How to Make a Powerful Spot Weld

Do-it-yourself spot welding technology

The spot welding process includes several stages. How to weld metal using spot welding? First, the parts to be joined are aligned in the desired position, placed between the electrodes of the welding machine and pressed against each other. After this, they are heated to a state of plasticity and jointly undergo subsequent plastic deformation.

In industrial conditions, when using automatic equipment, the welding frequency can reach up to 600 points per minute. In order to make high-quality spot welding with your own hands at home, it is necessary to maintain a constant speed of movement of both electrodes and ensure the required amount of pressure and full contact of the parts being joined.

Spot welding - diagram

The parts are heated due to the passage of welding current in the form of a short-term pulse with a duration of 0.010.1 seconds, depending on the welding conditions. This pulse ensures the melting of the metal in the area of ​​action of the electrodes and the formation of a common liquid core of both parts, the diameter of which can range from 4 to 12 mm. After the current pulse ceases, the parts are held under pressure for some time so that the molten core cools and crystallizes.

Heating duration

Monolithic connection

The duration of heating or passage of welding current can vary from thousandths to tens of seconds and depends on the welding conditions and the power of the machine.

When welding parts made of steels prone to hardening and possible cracking (for example, carbon steels), it is recommended to increase the heating time to slow down the subsequent cooling of the metal. Welding of parts made of stainless austenitic steels must be performed, on the contrary, with the shortest possible heating time.

This is done to prevent the danger of heating the outer surface of the connection point to the temperature of structural transformations, which could entail a violation of the high anti-corrosion properties of the outer layers of the metal.

Pressure force

The pressure between the electrodes should ensure reliable contact of the parts at the junction. It depends on the type of metal being welded and the thickness of the parts being connected. The pressure after heating is important, since its appropriate value ensures a fine-grained structure of the metal at the welding site, and the strength of the connection point becomes equal to the strength of the base metal.

Electrodes, technical characteristics and features of use

  • The quality of welding also depends on the correct choice of the diameter of the copper electrode. The diameter of the connection point must exceed the thickness of the thinnest element of the welded joint by 2 - 3 times.
  • By pressing the parts at the moment of passage of the welding pulse, the formation of a special sealing belt near the molten core is ensured, preventing the splashing of molten material from the welding zone. As a result, no additional protection measures are required at the connection point.
  • To improve the crystallization of the molten metal, the electrodes must be opened with a slight delay after the welding pulse has passed.
  • To obtain a high-quality and reliable weld, the surfaces to be joined must first be prepared, in particular, cleaned of rust.
  • The gap between the connection points should provide a reduction in current shunting through adjacent points. For example, for welding two (three) parts with a thickness of 1 to 8 mm each, the distance between the connection points varies accordingly from 15 (20) to 60 (100) mm.

Quality of materials

  • Electrodes used for spot welding must provide strength in the operating temperature range, high thermal and electrical conductivity, and ease of machining. These requirements are met by special bronzes containing cobalt or cadmium, cold-rolled electrolytic copper and copper alloys containing chromium, as well as a tungsten-based alloy.
  • In terms of electrical and thermal conductivity, copper is significantly superior to bronze and alloys, but 5–7 times worse than them in terms of wear resistance. Therefore, the best alloy for the manufacture of electrodes is considered to be an alloy of the EV type, which is almost pure copper with the addition of 0.7% chromium and 0.4% zinc. In order to reduce wear of the electrodes during operation, it is recommended to use intensive cooling with water.

Application area

At home, do-it-yourself spot welding is most often used when repairing household appliances, various works with aluminum, cables, or repairing small kitchen utensils.
In industry, spot welding is used for welding sheet blanks made of steels of various grades, non-ferrous metals and alloys of various thicknesses, intersecting rods, profile blanks (angles, channels, tees, etc.).

Advantages and disadvantages of spot welding

Like any technological process, electric spot welding has its advantages and disadvantages. The first include, first of all, the mechanical strength of spot welds and high efficiency, as well as the possibility of automating welding work. A significant disadvantage is the inability to ensure the tightness of welding seams.

Using a homemade welding machine

For welding work at home, you can make a spot welding machine assembled by yourself. Homemade welders can have a wide variety of configurations - from small portable ones to quite large ones. At home, desktop versions are usually used, which can be used for welding ferrous and non-ferrous metals.

Base of the device

The main structural part of one of these welding machines is the base transformer. To do this, it is best to use a mass-produced device, for example, OSM-1. The primary winding of the transformer can be left unchanged, but it must contain at least 200 turns. The secondary winding must be replaced with a more powerful one, using wire PEV 2/1.9 or PV Z - 50. Transformer OSM - 1

Adjusting the current value in the device is not necessary. During the welding process, it is necessary to navigate by the duration of heating and control it visually by color. To make electrode holders, you can use a duralumin rod with a diameter of 30 mm.

Electrode design

The lower electrode must be made motionless and isolated from the cheeks and mounting bolts with adhesive tape and washers. To secure the electrodes in the holders, you can use two bolts or brass washers.

Then you can take some springs, say from a folding bed. The holders with electrodes should be moved back to their original position by a spring. The spot welding machine is connected to the network using a circuit breaker rated for a current of at least 20 A.

Device control

The device itself can be controlled by a magnetic starter, which can be turned on by pressing a pedal. The transformer housing and its secondary winding must be grounded. The parts to be connected must be clamped between the electrodes. The current flowing between them heats up the metal, after which the electricity is turned off, the compression force of the electrodes increases and, as a result, a welded joint is formed.

DIY spot welding rollers

1. on the use of the GYSPOT 3502 spot welding machine, designed for removing dents using an inertial hammer, welding rivets, studs, nails, dowels, washers and bolts, removing pits and upsetting surfaces using a carbon electrode:

2. on the use of the double-sided spot welding machine GYSPOT 32D-C for repairing surfaces and connecting the car body:

3. Do-it-yourself capacitor welding with automatic supply of hardware:


How to make spot welding: general information and technology, making a welding machine with your own hands

There are often situations in which it is necessary to connect metal products or repair various structures. To deal with this, you need to know how to make spot welding yourself. The apparatus for carrying it out can be assembled independently at home. This will greatly simplify the entire process and save you from large financial costs.

Homemade spot welding is a rather difficult undertaking that requires special equipment and skills for such work. However, with the right approach, you can significantly simplify the process and get the job done in the shortest possible time.

