Portable homemade USB soldering iron. Convenient and compact DIY soldering iron, powered by USB. Heats up and cools down quickly. Solder wherever you want by connecting a power bank.
Now there are a lot of different homemade soldering irons on the Internet. I decided to do something average, simple in execution and take the best of the homemade products I looked at.
The goal was to make the soldering iron compact, heat up quickly, lightweight and, most importantly, portable.
I decided to abandon the built-in battery to reduce weight and ease of use. The wire doesn't interfere. You can screw in a light bulb for illumination workspace with a separate button.
To make a homemade product we will need:
1. Wood block(I took 7cm x 1.5cm x 1.5cm);
2. Copper wire with a diameter of 1 mm and a length of 9 cm (longer is possible);
3. Nichrome wire 7cm long (taken from an old soldering iron);
4. A bolt or self-tapping screw with a flat head (you can add a washer);
5. Switch;
6. 2 thin wires (I took twisted pair);
7. USB plug with a wire of the length you need;
8. Electrical tape, heat shrink and super glue;
9. Fiberglass.
From the tools:
1. Soldering iron;
2. Pliers;
3. Screwdriver for a bolt or self-tapping screw.
Making a soldering iron
The first step is to prepare the block. Adjust the length so that it is comfortable to hold, grind off the corners.
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We take copper wire with a diameter of 1 mm from 9 cm to 12 cm and bend the ring at one end with pliers so that a bolt or self-tapping screw can fit through.
Let's take it nichrome wire 7 cm long and wound in a spiral (more tightly, but so as not to touch each other) onto the straight end copper wire, leaving workplace for soldering. I took the photo in the article when I didn’t have fiberglass on hand. Keep in mind that there must be insulation, although everything worked fine for me without it.
We screw two copper wiring to the nichrome wire as shown in the photo.
Glue the switch to the block, solder the wires to the switch and wrap the bottom of the block with electrical tape to secure the wires.
We tape the wire to the block with electrical tape and that’s it.
Let's start the soldering iron test.
Sometimes there are situations when the owner simply cannot do without a simple soldering iron. For example, you need multi-core cable for an outlet, or from a burnt-out appliance. At such moments, you have to either borrow a tool or postpone the matter indefinitely. After all, not everyone wants to buy an expensive soldering iron or soldering station if he is not a repairman. However, there is a simple way out of this situation - to assemble a small soldering iron yourself; it is just right for small work. The manufacturing process will not take much time and effort, but you can save some money and get invaluable experience. Next, we will tell you how to make a soldering iron with your own hands at home. You will be offered several designs, and you can choose the one that suits you best.
Idea No. 1 – Use a resistor
First and most simple technology manufacturing electric soldering iron do it yourself - using a powerful resistor. The device will be designed to operate at voltages from 6 to 24 Volts, which will allow it to be powered from various current sources, and even make a portable version powered by car battery. In order to make your own instrument, you will need the following materials:
To make your own soldering iron from a resistor at home, you must complete the following steps:
- You need to drill a hole in the end of a thick copper rod and drive the thread under the screw using a tap. It is also necessary to cut a groove for the retainer, which in our case is the spring ring. This can be done using a triangular file or a hacksaw for metal.
- 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.
- All elements of the rod must be assembled into one whole, as shown in the photo.
- The resistor is prepared for attaching the soldering iron tip, which must be inserted and secured at the back with a screw and washer.
- From a textolite or plywood plate you need to make a comfortable handle with your own hands with a seat for a resistor and wire. To do this, use a jigsaw to cut out two identical halves of the handle and make holes and recesses for screws and nuts.
- A power cord must be connected to the heater terminals. It must be screwed to ensure reliable contact.
- The finished homemade soldering iron is twisted and tested.
We draw your attention to the fact that with such a portable gun you can easily solder microcircuits, even with your own hands. It can work not only from a power supply, but also from a battery. We came across many reviews on the forums where this homemade version was connected from a 12-volt cigarette lighter, it’s also very convenient!
