An electric soldering iron is available in every household. home handyman. You can’t do without it either when repairing electrical devices or 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 a 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.
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.
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 temperatures melting. Therefore, to maintain optimal temperature soldering iron tips have to be connected through thyristor power regulators with manual adjustment and automatic maintenance of the set temperature of the soldering iron tip.
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 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.
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 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, heat-resistant tubes are placed at the connection point. insulating material, fiberglass or mica.
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 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.
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.
Soldering iron supply voltage
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 at the place where the soldering work is performed. 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 on-board network of the motorcycle has a DC voltage of 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, 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, not convenient for small work. Since the soldering iron winding is wound from nichrome wire, it can be powered either by AC or constant voltage. The main thing is that the supply voltage matches the voltage for which the soldering iron is designed.
Soldering iron heating power
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 the problem arises 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 its periodic cooling. 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 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
During repairs or self-production 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, for example a soldering iron, 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 | Soldering iron supply voltage, V | |||||
| 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 | |
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.
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.
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.
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.
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 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 electric current well and it will be possible to turn on the soldering iron into the electrical network only after the asbestos has completely dried.
Nowadays, polymer channels are increasingly used when creating various pipelines. They have many advantages over their metal counterparts. Special attention deserve polymer pipes. The price per 1 meter of these structures is significantly lower than that of metal analogues. Their distinctive feature is convenient installation. Such pipe structures are soldered using
In this article we will analyze the structure of the mentioned device, list the most popular manufacturers of equipment and tell you how to fix the most typical breakdown yourself. You will also have the opportunity to watch photos and videos on the topic of this material.
Device structure
Most soldering machines have approximately the same design. The differences lie only in the shape and methods of installing special attachments.
Any soldering iron for polypropylene pipes comprises:
- housings and handles;
- thermostat;
- heating element placed in a metal casing;
- replaceable nozzles coated with Teflon.
In terms of their method of operation, the devices in question are much like a regular iron.
Some experts call these devices that way. The operation of the device is quite simple. The heating element increases the temperature of the stove inside which it is located. From it, heat is transferred to the nozzles. It is these heating elements that help soften the polymer to the desired consistency.
The thermostat allows you to control the heating process. This part is responsible for supporting the necessary temperature regime, preventing overheating of the installed nozzles. If the thermostat is faulty, it will be difficult to operate the device. Heating elements can become very hot. This will negatively affect the duration of their operation. The metal part of the stove will begin to melt over time. As a result, the device will become unusable.
It is important to choose a soldering machine equipped with a high-quality thermostat. In cheap models, this element is unstable. This leads to uneven heating of polypropylene structures. The temperature level may be excessively high or, conversely, low.
Note that for experienced specialists such a defect is not critical. At the same time, beginners will be able to effectively complete the task only with the use of an absolutely working soldering iron. This is due to the fact that professionals intuitively work with the device, and thanks to their skills they will be able to minimize the consequences of using an unstable device.
Based on what was written above, a simple conclusion is drawn - it is better to use high-quality and reliable equipment than to tinker with a poorly functioning soldering iron. In this case, it is advisable to use equipment with a thermostat that allows smooth temperature control.
Typical failure: the soldering machine does not heat up
Let's look at a real case of repair of the RSP-2a-Pm device from the Czech company Wavin ekoplastik. The problem was this: the device was heating up, but did not reach the required temperature. At the same time, during operation, the sound of sparking contacts arose inside the device. The device was used intensively for a year.
The repair of the device began with its disassembly. Next it was necessary to establish the cause of the malfunction. First the control board was checked. Next, the soldering iron was turned on and the voltage indicator at the output of the mentioned circuit was determined.
When performing the test, you do not need to wait until the tip is completely warmed up. A similar procedure would be appropriate when testing electronics. In our example, it was only necessary to determine the cause of the breakdown. After checking the board, it would be necessary to move on to diagnosing the heating element.
The soldering machine in question was switched on. The heating indicators lit up clearly. It was assumed that the problem lies in the heating element circuits. To accurately identify the breakdown, it was necessary to disassemble the protective grille of the heating element.
It was decided to check the thermostat screwed to the heater. The main task of this component is additional protection. The operation of the device was completely controlled electronically. The thermostat was installed in order to avoid uncontrollability of the heating element in case of damage to the thyristor.
If the maximum permissible temperature the bimetallic contacts of the safety device will open and the main heating component will stop operating. In a specific case, the mentioned elements burned. As a result, contact opening began to occur at temperatures below the limit. That's what it was main reason constant underheating of the device.
To eliminate this problem, it was possible to repair the thermostat. But this task is very difficult and time-consuming. Replacing the element in question was not feasible due to the lack of spare parts.
As a result, the repairman decided to remove the thermostat from the circuit and connect it directly. To do this, the element was disconnected from the heating element contact. Then a new terminal, purchased in a store, was crimped onto another wire, of blue color. To solve this problem, it is possible to use insulated terminals.
Try to use exclusively heat-resistant cambrics. They must withstand high temperatures.
The terminals are crimped using special pliers. If worst comes to worst, you can also use pliers. The main thing is that the procedure is performed efficiently and reliably. After its implementation, the cable in the terminal must be motionless.
After completing the procedure for turning off the thermostat, it was necessary to assemble the device. During the process, it was discovered that the wire clamp was damaged. To eliminate this damage, a regular plastic clamp was used. After fixing the cables, the excess parts of the plastic were cut off.
Next, the assembly of the device was completed. After this, the device was tested for serviceability. The soldering iron worked like clockwork again. You can use the information from this article for repairs. various models soldering irons
Watch the video:
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 for a lower voltage, for example 110V, from available “scraps” (after all, less nichrome is needed).
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.
This is not ideal, but... the main thing here is that the turns do not touch each other. The second end of the 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 the conductors and 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 “ring” the pins of the power plug relative to the casing and soldering iron tip! THERE SHOULD BE NO CONTACT.
The “running” tests were successful. The fact that you shouldn’t plug this soldering iron into a 220-volt outlet is, of course, clear to everyone. And smooth temperature control, if necessary, is achieved according to this scheme. With best wishes, Babay. Russia, Barnaul.
An electric soldering iron is a hand-held equipment that allows you to soft solders connect parts together, heating the solder to a liquid consistency, filling the voids between the elements being connected. Before purchasing a tool, you should familiarize yourself with technical characteristics device, operating rules 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 level humidity 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 uniform spreading of solder 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. The high power of such devices allows you to quickly warm up the 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 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. Electricity after inserting the plug of the device into the socket, it enters 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 instruction
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 long time operate the tool 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 housing, and the terminals must be insulated with asbestos thread. Upon completion of the repair work, you will need to collect constituent elements soldering iron in reverse order. To repair a soldering iron yourself, you will need its diagram.