Main advantages

This method of joining metal parts has many advantages. All of them make spot welding one of the most commonly used. Among the positive aspects it is worth highlighting the following:

  • seam strength;
  • low cost of the process;
  • reducing time costs;
  • simplicity of equipment;
  • the ability to perform in a home workshop;
  • automation in enterprises.

Among the many advantages, there is one drawback. Experts consider this type of connection to be leaky.

Brief technology

Welding of any product occurs according to the same principle. At the same time, it is important to carefully carry out all operations and not miss even the most insignificant nuance. Only in this case can you achieve an ideal seam and its strength.

The whole technology consists of several stages:

  1. The parts to be connected are aligned in the desired position and securely fixed.
  2. They are then placed between the electrodes of the welding machine and compressed tightly.
  3. After this, the workpieces are heated. This must be done until the material becomes plastic and easily deformable.
  4. The device transmits a short-term impulse, due to which the metal melts at the points of contact with the electrodes.
  5. As soon as the current stops, the molten material solidifies and reliably holds the parts together.

Preparatory activities

The basis for the successful completion of any type of work is considered to be proper preparation. It allows you to take everything you need to carry out a smooth process. To successfully carry out contact welding from a welding machine with your own hands, you need to choose the right electrodes and all the necessary tools.

Selecting Electrodes

The main attribute of contact welding is the electrode. With its help, the entire process is carried out, so it is very important to buy the best option for a specific job.

The electrode performs the function of supplying current to the parts being welded and compressing the metal. As a rule, it is made from alloys with high thermal conductivity. The tip is exposed to the greatest impact. It heats up to enormous temperatures and wears out very quickly. Because of this, it is necessary to constantly sharpen it during work. The most commonly used tip shape is a cone.

As a rule, electrodes are quite expensive, so it is very important to extend their service life as much as possible. To do this, you must comply with the following conditions:

  1. To weld products from a particular material, it is necessary to select the optimal types of electrodes for it.
  2. Do not use fine tips for heavy welding.
  3. Use a water jacket.
  4. Observe the storage conditions for the electrodes and avoid their mechanical damage.

Experts do not recommend filing them, as this can lead to cracks and unevenness. Due to such defects, the welding process will become more complicated, and the resulting seam will be of poor quality.

Materials and tools

To carry out contact welding with your own hands, you need to make the appropriate unit. It is done using a certain set of tools and a minimum amount of materials available to everyone. While working on the device you will need:

  • electric drill;
  • Bulgarian;
  • milling cutter;
  • hacksaw for metal;
  • file;
  • soldering iron;
  • hammer;
  • chisel;
  • sharp knife;
  • screwdriver;
  • metal scissors;
  • metal ruler;
  • calipers;
  • spanners.

Equipment manufacturing

After all preparatory activities have been completed, you can begin to work on the device. Its assembly is carried out in several stages and can take a significant period of time.


How to make spot (resistance) welding with remote pliers

Previously, we already looked at how to make spot welding from a microwave transformer. However, you can only work with such a device permanently. But what should you do if there is a need to use suspended spot welding in hard-to-reach places, for example, when performing body work (welding car sills).

And in order to be able to perform such operations, external pliers will help us. But there is one nuance here: the longer the wires from the transformer, the more the power of the spot welding machine drops. Therefore, it is initially necessary to manufacture a device that is much more powerful. Of course, one transformer from a microwave is not enough here. You will need two transformers from the microwave, or you can use any other large transformer.

Watch the video

  • How to make spot welding
  • Secondary winding
  • Assembly

How to make spot welding

In this case, for the production of spot welding, a TBS3-0.63 transformer (analogous to OSM1-0.63), whose power is 630VA, was used.

The primary winding is designed for 380V, and the secondary for 220V with taps for 22V and 5V. But the best thing is that this tape magnetic circuit is very easy to disassemble by unscrewing only one tightening screw.

Since the primary transformer is designed for 380V, and the home network is designed for 220V, it is necessary to completely remove all windings. It is necessary to unwind carefully, since we will still need this wire to wind the primary winding. When removing a 220V winding, I recommend calculating how many turns it contains, so as not to resort to calculations using the formula:

W=(30(35)/ S)*UW - number of turns of the primary winding, S cross section of the core cm sq, 30-35 conditional coefficient

U - voltage

The winding was made in 2 wires (so that the winding would heat up less), which was obtained when removing the primary and secondary windings. We wind it turn to turn, separating the layers with a dielectric (lacquer cloth). In total there were 264 turns, which were laid in 8 layers. And there is still a 14mm gap left for winding the secondary winding.

Measuring the current at idle showed a consumption of 0.36A (permissible XX current up to 2 amperes).

Secondary winding

As for the secondary winding, if the clamps were stationary, then 4 turns of wire with a cross-section of 100 sq. mm would be enough. But in this case, since the pliers are remote, the length of the wire from the transformer to the electrodes was 1.7 m. And the longer the wires, the more the power of the device drops.

Unfortunately, I do not know whether the power drop is due to a decrease in secondary current due to thin wires (relative to length) or due to voltage drop during welding. Therefore, I decided to wind 6 turns of 50 sq. mm wire to compensate for the voltage drop during welding.

The pliers were made from a 1/2″ water pipe 50cm long, through which the wires were pulled and bolted directly into the electrodes. Holes were drilled in the electrodes to a depth of 50mm to ensure the largest area of ​​contact between the wire and the electrode. The junction of the pincers is carefully isolated from each other with textolite washers.

The work with the transformer is completed. Now you can start making the body. There was a sheet of 2mm thickness available. It is quite difficult to bend a box made of such thick metal on a sheet bending machine, so grooves were cut in places where the bends were made using a grinder. While the edges are not bent, it is advisable to immediately drill and cut all the necessary holes (fans, sealed leads, etc.).

If there are cuts, bending a thick metal box evenly is not difficult.

Ventilation holes must be provided in the lid. You can simply drill a lot of holes, but this is time-consuming and ugly. Therefore, metal ventilation grilles were purchased, and holes were cut in the lid for these grilles.


After painting the body, we begin assembly. We install sealed leads (so that the wires do not rub against the edges of the case), and 12V computer fans.

Since the hole for the fans was cut rectangular, standard grilles for the cooler would not look nice. And for aesthetic reasons, a rectangular ventilation grill measuring 160x80mm was installed. Unfortunately, it was not possible to find a metal one of this size, so I had to settle for a plastic one.

