Homemade powerful soldering iron for 220V. Homemade miniature low-voltage soldering iron. At high frequency

The phrase “Soldering iron made from a resistor” correlates quite adequately with the phrase “Money out of thin air.” The meaning is the same - to get something from nothing. This is not a crazy attempt to “overthrow” the huge assortment that is on the shelves of stores selling electrical products. However, there is for now, but not everywhere, and where there is now may not be later. Life is a changeable thing, especially since even the most expensive one can burn out at such an inopportune moment - so to speak, in the most interesting place. And PEV resistors (wire - enameled - moisture resistant) were, are and will be. So, there is no need to renounce.

Here they are “two from the casket”. The resistance of the left, formerly a resistor, and now a heating element is 1019 Ohm; at a voltage of 220V it consumes 210mA and its real power is 46.2W. The resistance of the heating element of the second soldering iron is 1553 Ohm, at 220V the current consumption is 140mA and this will be 30.8W. Using them is very convenient and comfortable in tandem with a power regulator. Heaters made from PEV resistors can withstand heating temperatures incomparably higher than the melting point of tin. I suspect that a method has been invented to turn these resistors into heating elements at the same time they are being manufactured. This technology for manufacturing soldering irons has not received widespread use among radio amateurs, and the reason for this is the difficulty in choosing, let alone making, suitable holders (handles) for such soldering irons. The difficulty lies in the choice of material and in the design itself.

But if you manage to find something suitable for the case - the holder of the future soldering iron, then the manufacturing process comes down to the elementary fixation of the voltage supply wires by twisting them with the contacts of the resistor.

Here the case - the holder is a former connecting plug - the “mother” from the three-program radio “Electronics”.

And here the holder has always been there, but only in the device for welding plastic film. Where it also uses a powerful PEV resistor as a heater, and the product is industrially manufactured.

It is not at all necessary to determine the required resistor value from the very beginning using the selection method; you can roughly calculate it. It is quite acceptable to “push off” from the measurements given above. So, with a soldering iron power of 30.8 W, the resistor resistance is 1553 Om. But you need, for example, exactly 30W. We consider the method of calculating proportions, but not direct, but inverse. Indeed, in this case, a decrease in (power) is achieved by increasing (resistance).

To simplify possible further calculations, I suggest rounding the value of 1594.4 Om to 1600 Om - the calculations will still not be entirely accurate, +/- a couple of watts in power.

P, W D L H d
PEV 3 14 26 28 5.5
PEV 7.5 14 35 28 5.5
PEV 10 14 41 28 5.5
PEV 15 17 45 31 8
PEV 20 17 50 31 8

A soldering iron made from a PEV resistor does not need to be grounded, it will not break through to ground, the main thing is to well insulate its contacts at the point of connection with the power wires. Moreover, it is not necessary to use 220V for heating. For example: if you take a PEV 7.5 resistor with a resistance of 75 Ohms for a soldering iron and apply 12 volts of DC voltage to it, you will get a miniature soldering iron, convenient for use, with a current consumption of 500 mA and a heating element power of just over 7 W. Not everyone has an electrical goods store near their home and not everyone lives in cities, but this is not a reason not to have the necessary soldering iron. Talked about daily matters, Babay.

Discuss the article HOW TO MAKE A SOLDERING IRON

A soldering iron is an empty phrase for many, but for most men it is an indispensable tool in everyday life. And it doesn’t even matter whether you are repairing electronics, or just an inquisitive mind doesn’t give you rest. In this article we will talk about creating a soldering iron with your own hands from scrap materials. But let’s immediately say that it’s easier to buy, it will be more reliable and safer for your health.

1 ) How to make a soldering iron with your own hands - schematic diagram of a soldering iron

As you can see, the soldering iron is very simple in terms of design and all you need for it is self-assembly at home, it can be found in every home.

How to make a soldering iron with your own hands - what you need

Our current soldering iron model will run on a 12-14 volt battery. This is much safer than using a voltage of 220 volts in a homemade soldering iron.

