table below, based on the geometric dimensions of the winding. Nichrome wire is a chromium-nickel alloy that can withstand heating temperatures up to 1000˚C and is marked X20N80. This means that the alloy contains 20% chromium and 80% nickel.

Table of dependence of linear resistance (one meter) of nichrome wire on its diameter

Diameter of nichrome wire, mm

To wind a soldering iron spiral with a resistance of 806 Ohms from the example above, you will need 5.75 meters of nichrome wire with a diameter of 0.1 mm (you need to divide 806 by 140), or 25.4 m of wire with a diameter of 0.2 mm, and so on.

When winding a soldering iron spiral, the turns are laid close to each other. When heated red-hot, the surface of the nichrome wire oxidizes and forms an insulating surface. If the entire length of the wire does not fit on the sleeve in one layer, then the wound layer is covered with mica and a second one is wound.

For electrical and thermal insulation of heating element windings the best materials is mica, fiberglass cloth and asbestos. Asbestos has an interesting property: it can be soaked with water and it becomes soft, allows you to give it any shape, and after drying it has sufficient mechanical strength. When insulating the winding of a soldering iron with wet asbestos, it is necessary to take into account that wet asbestos conducts electrical current well and it will be possible to turn on the soldering iron into the electrical network only after the asbestos has completely dried.

An electric soldering iron is manual equipment, which allows you to connect parts together using soft solders, heating the solder to a liquid consistency, filling the voids between the elements being connected. Before purchasing a tool, you need to familiarize yourself with the technical characteristics of the device, operating instructions and how to repair a soldering iron.

A soldering iron is a tool needed to perform minor repairs electronic devices.

terms of Use

There are models on the market that are suitable for operation from a network with voltages from 12 to 220 V. In the process of choosing a tool, the need to ensure the safety of the craftsmen working with it and the voltage in the electrical network at the work site are taken into account.

In rooms with high humidity levels and grounded devices, it is permissible to use a soldering iron with a voltage of up to 36 V and mandatory grounding of the soldering iron body. There is no need to repair the instrument if these requirements are met.

When making your own soldering iron, a thin wire is used to wind the spiral. The supply and tool voltages must match each other. The power of such units reaches from 12 to 100 W and higher, because it is possible to ensure that the solder spreads evenly over the surface of the elements being connected if they are heated above its melting point. Heat from the tip is transferred to the parts upon contact, because of this the temperature of the tip decreases.

Insufficient power of the heating coil or small diameter of the rod may prevent the tip from heating to the required temperature, which prevents soldering. Powerful soldering irons can be used to connect small parts, but due to the size of the device, access to the soldered elements is limited. Experts recommend winding a copper wire with a diameter of 1 mm around the tip. High power similar devices allows you to quickly warm up elements, and most small radio components, transistors, diodes, microcircuits cannot withstand temperatures exceeding 70 ° C. Soldering time is reduced to 3 seconds. Before you repair the device in question, you will need to find out its design features.

Return to contents

Components

The device in question is made of a copper rod, which is heated to the melting temperature of the solder using a nichrome spiral. When soldering parts, it is necessary to ensure that heat is quickly transferred from the heating element to the tip.

The tip is the working part of the tool, a rod with a wedge-shaped tip. It is inserted into a steel tube wrapped in fiberglass cloth or mica, on which a wire is wound, which acts as a heating element. Nichrome wire is wrapped with asbestos, which helps reduce heat loss. The ends of a nichrome spiral are attached to the conductors of the electrical cord with a plug, which are bent and folded in half to ensure greater reliability and reduce the heating temperature at the points of connection with the copper wire. The connection is additionally crimped with a metal plate.

The spiral made of a nickel-chromium alloy and the sting made of copper are located in a metal casing, which can be made from a solid piece of metal or welded from 2 parts. The housing is fixed to the metal tube using overlay rings. Electric current after inserting the plug of the device into the socket is supplied to a nichrome spiral, which, after heating, transfers heat to the tip.