Since there was a desire to assemble a compact spot welding machine, the distance from the transformer to the sides of the housing is only a couple of centimeters.

All electronics: a 12V power supply, a timer and a triac on the radiator were located on the side ties of the case. The radiator is positioned so that it is level with the ventilation hole of the cover.

To protect against overheating, two thermal fuses were installed. One thermal fuse is installed between the windings in the transformer. And the second is attached to the triac.

The front panel contains a device power button, a timer, and LEDs indicating the network is turned on and the transformer is operating. Since the current consumption of the device during welding is more than 20A, it should be noted that in this case the button only turns off the 12V power supply. And since the triac does not work without power, the device can be considered de-energized.

But this is not an entirely correct solution, since in the event of a breakdown of the triac (voltage surges, factory defects, etc.), the transformer will turn on, and if the clamps are closed, overheating and ignition will occur. Therefore, in order to prevent such an outcome, it is necessary to install a 25A circuit breaker as a switch, or after completing work, disconnect the device from the outlet, or do not leave the clamps closed.

As for the timer, it is not at all necessary to install it, since it is mostly necessary for welding thin wire. And sheet metal can be completely welded without a timer.

The transformer control circuit, without a timer, is quite simple and does not contain many elements.

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For welding parts made of thick metal, a timer is, in principle, not needed. But if you have to work with thin metal or for welding wire, then a timer with power adjustment is simply necessary.

Since it is not so convenient to work with such large pliers, an additional handle was attached, which will allow you to work with pliers with only one hand (CRAB clamp). A control button was located on this handle, and a heat tube was placed on the handle itself.

After painting, we insert the wires into the pliers pipe and install them into the electrodes. At the ends of the pipes, pieces of 3/4″ pipe are installed to strengthen the threads, so that the threads are not stripped by tightly screwing the bolt.

It is worth noting that the rods are made of metal, so you do not need to use a release spring. And it is worth paying special attention to the isolation of the pincers so that the CRAB mechanism does not close the two halves of the pincers together.

This is what a spot welding machine looks like after painting. Since the device weighs 16 kg, it is necessary to install a carrying handle on the lid.

Due to the fact that long wires, thick metal cannot be welded, but with a package of 4 galvanized plates 0.5 mm thick or three ferrous metal plates 1 mm thick, it copes quite well. You can see how the device copes by watching the video after 10 minutes.


How to make spot welding with your own hands - Machine tools, welding, metalworking

Home plumbing work is part of the life of a business person. One of the most popular home devices is spot welding. It assumes the presence of a factory or homemade welding device. It is not difficult to create a similar device that will be used for spot welding with your own hands; you only need desire and some available tools.

Features and principle of spot welding

Let's start studying the question of how to make spot welding with our own hands with the principle of operation.

Today, spot welding is in demand not only in everyday life, but also in production, as it can solve even the most difficult tasks. In industry, as a rule, devices operating in automatic mode are used; in domestic conditions, a semi-automatic welding machine is used for spot welding.

Spot resistance welding in production is necessary to weld sheet blanks from ferrous and non-ferrous metals. It is used to weld products from profiles of different thicknesses and configurations, as well as intersecting metal workpieces. Under some conditions, it is possible to achieve a high-speed operating mode of up to 600 points per minute.

Many people are interested in the question of how to make spot welding at home? In the home environment, spot welding is used to repair household utensils and, if necessary, to weld electrical wires.

The spot welding procedure includes several stages:

  • the workpieces are combined in the required position;
  • fasten the parts directly between the clamping electrodes of the installation;
  • the surfaces are heated, during which the parts are deformed and they bond with each other.

There is another point connection technology - laser welding. It is capable of performing tasks involving high precision work and extreme soldering strength.

It turns out that the principle of spot welding is the excessive heating of working metal surfaces, which results in their fusion and a single structural new formation.

The main role in the welding process is played by the impulse response of the current, which creates the necessary heating of the metal area. An equally important characteristic is the exposure time and the holding force of the parts. Thanks to these parameters, the metal structure crystallizes.

The main advantages of electric contact welding from a welding machine are:

  • profitability of use;
  • strong seam;
  • simplicity of equipment;
  • homemade spot welding can be created at home;
  • possibility of automation in an enterprise environment.

The only flaw in the point connection of parts is considered to be a leaky connection.

The main requirements for welding equipment are:

  • the ability to change the process time;
  • creating pressure in the working area, reaching the limit at the end of the heating process;
  • the presence of electrodes with high energy and heat conductivity.

For household use, electrolytic copper and its mixture of EV grade are suitable. It is worth noting that the area of ​​the contacted area of ​​the electrode must exceed the joint (seam) to be welded by 2.5 times.

Assembling a welding machine yourself

To spot weld parts, it is necessary to create appropriate equipment.

A homemade do-it-yourself spot welding installation can have any shape - from portable varieties to large-sized models.

In practice, desktop versions are usually used, used for joining various metals. Before you create spot welding from an inverter, you should familiarize yourself with the materials that will be needed during manufacture.

  • energy converter, that is, a transformer;
  • electrical cable with insulation with a cross-section of 10 mm;
  • copper electrodes;
  • breaker;
  • tips;
  • bolts;
  • available tools and materials for creating a frame base or welding pliers (blocks of wood, recycled materials, plywood).

1 — modified OSM-1.0 transformer; 2 — conductor (duralumin rod with a diameter of 30, L300, 2 pcs.); 3 — liner (steel rod with a diameter of 10, L30, 2 pcs.); 4 — electrode (copper rod with a diameter of 12, L50, 2 pcs.); 5 — brass washer (2 pcs.); 6.12 — M6 screws; 7 handle; 8 - eccentric; 9 — cheek (2 pcs.

); 10 - spring; 11 — output of half of the secondary winding (4 pcs.); 13 — textolite bushing (with a groove for the end loop of the spring); 14 — M8 bolt (6 pcs.); 15 — textolite washer (4 pcs.); 16 — insulating coating (varnished fabric or protective adhesive tape on a fabric basis, 2 pcs.); 17 — transformer casing.

Installation diagrams

The main types of welding device assembly schemes are simple projects with a minimum amount of required materials. It is worth noting that the manufactured equipment will not be powerful, that is, this spot welding scheme is intended only for domestic use. Its purpose is to weld small sheets of iron and electrical wires.