Please note that when first turned on, all soldering irons may smoke and stink for a while. This is normal for any model, as some elements burn out paint coating. This will stop later.
Video instructions for making a simple electrical appliance
Idea No. 2 – Second life for a ballpoint pen
There is another unusual one, but at the same time simple idea how to make a soldering iron with your own hands from scrap materials for soldering small parts or smd components. In this case, it will again be useful to us, but now not SEV (as in the previous version), but MLT, with a power of 0.5 to 2 Watts. 
So, first you must prepare the following materials:
- 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, it can be wound from an old choke or bought single-core at an electrical store copper wire in insulation and carefully remove it with a utility knife
- Steel or copper wire with a diameter of no more than 0.8 mm.
- 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:
- Remove the paint layer from the surface of the resistor. This operation can be carried out using sandpaper, a needle file or a file, or, in extreme cases, a knife. The main thing is not to overdo it, so as not to damage the resistor. If the paint is difficult to remove, connect the product to a regulated power source and heat it up a little.
- 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 wire directly on the resistor cup. A triangular file will help you with this again.
- Bend steel wire in the shape of a handle with a fastening in the form of a ring, with a diameter like a drink on a cup. If you have copper wire, then you need to clamp the cup in it and twist it using pliers so that the contact is reliable, but do not overdo it, otherwise you will wrinkle the body. Remember that the wire must be without varnish insulation.
- Carefully cut out a board from a double-sided PCB with your own hands, exactly the same as shown in the example in the photo. It is not necessary to buy exactly new leaf textolite. You can use a jigsaw to cut out a suitable piece from any unnecessary double-sided board. Or do without it altogether: twist the wire with wires and attach them to the handle using superglue. The main thing you need to pay attention to is that the distance between the heating element and the handle is more than 5 cm, otherwise the plastic may melt.
- Next, you need to assemble a homemade soldering iron from a handle, which should not cause any difficulties.
- All that remains is to install a thin tip in seat. To prevent the copper wire from burning through the resistor, you need to do protective layer from a piece of mica or ceramic between back wall and sting.
- 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 using wires.
That's the whole technology for creating a homemade mini soldering iron at home. As you can see, there is nothing complicated in making this tool, and you can easily cope with it, and all the materials can be found at home by disassembling old equipment or looking for them in bins.
How to make a more complex model of a mini soldering iron at home?
Video review of a device with nichrome wire operating on 12 Volts
Idea #3 – Powerful impulse model
This option will do 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 diagram: 
Advantage of this instrument The point is that the tip heats 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:
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 primary winding of the transformer and all circuit elements must be secured in a reliable housing that will protect you from accidental damage electric shock, since the circuit contains a life-threatening voltage of 220 volts!
The operating principle of this design is that the ballast from the lamp creates AC voltage, which is supplied to the primary winding of the transformer and is reduced to low values, while the current increases many times. One turn, which is essentially the tip of the soldering iron, acts as a resistor through which heat is dissipated. When you press the button, current is supplied to the circuit, and rapid heating occurs; after the button is released, the tip quickly cools, which is very convenient, since you do not need to wait long for the instrument to heat up and cool down.
The main advantage of this mini soldering iron is that it is powered by battery voltage 3.7 V. It is not connected to the network and you can easily take it with you. Of course, its power is not great, but it is quite enough to solder wires or solder some fallen radio element.
So, what do you need to make a mini soldering iron?
- Single-core wire with a core diameter of 2 mm.
- A piece of telescopic antenna.
- Nichrome, wire 0.2 mm. 10 cm long.
- Cambric from fiberglass reinforced.
- Rechargeable battery 3.7 V.
- Battery compartment for this battery.
- A piece of round wood.
- Switch.
- Thin solid wire 0.3-06, diameter (multi-stranded can be unraveled).
Making a mini soldering iron
Let's take a thick single-core wire with a cross-section of 2 mm in diameter. We will remove the insulation using a clerical knife or another method.