Li-ion battery(quite suitable from a power tool or an old laptop).
A piece of single-core copper wire with a diameter of about two millimeters and a length of five to six centimeters. We will need it to wind the spiral.
Heat-resistant fiberglass tubes with different diameters of 3.8 and 1 millimeter to isolate the heating element from the metal casing (you can take it from an electric kettle).
Nichrome wire with a diameter of 0.3 millimeters (can be taken from an old hair dryer). We will select the length of the wire experimentally depending on the power of the soldering iron and battery.
A section of a telescopic antenna from a radio receiver with a diameter of 4 millimeters and a length of 3 centimeters.
A piece of copper single-core wire for the tip, with a diameter of 3.8 millimeters.
Wire for connecting power to the soldering iron.
Wooden or plastic tube for the handle.

How to make a soldering iron with your own hands - assembly

First, we will start making the heating element.
We wind a nichrome thread around a piece of wire and by selecting the length of the spiral we achieve heating within the range of 300 - 450 degrees Celsius.

Let's take the same piece of single-core copper wire and put a heat-resistant tube on it.
We wind the piece of spiral we selected onto the tube.

We put thinner tubes on the ends of the spiral and place the entire structure inside another, thicker tube. Let's take out the copper wire (it has fulfilled its role and we no longer need it).

That's it, the heating element is ready. Now all that remains is to insert it inside the copper tube from the antenna and place our tip in it. We fix the tip in the tube with a self-tapping screw.

Our soldering iron is almost ready. All that remains is to attach the power wire to the ends of the spiral, insert the entire structure into the handle and connect to the power source.

Important: some non-flammable material must be placed between the handle and the antenna tube to avoid a fire. ZMP is quite suitable for this purpose.

Let's summarize all of the above. To create a soldering iron, you do not need any special knowledge or expensive components. But such homemade products should only be done when you need to solder something, but you simply don’t have a soldering iron at hand. And there is simply no time to go shopping to purchase it. In all other cases, it is easier to buy it, especially since it does not cost a lot of money. But in terms of safety, the factory one is much more reliable than any kind of homemade product.

I recommend to readers of the magazine an easy-to-calculate, easy-to-manufacture and very reliable electric soldering iron. For example, I have several of these at home: from a “tiny one” for working with microelectronics to a powerful “cleaver”, with which I patch leaky metal tanks, repair well filters and other large parts. Moreover, the heating element of each electrical appliance is... a resistor of appropriate power (type PE or PEV), powered from a household electrical network with a voltage of 220 V. The quenching resistances, if you cannot do without them, are reactive, or more precisely, capacitive, allowing you to solve quite complex electrical problems with minimum sizes the devices themselves.

As practice has shown, to carry out calculations in the manufacture of soldering irons with resistor heaters, it is enough to know Ohm’s law (I=U/R), the elementary power formula (P=IU) and to be able to use the four operations of arithmetic well.

Let’s assume that, having a vitrified resistor PEV30 with a nominal value of 100 Ohms, you decided to use it to make a soldering iron to operate from a 220 V mains voltage. Referring to the above ratios, it is not difficult to determine the required data: current 2.2 A, power consumption 484 W. But…

The 30-watt parameter appearing in the name of the resistor used is the dissipation power at which the PEVZO can long time(thousands of hours!) maintain its nominal value without noticeably heating up. Mounted as a heater in a soldering iron (of course, with an inserted copper heat sink rod), this resistor should and can dissipate power many times greater than the rated power.

True, 484 W will also be too much for him - it will melt. Taking this into account, we will reduce (for example, four times) the power per 100-ohm PEV30 by connecting a special damping resistance in series with it. Then the current that will flow through such a circuit will also decrease and become equal, according to calculations, to 0.55 A. This means that the voltage drop across the resistor-heater will now be only 55 V.