To understand how to do resistance welding, remember the school curriculum, namely the physical rule “Joule-Lenz Law”: when electricity passes through a conductor, the amount of thermal energy created in it is directly proportional to the resistance of the conductor, the time of exposure and the square of the electric current. Conclusion, if the current was initially large (for example, 1000 A), then with a weak connection and small wires more energy will be consumed (several thousand times) than with a lower electric current (10 A). That is, the quality of the assembled electrical circuit plays an important role.

The formation of an electrical pulse between two sections of metal products is considered a basic part of the operation of a welding installation. This will require a small energy converter. The product to be welded must be connected to the lower winding of the device, and the metal electrode to the secondary.

It is worth noting that it is unacceptable to directly combine the converter with the power source. For this purpose, a bridge with an electronic switch (thyristor) is provided in the electrical circuit. To create the required pulse, the device must be supplied with auxiliary power, which includes an energy rectification bridge and a transformer. The electric current will be concentrated in a capacitor, whose role is to generate a pulse.

In order for a home-made resistance welding machine to work, you need to press the “pulse button” on the handle of the gun to open the capacitor-resistor circuit diagram.

As a result of these manipulations, a discharge will occur through the metal rod. To reinforce the theoretical material, it is recommended to watch the training video, which explains in detail about spot welding.

This allows you to visually understand how this is all done correctly.

Homemade device from a microwave oven

Since it is not always possible to allocate an extra amount of money for spot welding machines, you can make it yourself. This will require a fairly powerful microwave oven.

Transformer assembly

You only need one part from the microwave - a high-voltage transformer for spot welding. This part requires only a core (magnetistor) and a primary (lower) winding. To remove unnecessary areas, you can use a hammer, grinder or hacksaw.

After removing the transformer secondary winding, it is necessary to create a homemade transformer for resistance welding. To do this, you should use a copper cable with a diameter equal to the opening of the transformer. It is necessary to make two turns.

In order to connect the two parts of the core you will need epoxy resin.

Next, you should test the output voltage from the device. The optimal value is considered to be 2 volts, and the current strength is about 850 amperes.

If wood is used instead of plastic, then first you should perform several preparatory operations, namely sanding, impregnation and varnishing. To create a homemade working machine for spot welding with your own hands, you will need:

  • welding installation power cable;
  • Door knob;
  • switch;
  • copper holders;
  • large diameter electrical wire;
  • consumables (screws, nails).

After the body section has dried, it is necessary to assemble the installation and combine all the associated parts. After this, the copper wire is cut into 2 parts, each of which is approximately 25 mm. These elements will perform the function of electrodes.

To fix them, just use a standard screwdriver. Then you need to install the system key; a thick electrical cable will prevent it from slipping out.

To fix the transformer to the structure body, you can use self-tapping screws, but do not forget about grounding one of the terminals.

To increase the safety of using the welding device, it is recommended to install an auxiliary switch. Small nails and other fasteners are also used to secure the working arms. Contact metal rods are attached to the end parts of the handles. To raise the upper handle, a standard polymer is used - rubber.

Creation of electrodes

Elements used for do-it-yourself spot welding must meet certain requirements, namely resistance to operating temperatures, good electrical conductivity and ease of machining.

Copper wires with a cross-section of 15 mm or more are perfect for this. The basic principle is that the cross-section of the electrode should not be less than the diameter of the wire. If you don’t mind, you can use the tips of 2 soldering irons, which will definitely last a long time.


The do-it-yourself resistance welding has a simple device. There are only two control systems - a switch and a handle. The spot welding switch is fixed in the primary winding circuit.

This is necessary because there is more current in the secondary winding, and the switching system will create additional resistance. The switch is installed on the lever, so it will be more convenient to work.

That is, you can turn on the electricity with one hand, and hold the materials being welded with the other.

It is worth noting that turning the welding current on and off must be done only with the electrodes compressed, because otherwise a spark will appear, leading to their burning. It is also recommended to use a fan to cool the device.

If such a cooling system is not available, then the temperature of the energy converter, metal electrodes, electrical wires should be constantly monitored and additional breaks should be created to prevent overheating.

Today, purchasing a welding machine for spot welding is not a problem if you have the money. Any specialized store will offer a range of installations for point joining of parts, with different capacities and manufacturers.

But for home craftsmen it is not always possible to select the required parameters, so making a spot welding machine with your own hands will be the optimal solution. All necessary supplies can be borrowed and found at home.

A do-it-yourself spot welding installation does not fail and works perfectly, thereby providing the required minor repairs to metal products.


What are electrodes for spot welding made of?

Welding plays an important role in technical processes. One of its types, spot welding, is the joining of parts together at one or more points. A spot welding machine can significantly reduce the final cost and reduce production time, especially if made by yourself.

Welding Strength

The strength of the weld is affected by the size and material of the area. And it is affected by:

  • Electrode size.
  • Contact area.
  • Surface condition.
  • Exposure time and current magnitude.
  • The size of the surface with which the electrode was in contact.

Precision welding has its niche application - connecting parts to each other from 0.002 microns to 20 mm. During the process, the current value is measured in hundreds of amperes, and the resistance of the surface and electrodes is minimal.

Advantages of spot welding:

  • High strength welding seam.
  • Automation of work.
  • Economical.

The process is used both at home and in industry . It is used to weld the following materials:

  • Sheet metal.
  • Products made of non-ferrous alloys and steel.
  • Bent and sectional profiles.

In everyday life, tools, household utensils, and kitchen equipment are repaired using spot welding. The process consists of combining parts in a certain position. They are fixed to each other and the electrodes with the help of an electric current, and the surfaces are heated before welding. The main thing is to accurately fix the part in the desired position and hold it during the welding process. The thermal impulse melts the metal in the contact zone, connecting the two surfaces into one.

Types of spot welding machines

The simplest spot welding machine is controlled manually; the welding current and operating time are set each time. Requires experience with a specific device. Quite a simple design, easy to make with your own hands.

The devices come in three varieties:

  1. Automatic systems allow even non-specialists to perform high-quality welding. This reduces the number of defective products and labor costs.
  2. Mechanical drives are the most popular version of a spot welding machine; they are widely used in many industries; making them yourself is not difficult.
  3. Hydraulic and pneumatic clamping devices are used in stationary machines in industrial facilities.

Portable devices are not inferior in their characteristics to stationary ones. The welding machine, made in the form of hand pliers, is capable of joining metal 5 mm thick. And with the help of a manual locking drive, a force of 150 kg is achieved. Ease of use, high quality welds, low price, distinguishes this type of device from its competitors.