Experts recommend using equipment with a power of no more than 12 W for soldering low-power diodes. Thick wires, large parts and small powerful parts need to be soldered using 40 and 60 W devices. Large parts are soldered with units of 100 W or more.

The quality of work cannot be guaranteed by the selection of tools correct power. Incorrect operation of the unit leads to breakdown and the need to repair the soldering iron.

Return to contents

Step by step instructions

Independent production or repair of heating devices is carried out taking into account the calculation of the resistance of the heating element or winding. Knowing the voltage and resistance values of an electrical appliance allows you to calculate its power that it consumes. The resistance in the winding of a 60 W soldering iron, powered by a 36 V network, should reach 22 Ohms. Correct selection power and voltage helps to avoid breakdowns and the need to repair the device in question.

Schemes of temperature controllers for the soldering iron tip.

Then you need to select the diameter of the nichrome wire, comparable to the dimensions of the winding. The spiral winding with a resistance of 806 Ohms is performed using 5.75 m of wire with a diameter of 0.1 mm (the resistance value is divided by 140) or 25.4 m of wire with a diameter of 0.2 mm. The coils must be laid closely. The surface of the nichrome wire will oxidize when heated, creating an insulating surface. The wound layer, which does not fit into the first row, is covered with mica. Wind up the second row. High-quality assembly allows you to operate the tool for a long time without breakdowns or repairs.

Thermal and electrical insulation in the winding is provided by a coating made of fiberglass, mica or asbestos. The advantage of asbestos over other compounds is that it can be soaked with water, creating the required shape, and after drying, the material has a fairly high strength.

The main cause of soldering iron malfunction is a broken heating element.

Simple repairs help restore its functionality. To repair a soldering iron, you will need the following tools:

pliers;
sharp knife;
ceramic resistance “PEV-10”;
asbestos thread.

Repair of an electric soldering iron is carried out in several stages. A 1-1.5 Ohm ceramic resistor is pre-prepared. In its central part there is a hole that allows you to pass the soldering iron rod without additional adjustment.

The faulty heating element is then removed. A prepared ceramic resistor is placed in the resulting socket. The next step is to connect the power wires to the resistor. To do this, it is recommended to use the channels in the handle of the device. The wires must be laid so that they do not come into contact with the body, and the terminals must be insulated with asbestos thread. Upon completion of the repair work, you will need to assemble the components of the soldering iron in the reverse order. To repair a soldering iron yourself, you will need its circuit diagram.

An electric soldering iron is a hand-held tool designed for fastening parts together using soft solders, by heating the solder to a liquid state and filling the gap between the parts being soldered with it.

As you can see in the drawing, the electrical circuit of the soldering iron is very simple, and consists of only three elements: a plug, a flexible electrical wire and a nichrome spiral.

Soldering iron device

A layer of mica or asbestos is wound over the nichrome, which serves to reduce heat loss and electrically insulate the nichrome spiral from the metal body of the soldering iron.

The ends of the nichrome spiral are connected to the copper conductors of an electrical cord with a plug at the end. To ensure the reliability of this connection, the ends of the nichrome spiral are bent and folded in half, which reduces heating at the junction with the copper wire. In addition, the connection is crimped with a metal plate; it is best to make the crimp from an aluminum plate, which has high thermal conductivity and will more effectively remove heat from the joint. For electrical insulation, tubes made of heat-resistant insulating material, fiberglass or mica are placed at the junction.

When you insert the soldering iron plug into a socket, electric current flows to the nichrome heating element, which heats up and transfers heat to the copper rod. The soldering iron is ready for soldering.

Soldering iron supply voltage

There are also design limitations, for example, it is difficult to make a 12 W soldering iron with a supply voltage of 220 V, since the spiral will need to be wound from a very thin wire and therefore many layers will be wound; the soldering iron will turn out to be large and not convenient for small work. Since the soldering iron winding is wound from nichrome wire, it can be powered with either alternating or direct voltage. The main thing is that the supply voltage matches the voltage for which the soldering iron is designed.