But the network is 220 V. Consequently, 165 V is the share of the damping resistance, the nominal value of which, according to the law of electrical engineering known from school, should be equal to 300 Ohms. As such a chain element it is impossible would be better suited capacitor (for example, MBGCh type), designed for an operating voltage of 250-300 V.

From theory we know that the equivalent resistance of a 1 µF capacitor at a frequency of 50 Hz is approximately 3 kOhm. We need 300 Ohms. Taking this into account, we choose the capacity of the quenching capacitor 10 times larger, that is, equal to 10 μF.

So, the necessary data has been obtained. Now you can proceed directly to making the soldering iron itself.

The rod is turned (or purchased with subsequent modification); material - red copper, diameter - with a minimum (relative to the internal hole of the selected resistor) gap, which during assembly is recommended to be filled with silicate office glue (not shown in the figure). Although the glue impairs heat transfer from the heater, it dampens the “copper rod - nichrome spiral” system, protecting the fragile ceramic base of the vitrified resistor from cracks. In addition, the crystallized adhesive layer practically eliminates the occurrence of backlash in the main unit of the soldering iron.

1 - tip (copper rod), 2 - resistor, 3 - asbestos threads, 4 - electrical cord, 5 - ceramic sleeve, 6 - handle (plastic based on thermosetting resins), 7 - rubber sleeve, 8 - metal tube body, 9 - M4 bolt (3 pcs.), 10 - insulation (varnished fabric), 11 - metal casing.

As for the current-carrying wires welded to the resistor terminals, it would seem that they can simply be brought out through a hole in the housing tube. But with a high power soldering iron, it is difficult to avoid melting and burning the insulation near the cord (and there it is not far from short circuit). Therefore, it is better to play it safe by reinforcing the insulation at the point where the wires are connected to the resistor with heat-resistant asbestos thread (followed by impregnation with silicate glue) and installing a ceramic sleeve on the tube body. It would not be superfluous to additionally use an elastic (rubber) bushing to insert the power cord into the handle of the soldering iron.

Last tip. The power of the soldering iron can be quickly changed by adding or reducing the capacitance of the capacitors in the battery. For example, in order to quickly warm up the working rod, it is often enough to connect two more of the same ones in parallel instead of the used 10 μF. The total electrical capacity of the battery will then triple. As the required temperature is reached, the power can be reduced, leaving, say, 20 μF connected (with long-term operation, they are limited even to the previous 10 μF). Moreover, if the mass of the heated rod is substantial, then it happens that they give preference to a soldering iron with a quenching capacitance, the real value of which is less than necessary, and only occasionally (and not for long) they connect a reserve - the entire battery of capacitors.

The phrase “Soldering iron made from a resistor” correlates quite adequately with the phrase “Money out of thin air.” The meaning is the same - to get something from nothing. This is not a crazy attempt to “overthrow” the huge assortment of factory soldering irons that are on the shelves of stores selling electrical products. However, there is for now, but not everywhere, and where there is now may not be later. Life is a changeable thing, especially since even the most expensive one can burn out at such an inopportune moment - so to speak, in the most interesting place. And PEV resistors (wire - enameled - moisture resistant) were, are and will be. So, there is no need to renounce.

Here the housing - the holder is a former connecting plug - the “mother” from the three-program radio “Electronics”.

And here the holder has always been there, but only in the device for welding plastic film. Where it also uses a powerful PEV resistor as a heater, and the product is industrially manufactured.

Resistor calculation

To simplify possible further calculations, I suggest rounding the value of 1594.4 Om to 1600 Om - the calculations will still not be entirely accurate, +/- a couple of watts in power.