Inventory devices are small in size, multifunctional, and easily connected to a household network. And even the high price does not reduce their popularity.

DIY spot welding machine

The simplest one to make at home is a spot welding machine, in which the current strength is not adjustable. And the process is controlled by changing the duration of the electrical pulse; for this, a switch or time relay is used.

The welding machine operates on the principles of the Lenz-Juol law : electric current passing through a conductor emits heat, which is directly equal to the square of the current, time and resistance of the conductor. This means that at a current of 1000 A, on thin wires and poorly made connections, the losses will be 10,000 times greater than at 10 A.


The main element of any equipment for spot welding is power, with an increased transformation effect (to obtain a normal welding current). It can be taken in a powerful microwave (from 1 kW and above) , it powers the magnetron. Convenient for its availability and good characteristics. The transformer’s performance is sufficient for spot welding 1 mm steel sheets. To obtain more power, use 2 or more parts.

To operate a magnetron in a microwave oven, you need an increased voltage of 4000 V. Therefore, an increased transformer is used. It has fewer turns on the primary winding than on the secondary, but the thickness of the wire is greater.

The performance of such transformers is up to 2000 V (in a microwave it doubles before being fed to the magnetron), you should not connect them to the network and measure the output characteristics. From this part we need a primary winding (which has a thicker wire and fewer turns) and a magnetic circuit.

The wires are cut with a chisel or a hacksaw (if it is welded and not glued), or they are picked out and drilled out (if the winding is packed very tightly, when knocking it out will destroy everything). When removing the secondary winding wires, try to act carefully so as not to damage the primary winding . There are also shunts in the transformer that limit the current; they also need to be cut off.

After carefully removing the necessary elements, the secondary winding of the transformer is updated. To achieve current ratings of 1000 A, you need to use a copper cable with a cross-sectional thickness of 100 mm² or more. This can be a bundle or stranded wire. If the external insulation prevents you from obtaining the required number of turns, then it is removed and replaced with fabric insulating tape. The wires should be as short as possible to avoid unnecessary resistance.

No more than 3 turns are made. You will get 2 V, this is enough for home needs. But if you need more current, then make more turns, so you will increase the power ratings . Multiple transformers can also be used. This is a good option when you have 2 identical ones, but their characteristics individually are not enough to weld metal of the required thickness.

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For example, if you have 2 transformers with a power of 0.5 kW, with an input voltage of 220 V, with a rated current of 250 A and an output voltage of 2V. By connecting the terminals of the secondary and primary windings, we get a device in which the rated voltage is 2 V, the output current is 500 A (the welding current will also double).

When creating a device, electrodes must be used in the secondary circuits of the device. That is, when using 0.5 kW transformers , they are connected together with wires with a diameter of 1 cm, and the ends are connected to the electrode. If you make a mistake when connecting the terminals of the secondary and primary windings, this will lead to a short circuit.

When you use two powerful transformers and you need to increase the voltage, but the size of the magnetron window does not allow you to add the required number of turns of wire, for this the secondary windings are connected in series. It is necessary to coordinate the direction of the turns, otherwise you can get antiphase, which will lead to an output voltage equal to zero (to correctly understand this point, conduct an experiment with thin leads).

The terminals of the same name are marked on the transformers, but if your device does not have one, you can check it. to the primary windings of the transformers , and a voltmeter is connected to the secondary windings. There can be two results: the device shows voltage or not.

The first case indicates that the circuits of the primary and secondary windings are connected together by opposite terminals (the voltage on the primary winding is equal to half the input, which is converted in the secondary winding, where it is summed up and gives a double value). The zero value of the voltmeter shows that the voltage values ​​on the secondary windings are opposite, which means that one of the pairs of windings is connected by the same terminal.

To increase the performance of your spot welding machine, you need to connect several transformers, but they should not exceed the network performance, otherwise the total voltage will drop when using it. Limit yourself to 1000–2000 A; for domestic conditions, this current strength is sufficient.


Copper rods are used as electrodes. The greater the thickness, the better, but its diameter should not be less than that of the wire. If you have a low-power device, then soldering iron tips will do.

Electrodes require periodic pumping, as over time they lose their shape and become unusable. The shorter the length of the wire going from the electrode to the transformer, the better. The number of connections should be minimal; they also waste power. Ideally, copper tips are attached to the ends, to which the electrodes are connected. Oxidation occurs at the point of contact of copper, to avoid this they are soldered together. This connection is easier to clean.

When using crimping, the fastening area is much smaller, which increases losses.


The device is controlled by a switch or lever. The electrodes must be fastened with such force as to ensure normal welding. The thicker the sheet of metal, the higher the indicator. On industrial devices it reaches 100 kg . Make the control lever long and strong, and the device itself more massive, with the possibility of stationary mounting. Additional force can be added when spot welding using a screw clamp.

The switch is connected to the primary winding circuit, otherwise it will add resistance, and its contacts will melt during operation.

If you use a lever clamp mechanism, then mount the shutdown button on it. It is very convenient to press the lever with one hand and control the work. The second hand controls the welding of parts.


The device must be turned on and off when the electrodes are compressed, otherwise the electrodes will spark and burn. Forced ventilation will greatly facilitate operation , otherwise you will have to monitor the temperature of the transformer, electrodes, conductors and take frequent breaks. In the meantime, while you empirically find the temperature conditions of the elements, something may burn out irrevocably.

To carry out spot welding efficiently, you need experience in bringing together two surfaces of a material, welding with a current pulse, and determining the readiness process by color and appearance.

  What are graphite electrodes?

When carrying out spot welding with your own hands, follow safety precautions; if sparks and molten metal occur, stop work immediately. Operating a faulty device is very dangerous.

  • Alexander Romanovich Chernyshov


How to make spot welding with your own hands?

How [do-it-yourself spot welding] is carried out, what kind of apparatus is used, is it possible to do it yourself - below we will try to answer all these questions.

Technological process

Spot welding is used not only in production, but also at home.

On an industrial scale, the choice falls on this type of welding when it is necessary to join alloys of non-ferrous metals, steel of various grades, when sheets have different thicknesses, when creating profile workpieces, for example, angles, etc.

At home, spot welding has found its application in the repair of household appliances, batteries, and cables.

To reduce the cost of replacing system batteries, this machine can be used to weld batteries for laptops, screwdrivers and other mobile devices.

Welding of batteries occurs using conventional technology.

The welding process itself consists of heating a metal object to a state of plasticity, after which it is deformed, that is, connected.