Then we take a telescopic antenna from any receiver, joystick or walkie-talkie and disassemble it. We need to find a tube into which our core from the wire will fit tightly. Once the antenna elbow is selected, the remaining parts can be removed.
Using a machine or manually with a file, we sharpen a thick strand of wire into a cone - this will become a soldering tip.
Cut about 1.8 cm with a hacksaw.
We cut off about 4 cm of the tube that we took from the antenna.
We take nichrome wire and measure 10 centimeters, cut off the rest.
Let's take a wire with a diameter of 1.2-1.8 mm. It is only needed for winding the coil; we will not need it later. The material doesn't matter. We wind the nichrome wire, leaving the ends about 1 centimeter.
Then take a thin strand from a copper wire, fold it in half and twist it with wire cutters.
We will thread the nichrome wire into the resulting eye and twist the end around the copper wire. And let's put it aside for now.
Let's take the tube from the antenna and thread the reinforced fiberglass casing inside the tube. If you have a cambric larger diameter– you can make a longitudinal cut and adjust it to the diameter of the tube.
We take everything together and put it together.
We thread a nichrome coil with wire into the cambric so that only a 1 cm long wire sticks out from the outside. From this centimeter we make a turn around the thermal insulation. This will be a thermocouple.
We take our tip and insert it into the tube from the antenna.
On the other hand, we insert our thermoelement all the way.
Take a round piece of wood and cut off about 2-3 cm.
Drill a hole in the center for the soldering element.
We mill a groove from this hole using the same drill, see photo.
Insert the soldering tip with the thermoelement assembly. And bend the tail into the groove.
We drill more holes, but with a smaller diameter and a little further from the center.
We take a thin copper wire and make a loop on the tube and bend it. This will be the second contact.
We insert everything into a round piece of wood.
A soldering iron is an attribute of any radio amateur, from a professional to someone who has just started. Today you can find soldering irons or even soldering stations of any size on sale. But they all have one big drawback - they are quite rough and have a long distance from the end of the tip to the edge of the handle. Such dimensions are convenient when soldering large parts, but when working with small elements, such devices are inconvenient due to the fact that they are very heavy position. Having looked at the diagrams of miniature soldering irons on the Internet, I discovered that many of them have some design flaws: a non-replaceable tip, lack of grounding, and much more. So I decided to try to create more modernized“assistant” for a beginning radio amateur based on several instructions. The features of our future soldering iron include: a short distance from the end of the tip to the edge of the handle (~30–40 mm), handle diameter (~15 mm), the ability to replace the tip and heating elements (spare), ease of manufacture, which will not require any special knowledge.
Homemade miniature low-voltage soldering iron - drawing
An ordinary brush was used as a handle, which was previously sanded and varnished.
To secure the wires in the handle well, I used this homemade unit: I made a thread in a hollow rivet and glued it into the handle. Here you can easily fix the cable using a locking screw.
Next I moved on to making mounts for the heat shield. They were also made from hollow rivets, but with a smaller diameter. An M1.6 thread was created in them and the handles were glued into the holes.
The heating element was taken from an ordinary inexpensive Chinese soldering iron; after some manipulations with the dimensions, it fit our device perfectly.
This element has a power of 7 watts and a length of 6.5 mm. Power supply is provided by an adjustable power supply - from 0...18 Volts. In this case, the heating temperature can reach 280 degrees
An ordinary spring was glued into the back of the pen, which can be borrowed from an ordinary ballpoint pen. This part is necessary to protect the power cable from breaking.
The grounding and power wires are threaded into the cambric. A grounding socket is pressed into the main hole of the plug, which is intended for the cable, and power cables brought out through an additional hole.
As you can see in the picture, the resulting homemade miniature low-voltage soldering iron is barely the same size as an ordinary fountain pen.