Soldering iron heating power

A more powerful soldering iron can solder small parts, but there is a problem of inaccessibility to the soldering point. How, for example, can you solder a microcircuit with a leg pitch of 1.25 mm into a printed circuit board with a soldering iron tip measuring 5 mm? True, there is a way out: several turns of copper wire with a diameter of 1 mm are wound around such a sting and the end of this wire is soldered. But the bulkiness of the soldering iron makes the work practically impossible. There is one more limitation. At high power, the soldering iron will quickly heat up the element, and many radio components do not allow heating above 70˚C and therefore the permissible soldering time is no more than 3 seconds. These are diodes, transistors, microcircuits.

DIY soldering iron repair

The soldering iron stops heating for one of two reasons. This is a result of chafing of the power cord or burnout of the heating coil. Most often the cord frays.

Checking the serviceability of the power cord and soldering iron coil

When soldering, the power cord of the soldering iron is constantly bent, especially strongly at the point where it exits and the plug. Usually in these places, especially if the power cord is hard, it frays. This malfunction first manifests itself as insufficient heating of the soldering iron or periodic cooling of it. Eventually, the soldering iron stops heating.

Therefore, before repairing the soldering iron, you need to check the presence of supply voltage in the outlet. If there is voltage in the outlet, check the power cord. Sometimes a faulty cord can be determined by gently bending it at the point where it exits the plug and soldering iron. If the soldering iron becomes a little warmer, then the cord is definitely faulty.

You can check the serviceability of the cord by connecting the probes of a multimeter turned on in resistance measurement mode to the pins of the plug. If the readings change when bending the cord, the cord is frayed.

If it is discovered that the cord is broken at the point where it exits the plug, then to repair the soldering iron it will be enough to cut off part of the cord along with the plug and install a collapsible one on the cord.

If the cord is frayed at the point where it exits the soldering iron handle or the multimeter connected to the pins of the plug does not show resistance when bending the cord, then you will have to disassemble the soldering iron. To gain access to the place where the spiral is connected to the cord wires, it will be enough to remove only the handle. Next, touch the multimeter probes successively to the contacts and pins of the plug. If the resistance is zero, then the spiral is broken or its contact with the cord wires is poor.

Calculation and repair of the heating winding of a soldering iron

When repairing or making your own electric soldering iron or any other heating device, you have to wind a heating winding made of nichrome wire. The initial data for calculating and selecting wire is the winding resistance of a soldering iron or heating device, which is determined based on its power and supply voltage. You can calculate what the winding resistance of a soldering iron or heating device should be using the table.

Knowing the supply voltage and measuring the resistance of any heating electrical appliance, such as a soldering iron, electric kettle, electric heater or electric iron, you can find out the power consumed by this household electrical appliance. For example, the resistance of a 1.5 kW electric kettle will be 32.2 Ohms.

Table for determining the resistance of a nichrome spiral depending on the power and supply voltage of electrical devices, Ohm
Power consumption soldering iron, W	Soldering iron supply voltage, V
Power consumption soldering iron, W	12	24	36	127	220
12	12	48,0	108	1344	4033
24	6,0	24,0	54	672	2016
36	4,0	16,0	36	448	1344
42	3,4	13,7	31	384	1152
60	2,4	9,6	22	269	806
75	1.9	7.7	17	215	645
100	1,4	5,7	13	161	484
150	0,96	3,84	8,6	107	332
200	0,72	2,88	6,5	80,6	242
300	0,48	1,92	4,3	53,8	161
400	0,36	1,44	3,2	40,3	121
500	0,29	1,15	2,6	32,3	96,8
700	0,21	0,83	1,85	23,0	69,1
900	0,16	0,64	1,44	17,9	53,8
1000	0,14	0,57	1,30	16,1	48,4
1500	0,10	0,38	0,86	10,8	32,3
2000	0,07	0,29	0,65	8,06	24,2
2500	0,06	0,23	0,52	6,45	19,4
3000	0,05	0,19	0,43	5,38	16,1

I note that when heated by every 100°, the resistance of nichrome increases by 2%. Therefore, the resistance of the 806 Ohm spiral from the above example, when heated to 320˚C, will increase to 854 Ohms, which will have virtually no effect on the operation of the soldering iron.