To create a better quality seam, it is necessary to ensure consistency of the process, that is, constantly maintain the same speed of processing the object, and monitor the pressure.

These requirements apply more to manual welding, since in enterprises this process is performed automatically.

Heating of metal objects occurs by passing an electric current, which generates heat on the surface.

In the place where the electrode came into contact with the surface, a liquid core begins to appear, formed from the melting of two parts.

When the current stops flowing (0.01-0.1 sec), then the core begins to solidify, thereby allowing both parts of the parts to be held.

To compress a metal sheet, pliers are used, which are divided into manual and suspended.

Hand pliers help generate current, which is subsequently supplied to the electrodes that clamp the workpiece. Hanging pliers are used in industry and are characterized by high productivity.

Resistance spot welding has a number of advantages:

  • Speed ​​of work;
  • Safety of work is achieved due to low voltage;
  • The strength of the connection is ensured, but, unfortunately, not tightness;
  • You can make a welding machine yourself at home.

Process Features

Resistance spot welding is a simple process: current passes through the spot connection, generating heat.

At the same time, the condition of the contacts affects the quality of welding; any roughness or oxide can have an adverse effect.

IMPORTANT TO KNOW: Selecting and designing a hair dryer for soldering microcircuits

See the video for the spot welding process.

When welding, it is necessary to take into account such properties of metals as thermal conductivity, resistance and melting point, since they are different, for example, iron will melt at a temperature of 1300 degrees Celsius, copper - 680, aluminum - 435, zinc - 1115, etc.

Electrodes also have certain requirements:

  • High rates of heat and electrical conductivity;
  • Strength;
  • Mechanical processing should be easy.

To extend the life of the electrodes, it is recommended to cool them with water during operation.

The quality of the weld seam also depends on the diameter of the electrodes; it determines the current density.

In order to visually correctly select the diameter of the electrode for the sheet being processed, it is necessary to multiply its thickness by two.

Resistance spot welding can be carried out not only on an industrial scale, but also at home.

To avoid having to use bulky equipment at home, manufacturers have released a compact device suitable for minor repairs, for example, household appliances, batteries or a car.

The device is called a spotter. It has two terminals, one of which is attached directly to the object, and the second to the electrode.

In this case, pliers are not needed. To ensure a better working process, it is advisable to select the power source so that it is located as close as possible to the welding site.

Despite the fact that the spotter is more of a hand-held device, it is quite functional.

The simplest devices using single-phase current are reliable and simple, but metal sheets thicker than 0.8 mm cannot be connected.

More complex and powerful models use a transformer; it should be noted that they are more expensive. But the most expensive spotter is the inverter one.

In everyday life, you can get by with a cheaper device made by yourself.

Spot welding is characterized by the strength of the seam, which sometimes has to be removed by drilling. The drill is usually used when repairing a car.

It should be noted that there is a special drill for drilling spot welds. It is better to buy a drill rather than use some drill that you think is suitable. The price for such a drill is low. This work must be carried out carefully so that the body can be repaired in the future, rather than ordering a new one.

Diagram of a homemade welding machine

For everyday needs, there is no reason to buy a welding machine, especially since you can make it yourself.

IMPORTANT TO KNOW: Lessons on semi-automatic welding for beginners

The dimensions of such a device will directly depend on the needs. It is more convenient to assemble a medium-sized device. Below is a diagram of a spot welding machine.

1 — modified OSM-1.0 transformer; 2 — conductor (duralumin rod with a diameter of 30, L300, 2 pcs.); 3 — liner (steel rod with a diameter of 10, L30, 2 pcs.); 4 — electrode (copper rod with a diameter of 12, L50, 2 pcs.); 5 — brass washer (2 pcs.); 6.12 — M6 screws; 7 handle; 8 - eccentric; 9 — cheek (2 pcs.

); 10 - spring; 11 — output of half of the secondary winding (4 pcs.); 13 — textolite bushing (with a groove for the end loop of the spring); 14 — M8 bolt (6 pcs.); 15 — textolite washer (4 pcs.); 16 — insulating coating (varnished fabric or protective adhesive tape on a fabric basis, 2 pcs.); 17 — transformer casing.

The operation of the welding machine is based on the physical law of Lenz-Joule.

The meaning of the law is that the conductor begins to generate heat by passing electric current through itself, in an amount proportional to the resistance of the conductor material, the square value of the current and the time it takes for the current to “pass.”

Wires are selected taking into account this law.

Since resistance spot welding occurs due to an electric pulse, to create the device you will need a transformer, which is not recommended to be connected directly to the power source.

A rectifier bridge with a thyristor is required for proper connection.

The circuit of a homemade device involves the use of another power supply with a transformer and a rectifier bridge for more power.

The current is collected and the pulse is created using a capacitor.

The bridge of the first transformer is closed by a thyristor, which acts as a cathode.

It will remain open until the capacitor is completely discharged. “Impulse” is the beginning and end of the welding machine.

To create a more powerful device, the circuit changes slightly: it is necessary to add a semiconductor thyristor and a time relay.

Homemade welding machine

The circuit is the basis for creating a welding machine, and its “heart” can be considered a transformer, which will create the necessary voltage.

It’s worth noting right away that this element must be powerful with a minimum value of 700-800 watts.

You can make a homemade welding machine using an inverter, but this requires certain knowledge and skills. Using a transformer rather than an inverter is an easier way to create a homemade machine.

IMPORTANT TO KNOW: Inverter-type semi-automatic welding machine

The transformer can be taken from the microwave. Moreover, an old device is suitable for this, or a microwave oven can be purchased specially second-hand.

The scheme of further actions is as follows:

  1. You need to carefully remove the transformer from the microwave, removing all fasteners and disassembling the base;
  2. The secondary winding from the microwave transformer must be knocked down. You can use any available tool: hammer, chisel, pliers, drill, etc. By the way, a drill should always be at hand when using spot welding. The secondary winding differs from the primary winding by a thicker wire. You also need to act carefully here so as not to damage the wire used for the primary winding;
  3. It is necessary to make two or three turns of a new secondary winding. To obtain a current of 1000A, it is advisable to take a wire whose thickness will be at least 1 cm. Physically, it will not be possible to make more than three turns, so if necessary, add another transformer from the microwave, as mentioned above;
  4. The next step is to check the winding for short circuits. A voltmeter is used for this. If none are found, then work can continue;
  5. Next, the transformer from the microwave is checked with an ammeter. If the current exceeds 2000A, then it is necessary to reduce it in order to avoid future voltage drops.