P, W D L H d
PEV 3 14 26 28 5.5
PEV 7.5 14 35 28 5.5
PEV 10 14 41 28 5.5
PEV 15 17 45 31 8
PEV 20 17 50 31 8

A soldering iron made from a PEV resistor does not need to be grounded, it will not break through to ground, the main thing is to well insulate its contacts at the point of connection with the power wires. Moreover, it is not necessary to use 220V for heating. For example: if you take a PEV 7.5 resistor with a resistance of 75 Ohms for a soldering iron and apply 12 volts of DC voltage to it, you will get a miniature soldering iron, convenient for soldering SMDs, with a current consumption of 500 mA and a heating element power of just over 7 W. Not everyone has an electrical goods store near their home and not everyone lives in cities, but this is not a reason not to have the necessary soldering iron. Talked about daily matters, Babay.

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Discuss the article HOW TO MAKE A SOLDERING IRON

radioskot.ru

SOLDERING IRON FROM RESISTOR

The 30-watt parameter that appears in the name of the resistor used is the dissipation power at which the PEVZO can maintain its nominal value for a long time (thousands of hours!) without noticeably heating up. Mounted as a heater in a soldering iron (of course, with an inserted copper heat sink rod), this resistor should and can dissipate power many times greater than the rated power.

But the network is 220 V. Consequently, 165 V is the share of the damping resistance, the nominal value of which, according to the law of electrical engineering known from school, should be equal to 300 Ohms. A capacitor (for example, the MBGCH type), designed for an operating voltage of 250-300 V, is the best choice for such a circuit element.

So, the necessary data has been obtained. Now you can proceed directly to making the soldering iron itself.

Resistor based soldering iron:

As for the current-carrying conductors welded to the resistor terminals, it would seem that they can simply be brought out through a hole in the housing tube. But with a high power soldering iron, it is difficult to avoid melting and burning the insulation near the cord (and there is not far from a short circuit). Therefore, it is better to play it safe by reinforcing the insulation at the point where the wires are connected to the resistor with heat-resistant asbestos thread (followed by impregnation with silicate glue) and installing a ceramic sleeve on the tube body. It would not be superfluous to additionally use an elastic (rubber) bushing to insert the power cord into the handle of the soldering iron. Read about a homemade low-voltage soldering iron at the link.

Perhaps the details of manufacturing and calculating resistor soldering irons outlined above may not seem very relevant to anyone, but I think they will be useful not only for novice DIYers.

Noticed a mistake? Select it and press Ctrl+Enter to let us know.

modelist-konstruktor.com

:: SOLDERING IRON FROM RESISTOR::

How to make a soldering iron for small parts using a resistor. As you know, it is more convenient to solder miniature radio components with a small-sized soldering iron - the size of a fountain pen. It must be low voltage and galvanically isolated from the network. This will protect the radio amateur from damage electric shock, will reduce the likelihood of breakdown by static electricity, for example, field effect transistors with insulated shutter. For these purposes, the proposed micro-soldering iron is suitable, which can be made in just a few hours. The power of the soldering iron reaches 15 W with a supply voltage of about 12 V, and the temperature at the end of the tip is 250°C.

The heating element of the soldering iron is ready - it is a metal film resistor of the MON type with a power of 2 W and a nominal resistance of 10 Ohms. The resistor is dipped in acetone or solvent for several minutes to soften the paint coating, and then carefully, trying not to damage the conductive layer, scrape off the paint with a knife. After removing the resistor leads with wire cutters, a 2.5 mm diameter hole is drilled in the center of one of the end contact caps to provide access to the hole in the ceramic base of the resistor.

A heat-protective spring of 10 turns is wound from steel wire onto a rod with a diameter slightly smaller than the diameter of the resistor, and the spring is put on. the end of the resistor in which no holes were drilled, so that 2 turns of it are on the conductive coating. The remaining part of the spring is stretched so that the gap between the turns is about 1 mm, and a loop with a diameter approximately to connect the power conductor is bent at the end.

Another option for attaching the spring is also possible, which may turn out to be no less reliable. In this case, the resistor cap is filed with a file from the end along the edge approximately three-quarters of the circle, the resulting petal is bent and a hole with a diameter of 3 mm is drilled in it. A spring of 5 turns with a diameter of 5 mm is attached to the petal, which is wound in increments of 2 mm from soft steel wire.