For electrical and thermal insulation of the heating element winding, the best materials are mica, fiberglass cloth and asbestos. Asbestos has an interesting property: it can be soaked with water and it becomes soft, allows you to give it any shape, and after drying it has sufficient mechanical strength. When insulating the winding of a soldering iron with wet asbestos, it is necessary to take into account that wet asbestos conducts electrical current well and it will be possible to turn on the soldering iron into the electrical network only after the asbestos has completely dried.

An electric soldering iron is a well-known heating device designed for joining a wide variety of parts made of non-ferrous or ferrous metals.

The operating principle of the tool is based on the heating effect of its working tip (tip), which melts the solder with flux. The resulting liquid mixture fills all the unevenness and voids between the parts and forms a reliable connection after cooling.

But during operation, the tool may break, and such damage manifests itself in the most various forms. That's why do-it-yourself repair soldering iron is a mandatory operation that any master working with it must master.

In order to quickly and efficiently repair an electric soldering iron with your own hands, first of all, you need to familiarize yourself with its design, which includes the following components:

an electric heating element placed on a tubular base made of mica or fiberglass and made in the form of a twisted spiral winding;
handle-holder with holes for a tubular base and an electric cord;
a working tip inserted from the other end of the mica tube.

On top of the nichrome wire, another protective layer of mica or asbestos is made, which reduces heat loss and insulates the spiral from metal parts housings.

The ends of the winding are folded in half and soldered to the copper conductors of an electrical cord with a plug at the mating end. To prevent them from accidentally tearing, these places are reinforced with aluminum plates compressed under pressure, which remove excess heat from the contact area.

For better insulation, special tubes (ceramic or made of fiberglass or mica) are put on the wire connection areas.

Electrical diagram

To understand the basics of repairing a soldering fixture, it is advisable to familiarize yourself with its diagram, which consists of a number of elements connected in series. It consists of electrical plug, connecting wire (cord) and heating winding made of nichrome.

Since the power comes from a 220 V AC network, a converter is usually built into the circuit.

Voltage

One of the main technical characteristics What is taken into account when it is necessary to repair a soldering iron is the voltage supplied to the winding. IN various models devices it can take the following values:

220 Volt (used in most domestic models);
supply voltages reduced by a transformer ranging from 12 to 42 Volts (for hazardous working conditions);
5-volt power supply for, which is not difficult to repair at home.

Reduced voltages are used in conditions called dangerous and especially dangerous (when high levels humidity or dustiness of the room, for example). The main purpose of reducing this value is to protect the user from electric shock.

Regardless of which of these models is subject to repair, the methods for restoring it come down to simple work operations.

Power

Electrical power refers to the energy taken from the network by a soldering iron, defined as the product of voltage and consumed current.

This indicator is directly related to the thermal power dissipated by the tip, which determines its operational capabilities. The larger this parameter, the better the soldering iron tip will warm up the soldering area.

The operating power values for various product samples vary within very wide limits (from units to thousands of watts).

That is, there is a choice when to work with small details preference is given to soldering devices with low heat consumption and dissipation. Well, for cases when you have to solder large metal products, on the contrary, only “powerful” devices are suitable.

Taking this indicator into account in the simplest case comes down to replacing the tip with a thicker tip or vice versa. If the heating element fails, the power is taken into account when it is necessary to rewind it independently and select the required number of turns.

Winding calculation

Repairing a soldering iron in most cases comes down to a procedure that allows you to rewind a burnt nichrome winding. When replacing it, it is important to correctly select the thickness and diameter of the nichrome wire, as well as the number of turns in the spiral, which determines the generated thermal power.