Copper wire works well for electrodes. The thickness of the wire is selected so that the diameter of the wire does not exceed its diameter.

You can use two soldering irons, or rather their tips, which can be installed as electrodes.

Current losses can be reduced by shortening the length of the wire coming from the electrode.

The wire is connected to the electrode using a copper tip; a hole can be made by drilling, using a drill bit of 8.

If you solder the tip to the wire, you can avoid oxidation, which is inevitable when you turn it on for the first time.

Next, to ensure the safe operation of a homemade welding machine, it is necessary to make a housing. The best material for this is wood.

When creating levers, the following point must be taken into account: it is necessary to create free movement of the upper lever horizontally and vertically; this can be done using special openings in the body.

If desired, you can make the lower arm in the same way.

It is necessary to provide space for the on/off switch on the back cover of the device. After installing the toggle switch, the power cable is inserted.

To eliminate the possibility of the cable falling out, it must be made thicker and thicker.

The microwave transformer is attached to the base using self-tapping screws. A terminal is put on the mount and grounding is done. All connections must be carefully insulated.

To keep the upper arm raised, you can use a regular rubber band placed on two self-tapping screws.

Watch a video about do-it-yourself spot welding in our article.


We make a spot welding machine with our own hands: their types and main elements - SibNovStroy

Welding processes play an important role in technology. One of the methods is spot welding - creating a permanent connection of parts at one or more points.

What affects weld strength

The strength of the weld depends on the size and structure of the area, which in turn is influenced by the following factors:

  • contact area;
  • electrode sizes;
  • pressing force of parts;
  • dimensions of electrode contact surfaces;
  • magnitude and time of passage of welding current;
  • condition of surfaces.

Resistance spot welding has a wide range of applications. This method connects parts from a thickness of 0.02 microns in instrument making to 20 mm sheets in metal structures. It is characterized by a welding current of hundreds of amperes, as well as low resistance of electrodes and contact surfaces.


Do-it-yourself spot welding provides the following advantages:

  • high seam strength;
  • cost-effectiveness of the method;
  • possibility of work automation.

Features of the spot welding process

The process is used for industrial purposes and in the home. The following materials are welded:

  • sheet metal;
  • products made of steel and non-ferrous alloys;
  • sectional and bent profiles.

In everyday life, spot welding is simply necessary for repairing various tools, kitchen equipment, and household utensils. The process consists of accurately aligning parts in a given position. They are installed between the electrodes and pressed against each other.

In this case, the connection point is heated by electric current to plastic deformation, as a result of which the parts are welded. The main thing for the welder is their precise fixation, creating a certain pressing force, current and process time.

The thermal impulse should be enough for the metals in the contact zone to melt and a common liquid core to form.

Spot welding machines

More and more industrial products are being manufactured using the simplest and cheapest method. This also applies to repairs. A spot welder is an extremely necessary tool for workshops. Many craftsmen purchase it because they are used to working on their own.

When choosing a device, you need to correctly determine its purpose. In many cases, you can get by with a homemade simple device when spot welding is required. The price of branded equipment ranges from 5 to 200 thousand rubles. The more features a model has, the more expensive it is.

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The devices differ in installation methods. In production conditions, stationary devices are used. Suspended models are used for production lines. They are often used in car repair shops. The most convenient for a home craftsman is a portable device.

Spot welding is powered by single-phase or three-phase alternating current. It is advisable to use inverter and capacitor devices that do not create a significant load on the electrical network.

Spotters have become popular spot welding devices. They have no ticks. One terminal of the current source is connected to the body of the part, and the other to the element being attached.

When it is necessary to fix a dent on a car, a nut or bolt is welded to this place using a special gun using a pressing method.

The defect is then corrected by pulling, after which the element is heated again and removed.

The wires from the source are made as short as possible, and the connection point is as close as possible to the editing area.

New functions are constantly being added to the devices. With their help, you can now not only weld, but also create local heating, as well as apply patches. Multifunctionality makes them heavier, more powerful and more expensive.

Pros and cons of different models of spot welding machines

The simplest spot welding, done with your own hands, is only possible with manual control, which allows you to adjust the welding current each time and very roughly control the duration of the work.

The automatic control system makes it possible for non-specialists to perform high-quality welding. Due to this, labor costs are reduced and scrap output is reduced.

The quality of the connection depends on the amount of compression of the parts. The simplest is the manual drive, most often used for household work. This significantly reduces the cost of the device.

The mechanical drive is one of the most popular and is used in many welding devices.

Pneumatics and hydraulics create significant contact pressure that can be adjusted. Such devices are usually contained in a stationary spot welding machine used in industry.

Portable devices are widely used and are sometimes not inferior to stationary powerful devices. The spot welding machine is made in the form of hand-held pliers and can join sheets of about 5 mm thickness.

Manual pressing drive using a lever makes it possible to create forces of up to 150 kg. Thanks to the versatility of the device and the simplicity of the operation, high-quality spot welding is achieved. The price of such devices is quite reasonable, which gives them certain advantages over their expensive counterparts.

Inverter devices have gained popularity in spot welding. Despite their high cost, they are well received due to their lightness, versatility, small size and ability to connect to a household network.

Do-it-yourself spot welding machine?

The simplest device for spot welding is made by hand without adjusting the current. The welder remains able to control the process only by changing its duration.

Basic elements of a homemade device

  1. Power transformer.
  2. Electrodes made of copper or graphite.
  3. Switch.
  4. Lever arm.

Device characteristics

No matter how complex a spot welding machine is, the transformer is always its main part. It must have a power of at least 1 kW. The higher it is, the better. The output voltage is about 2 V. The current reaches 800 A, and it can weld sheets up to 1.5 mm thick.

The body of the homemade apparatus is made of plywood, and the moving parts (levers) are made of wooden blocks. After assembly, the transformer is attached to the base with self-tapping screws and connected to grounding. Contact electrodes are installed at the ends of the levers, and the secondary winding wires are connected to them. The upper lever is spring-loaded so that it is raised in its initial state.

The parts are placed between the electrodes. When acting on the upper lever, the electrodes converge and press the sheets against each other. When you press the switch for 3-4 seconds, welding current passes through the sheets. After turning it off, you need to wait for the seam to cool down.

If more powerful spot welding is required, 2 similar transformers with connected windings are used.