The handle of a soldering iron can be, for example, the handle of a jigsaw with a metal ring at the end. Naturally, a homemade handle carved from hardwood will also work. A hole with a diameter of 5 mm is drilled along the axis of the handle for the electrical cord. The protective casing is cut out of sheet steel. The workpiece is bent directly onto the resistor and the resistor cap is secured in the casing with a screw and nut. To attach the petals of the casing to the handle, blind holes are drilled in it and an M3 thread is cut, and then the petals are screwed in with screws with such a thread. A washer is placed under one of the screws and the power cord wire threaded through the hole in the handle is clamped under it; the other cord wire is attached with a short screw and nut to the heat-protective spring. The soldering iron tip can be made from thick copper wire. The end of the tip is inserted into the hole in the resistor housing. For a soldering iron, you can use a resistor with a lower resistance and accordingly reduce the supply voltage so that the power dissipated by the resistor is 10-15 W. MLT or MT will do. True, the length of the MT resistor is longer than MON, and the diameter is smaller, so you will have to change the dimensions of the casing and tip. This homemade soldering iron can be assembled in a couple of hours and performs its functions perfectly.

samodelnie.ru

How to make a soldering iron with your own hands

On the Internet you can find many instructions for making powerful soldering irons from improvised materials. To create some products you need good knowledge of radio engineering, but in most cases a homemade soldering tool can be easily assembled even by a novice electrician. Next, we will talk about how to make a soldering iron with your own hands at home, without having professional skills in working with radio equipment. 3 will be provided to your attention simple instructions, from the simplest to the most complex!

Method No. 1 - Soldering iron from a resistor.

The first and simplest technology for making an electric soldering iron with your own hands is using a resistor. The device will be designed to operate at voltages from 6 to 24 Volts.

In order to make the instrument yourself, you will need the following materials:

Resistor with characteristics: resistance 20 Ohms, power 7 Watts.

Textolite plate for making a comfortable handle.

Two copper rods of different sections. The thicker one is selected strictly according to the internal diameter of the resistor. The second one should be thinner, for the convenience of soldering microcircuits with a small tip.

One bitten off spring ring (will serve as a retainer), a screw and a washer. You can see all the components in the photo below.

To make your own soldering iron from a resistor at home, you must complete the following steps:

1. You need to drill a hole in the end of a thick copper rod and drive the thread under the screw. It is also necessary to cut a groove for the retainer, which in our case is the spring ring.

2. From the second end, drill a hole with a diameter similar to that of a thin rod, which will act as the tip of a mini soldering iron.

3. All elements of the rod must be assembled into one whole, as shown in the photo.

4. The resistor is prepared for attaching the soldering iron tip, which must be inserted and secured at the back with a screw and washer.

5. From a textolite plate you need to make a comfortable handle with your own hands with a seat for a resistor and wire.

6. The power cord must be connected to the heater terminals.

7. The finished homemade soldering iron is twisted and checked.

Please note that with such a portable gun you can easily solder microcircuits and other radio parts.

Method No. 2 - Soldering iron from a ballpoint pen.

Another unusual, but at the same time simple idea for making a soldering iron with your own hands from scrap materials. In this case, we will again need a resistor, but in this case it is no longer a PEV (as in the previous version), but an MLT.

Materials and tools:

Ballpoint pen of the simplest design;
Resistor with characteristics: resistance 10 Ohm, power 0.5 W;
Double-sided textolite;
Copper wire with a diameter of 1 mm;
Steel wire with a diameter of no more than 0.8 mm. It should be noted right away that the steel must take shape and at the same time not be soft, then you will understand why;
Wires for connecting to the network.

Making a soldering iron from a pen at home is quite simple, you just need to follow these steps:

1. Remove the paint layer from the surface of the resistor. If the paint is difficult to remove, connect the product to a regulated power source and heat it up a little.