When calculating and selecting the required wire diameter, we proceed from the resistance value of the heating winding of the soldering iron, which, in turn, is determined by its operating power (supply voltage).

To determine the initial indicator (winding resistance), special tables are used.

Table for determining the resistance of a nichrome spiral depending on the power and supply voltage of electrical devices, Ohm
Power consumption soldering iron, W	Soldering iron supply voltage, V
Power consumption soldering iron, W	12	24	36	127	220
12	12	48,0	108	1344	4033
24	6,0	24,0	54	672	2016
36	4,0	16,0	36	448	1344
42	3,4	13,7	31	384	1152
60	2,4	9,6	22	269	806
75	1.9	7.7	17	215	645
100	1,4	5,7	13	161	484
150	0,96	3,84	8,6	107	332
200	0,72	2,88	6,5	80,6	242
300	0,48	1,92	4,3	53,8	161
400	0,36	1,44	3,2	40,3	121
500	0,29	1,15	2,6	32,3	96,8
700	0,21	0,83	1,85	23,0	69,1
900	0,16	0,64	1,44	17,9	53,8
1000	0,14	0,57	1,30	16,1	48,4
1500	0,10	0,38	0,86	10,8	32,3
2000	0,07	0,29	0,65	8,06	24,2
2500	0,06	0,23	0,52	6,45	19,4
3000	0,05	0,19	0,43	5,38	16,1

Using these tables, you can check the correctness of the winding calculations in order to carry out repairs in the future.

With a fixed supply voltage U and the resistance of the heating device R measured using a tester, the power P consumed by it is calculated using the formula P=(UxU)/R.

Possible faults

The most common malfunction of soldering irons (regardless of type and power) is burnout of the heater winding or partial interturn short circuit.

It manifests itself in the fact that the soldering iron does not heat up at all, that is, it loses its functionality.

As a rule, the short circuit of individual turns over time also leads to the burning of the entire spiral, when ordinary repairs will no longer help, and the spiral must be completely rewinded. At the most favorable conditions The lack of heating of the soldering iron may be due to the following reasons:

poor contact at the junction of the voltage supply wire and the ends of the winding (spiral);
faulty power plug;
a break in one of the cores in the cord itself.

All these malfunctions are detected through visual inspection, or using a tester turned on in the “Ring” mode, after which repairs are made.

Sequence of repair work

To eliminate a break in the wires or plug, first use a multimeter (tester) to identify the exact location of the damage. And only after that one of the possible ways soldering iron repair.

So, if a break is detected in the supply wire or plug, the easiest way is to completely replace these parts with a working product. To do this, it is more convenient to simply extend the undamaged part by soldering a new power cord to it.

When extending the lead wire special attention is given to the insulation of individual cores. The most reliable way to protect each of them is with a polyvinyl chloride tube (cambric).

If the soldering iron winding burns out, you will have to open the protective casing (cover) and completely disassemble the heating element, disconnecting it from the power wires.

When rewinding a spiral, you must carefully ensure that adjacent turns are located at a distance from one another, and a mica spacer is placed between the winding rows.

At the end of the winding work, the leads are soldered to the ends of the nichrome wire, and then the supply wires are crimped, after which the protective casing returns to its original place. At this point the repair can be considered complete.

Operating rules

When working with an electric soldering iron, in order to avoid accidental breakdowns of individual parts, you must adhere to the following rules:

During soldering, avoid strong mechanical stress on the cord and the electric heater of the device.
Do not overheat the soldering iron coil (do not leave it on for a long time).
It is necessary to use a power regulator that allows you to select the required mode for heating the tip.

In conclusion, we note that during operation it is necessary to monitor the condition of the power cord and prevent it from being accidentally damaged by contact with hot water. high temperature sting.

If this cannot be avoided, you should carefully isolate the melted area by placing a cambric over the damaged core and wrapping it with electrical tape.

A simple repair will help get your soldering iron working again. In general, thanks to its simple design, this tool rarely fails.