On the Aka Kasyan channel, one of the options for making a cordless soldering iron is discussed. A similar soldering iron in online stores costs from 15 to 50 dollars, but we can’t afford it, so it will be cheaper to make it yourself.
Watch from 1:50 minutes
A sting with a heater, how to make it, is shown in the video at the end of the publication.
Li-ion battery standard 18650, the larger the capacity, the better. Charging board for one can lithium battery with protection based on the TP4056 chip. MT3608 boost DC-DC converter module. The case is from a cheap charging 18650 battery, in which the filling of the soldering iron will be assembled. A small switch with a lock, as long as the dimensions are compact. Current is about 3 A and higher.
Where to buy radio components, etc.
You can buy a cordless soldering iron in this Chinese store. You will find the DC-DC converter there by typing in the search: MT3608 2A Max DC-DC Step. Buy a charge board by searching for: Li-Ion Professional 5V Micro USB 1A 18650.
Here is a diagram of a soldering iron. Why everything is so complicated, you will understand later.
Battery soldering iron circuit
Making a soldering iron body
At the very beginning we prepare the body. Lightly processed, removed all unnecessary. This option is convenient because the battery can be changed or replaced if necessary. The case may be different, as long as the battery fits. A pair of 20 milliliter medical syringes is perfect.
The working part of the soldering iron had to be somehow adapted. Fixed it on a terminal made of ebonite. If you work with a soldering iron continuously for ten minutes, the ebonite begins to smell slightly. But the advantage of using this button is that it has a brass bushing with a thread and no additional gadgets are needed to fix the working part.
The body is plastic, and to prevent the ebonite retainer from melting it, I decided to trim the front part of the body and replace it with an implant made of fiberglass. Then I glued all these parts together with Chinese epoxy resin.
DC-DC converter
Why is it needed? The fact is that the heater is designed for an operating voltage of about 9 volts. You can do without a converter. if you use 2 batteries connected in series. But in this case the costs increase, dimensions and the weight of the soldering iron. In addition, it will become problematic to charge the soldering iron from a regular USB connector.
Why didn’t the master make a heater tailored for one can of lithium? ion battery, already explained in the first video.
Let's return to the converter. Quite a popular thing. The maximum output voltage can be about 28 volts at a current of up to 2 A. But real tests have shown that it begins to boil already at inflows of 1 A. If the output rectifier diode and the microcircuit heat up ungodly, but at some point the temperature stops rising, then with the inductor In general, things are bad. After a while it starts to stink. Therefore, I decided to replace it. I had a non-working Chinese 3 A voltage stabilizer module at hand. I simply replaced one inductor with another.
Power inverter
Next, we connect the inverter to a lithium battery, or even better, to a laboratory power source. We apply a voltage of 3.8-4 volts during operation. By rotating the line resistor we achieve 9 volts of output voltage.
I did not change anything on the lithium battery charging board. The charging current is around 1 A, which is quite satisfactory. The only thing I did was replace 2 LED indicator. I used a two-color LED, which brought it to a prominent place. By the way, this board is equipped with protection that will turn off the battery when the latter is discharged below a critical level.
If needed for a long time If you work in the field, you can take a couple of charged batteries with you and quickly replace them if necessary.
It is impossible to mix up the connection if you follow the picture above.
In addition to the charge indicator, I added an LED that lights up when the soldering iron is turned on.
Soldering iron testing
And now that the device is assembled, you can test it. The tip can heat up to a temperature of 350 degrees, but the best thing is that the inverter allows you to regulate the output voltage, and therefore the heating temperature of the tip. So, if you wish, you can output a variable resistor to comfortable spot and get a cordless soldering iron with the ability to adjust the temperature. This is one of the advantages of using an inverter.
Of the minuses. We lose 5-10 percent of power for conversion. This is a minus, given that the instrument is portable and every milliwatt in this case is expensive.
Soldering iron can be used as USB Charger for the 18650 standard this is also a small bonus.
Homemade cordless soldering iron How to make a soldering iron tip