2. There are 2 wires coming out of the barrel, cut one of them and drill a hole in this place for the copper wire (diameter 1 mm). To prevent the wire from coming into contact with the cup (this must be avoided), make a countersink with a thicker drill, as shown in the photo below. In addition, you need to make a small cut for the current conductor directly on the resistor cup.

3. Bend the steel wire into the shape of a handle with a fastening in the form of a ring, with a diameter similar to that of a drink on a cup.

4. Carefully cut out a board from double-sided PCB with your own hands, exactly the same as shown in the example in the photo.

6. All that remains is to install the thin tip into the seat. To prevent the copper wire from burning through the resistor, you need to make a protective layer of a piece of mica or ceramic between the back wall and the tip.

7. The last thing you need to do is connect the homemade product to a 1 A power supply and a voltage of no more than 15 Volts.

That's the whole technology for creating a homemade mini soldering iron at home. As you can see, there is nothing complicated and all materials can be found at home by disassembling old equipment. This tool can be used to solder SMD components on microcircuits with your own hands.

Method No. 3 - Powerful impulse model.

Well, the last option is suitable for those who are already more or less familiar with radio engineering and know how to read the corresponding diagrams. A master class on making a homemade pulse soldering iron will be provided following the example of this circuit.

The advantage of a more powerful tool is that the tip will heat up within 5 seconds after turning on the power, and the heated rod can easily melt tin. At the same time, it can be made from pulse block lamp power daylight, slightly improving the board at home.

As in previous examples, we will first consider the materials from which you can make a soldering iron with your own hands at home.

Before assembly, you must prepare the following available tools:

Ferrite ring from a pulse converter. The primary winding of the transformer should consist of 100, maximum 120 turns of copper wire with a diameter of 0.5 mm. The secondary winding is represented by one turn of a copper busbar, with a diameter of no more than 3.5 mm.

Copper wire, with a diameter of 1.5 to 2 mm, as a tip.

All you need is to connect the tip to the secondary winding, which, in fact, is already part of it. After this, one of the ballast terminals must be connected to the mains winding of the transformer and that’s it, consider that you have managed to make a good, fast-heating pulse soldering iron at home!

In addition, we recommend watching the video on our social media. networks VKontakte and Odnoklassniki, which show how to easily make a soldering iron stand at home, as well as a temperature controller and homemade soldering irons.

We still recommend using either the first or second method, which is more understandable and easier to manufacture. As for the transformer version, although it is more powerful, it is still not so convenient to use. We hope that these photo instructions were useful for you and finally, we recommend that you watch all the video examples in which the assembly process is discussed in more detail!

Based on materials from samelectrik.ru

delaemvsjosami.ru

A soldering iron is an indispensable device for radio amateurs and home craftsmen. Often there is a need to solder away from a 220 V power outlet and use, for example, a 12-volt car battery for connection. When soldering subminiature devices, mini soldering irons with special characteristics are required. In this regard, many are wondering how to make a soldering iron with their own hands, getting a convenient device and saving money.

Soldering iron for SMD

SMD devices are the chips found in mobile phones, laptops or tablets. The installation of circuit elements is carried out on a site with contacts, where there is a thermal barrier to prevent the spread of heat along the tracks.

Soldering iron requirements for SMD:

The power should not be more than 10 W;
The temperature of the soldering iron should not be higher than that which the microcircuit element can withstand;
If the tip is too cold, then a long soldering procedure can have an even worse effect on the part due to the long time of thermal exposure;
It is necessary to achieve heating of the tip approximately 40°C higher than the temperature at which the solder melts. The main obstacle here is the inertia of the soldering iron.

Material for making the sting

The best tip is nickel-plated copper with additives. This is the most expensive material and finding it for making a soldering iron with your own hands is problematic.

A bronze or brass tip is not suitable for soldering SMD boards because it has high thermal inertia.

A copper tip also has disadvantages: a short service life due to burning, but it can be easily changed. But copper has high thermal conductivity, and better material for working with miniature boards no.

You can make a mini soldering iron with your own hands from an MLT-0.5 resistor. Its tube is thin enough and will not interfere with heating the tip.

What you need to prepare:

case from simple ballpoint pen;
MLT-0.5 with resistance from 5 to 10 Ohms;
piece of textolite 1-3 cm;
steel wire 0.8 mm;
copper wire 1 mm.

Manufacturing stages

Remove paint from the resistor with a sharp object. If it doesn’t clean well, connect it to a power source to warm it up;

At one end of the resistor, cut off the lead and drill a hole into which a piece of copper wire is inserted - the future soldering iron tip. Straighten the second terminal and leave it, it will serve as one current conductor;

Important! The tip should fit into the hole in the ceramic body, but not touch the walls of the side metal cup. To do this, the hole in the cup should be slightly wider than in the body. By the way, only domestic resistors have a housing with holes.

A cut is made along the surface of the same metal cup to lay the second conductor;
The second current conductor is made of steel wire, which is bent so that an open ring is formed in the middle, which fits tightly into the cut made;

In the upper part of the body of a ballpoint pen or some other suitable hollow plastic rod, a board made of double-sided PCB must be installed, which is given the required shape;
A steel wire ring is placed over the cup and soldered to ensure good contact. This negative conductor also serves as a fastening element;
Current conductors are soldered to the upper part of the PCB board on both sides, and conductors are soldered to the lower part, which are threaded into a plastic tube (handle body);
Before placing the tip, a tiny piece of mica must be placed inside so that the copper does not come into contact with the resistor cup located at the other end. The tip can be replaced periodically.

For the supply wire it is good to take MGTF. Its insulation can withstand accidental contact with the heating element. Soldering with such a home-made tool is performed with ordinary solder and flux. A homemade soldering iron is powered from a power supply. You should get 7-10 V at the output, depending on the resistance of the resistor. It’s a good idea to use a power supply where you can regulate the voltage.

Soldering iron made from a resistor

The wirewound resistor is an existing nichrome heater. It is capable of heating up to 250°C when the power is dissipated into the surrounding space. If you install a tip that will remove heat, the resistor can withstand a double power overload for a long time. The tip will heat up to 300°C. You can increase the heating by creating a threefold overload, but then the homemade soldering iron must be turned off periodically (every 1.5 hours).

When calculating a soldering iron, the resistance and power of the resistor are taken into account. The resistor should be of the PEV type, old, but still in production. They are covered with glassy enamel, can withstand repeated overheating, and can only darken.

Important! Resistors of type C5-35B, which cannot be used, are painted on all sides. The paint is not completely removed. When a device made from them heats up, the paint melts and the tip can become stuck forever, without the possibility of replacement.

From the PEV-10 resistor you can construct a soldering iron with a power of 30-40 W. Moreover, if you power it from a 12-volt source, the resistance should be approximately 5 ohms. If the device will operate from a 220 V network, it is necessary to use PEV-20 with a significantly higher resistance. The design of such a soldering iron is similar in principle, but differs in execution.

How to make a mini soldering iron from a resistor, powered by a 12-volt voltage source, can be seen using the example:

It is necessary to prepare the design of the tip so that it is inserted tightly into the ceramic body. A copper rod with a diameter approximately corresponding to the size of the hole in the body is taken and drilled on both sides: for the sting, which will be a slightly smaller rod, and for the bolt for fastening. Both holes must be threaded, as well as on the surface of the tip;

A cut is made on the larger rod, where a ring is put on to fix the entire structure;
Now you need to solder the electrical cord to the terminals of the resistor and make a comfortable handle from insulating material. To protect and strengthen the copper leads of the resistor, you can attach metal clamps to the top of them.

Important! The operating current of the manufactured mini soldering iron should not be higher than 1 A.

These are the two simplest designs of an electric soldering iron. Experienced home craftsmen can complicate them by not using a resistor, but by making the heating element themselves.