To increase the output voltage, a thick wire is connected in series through secondary windings with the same number of turns.

To avoid making a mistake and not turning them on out of phase, you can experimentally pass a thin wire through the transformers and then measure the voltage at the output.

When a powerful spot welding machine is required, you can make it yourself from a conventional welding transformer, adding another winding with the required number of turns. It is important that it matches the power of the electrical network. The length of the wire and the number of connections should be kept to a minimum, since they lose power and generate heat.

Copper rods are used as electrodes. To do this, you can use a soldering iron tip. The advantage of copper is that it does not weld to steel parts and heats up less.

It is also necessary to take into account that through the electrodes compression of the parts being welded is created among themselves. Over time they lose shape and wear out and need to be replaced.

The tips and wire must be soldered, since the contact point oxidizes over time.

The controls in the device are a lever and a primary circuit switch. The pressing power increases with increasing sheet thickness. Therefore, the lever must meet the requirements of the welding technology. The switch is installed in the primary circuit.

If it has high power, you can use magnetic starters. Then a switch can be installed on the lever so that with one hand you can create a pressing force and turn on the welding current. The other hand remains free to work with parts.

If the primary winding of the device is connected through a laboratory autotransformer (LATR) with a power of 2-3 kW, the welding voltage can be adjusted. You can make a secondary winding directly on it.

The result is a welding machine with current control. The weak point of the LATR is the motor with the wheel, which, as it wears out, begins to short-circuit several turns, and the winding begins to burn.

An autotransformer with stepwise switching of windings is more reliable.


Despite the large selection of devices, their cost is still high, and it is also difficult to select the necessary parameters. It is easy to find everything you need to assemble the device. It is important to understand how spot welding works and what its purpose is.


Do-it-yourself spot welding: how to do it?

Do-it-yourself spot welding will be of interest to those who need a welding machine, but who do not want to spend a lot of money on it.

In this case, resistance spot welding is the best option, because You can assemble such a device literally from available materials.

In the article you will learn about how to assemble the device at home, what tools and equipment will be required for this, as well as the pros and cons of this type of welding.

The diagram and video will help you complete the entire process yourself and get a high-quality product that will last for many years.

How does this type of welding work?

Spot welding is not at all an amateurish type of work, which is used only for home use - it is widespread both on an industrial scale and in private production.

Spot welding is contact work to connect two elements in the desired position. This type of welding is similar to seam and analogue, but still has its differences and nuances.

The most significant advantage of spot welding is that any person more or less familiar with electrical engineering can make a machine for it (including from old microwave parts).

In addition, such a device will be in no way inferior to machines produced at a factory - the difference is that a home device can only be used on a local scale, but for personal needs you don’t need more.

If resistance welding is a new process for you, then it is better to first delve a little into this process and understand how the machine works. In this case, it will be much easier to assemble it.

Welding of elements occurs as follows: first you need to fix the metal parts in the position you need and place them between the electrodes of the device.

The parts are then heated until they become pliable and are then joined together.

The parts are heated by a pulse of electricity, the duration of which is no more than 1 second.

Its task is to melt parts of the parts and make, at the place where it is directed, something like a liquid bath, the diameter of which is 12 mm.

After the pulse has completed, the parts should remain fixed in the desired position for some time in order to have time to cool down and better connect with each other.

The advantages of spot welding are obvious: the low cost of producing the device itself (it is assembled practically from improvised means and with your own hands), significant energy savings, high strength of seams and process automation (in production, machines are used that can produce up to 600 points/min).

This type of welding has only one drawback - you will not be able to make a sealed seam, although the resulting options will be quite strong and durable.

The welding diagram will help you better understand how it works.

As can be seen from the operating process, the main task of the device is to heat the parts to the melting point.

The heating power of different devices differs and you need to know what power and duration you need.

For example, for stainless steel it is better to use short heating, and for carbon steel - vice versa.

In addition, the welding machine must provide significant pressure on the parts being joined, the peak of which is reached at the end of heating. Without this, a high-quality connection of parts will not work.

Good spot welding electrodes imply high thermal and electrical conductivity and do not have problems with mechanical processing, so not every material is suitable for manufacturing.

You can use: bronze with an admixture of cobalt or cadmium, electrolytic copper and alloys based on it with tungsten and chromium.

To assemble the device with your own hands, it is best to use EV grade copper alloys.

During manufacturing, it is important to remember that the diameter of the thinnest element of the apparatus should not exceed the size of the melting point (its diameter should be 2-3 times smaller).

Watch a video on how to use spot welding for home use.

Stages of creation

As already mentioned, do-it-yourself spot welding can be assembled literally from available materials.

You need to start work by assembling the inverter. The use of an inverter will make the operation of the entire device possible.

To assemble it, use parts made in the USSR:

  • diodes;
  • capacitors;
  • chokes;
  • transformers.

If these parts are used, complex additional configuration will not be required.

Most often, the device is made from parts of an old microwave, which you may have in your home or at someone you know. This spot welding of old microwave parts has a power of about 800 Amps.

It is enough to weld fairly thin sheets of metal. As a rule, for home use more power is not needed.

Try to choose large rather than small microwaves, because... larger models have a more powerful transformer, which will be the basis of your welding machine.

The transformer looks like this: it is a core with two windings, the first of which is made of thick wire with fewer turns.

The transformer is held together by welds, so to get to its windings, you need to remove them (this can be done with a hacksaw or grinder).

The removed transformer must contain an intact winding and a core divided into 2 parts, cleaned of paper and glue that fixed the windings.

Next you need to wind the second winding of the transformer. You will need a cable that fits the slot in the transformer (approximately 7 mm), which must be wound in two turns.

The transformer needs to be attached to the base, this can be done with epoxy resin - to do this, squeeze the mechanism with a vice and leave for a while so that the material can stick together.

The video below shows welding on a microwave transformer.

Thanks to the secondary winding, the power of the transformer will be approximately 2 W.

If you want the power of the device to be higher, then you will need another transformer from the microwave, which will need to be connected to the first one.

This is what the transformer circuit looks like

When both windings of the device are connected, you need to check the current strength.

It should not be higher than 2000 Amperes, otherwise significant power surges are possible not only in your apartment, but also in all neighbors.

You can connect the transformer using the secondary winding.

In this case, the amount of welding current will double - if it was 220, it will become about 500.

For connection, use wires with a diameter of 10 mm. The connection diagram will help you do everything correctly, but if the technology is broken, then there is a high probability of a short circuit.

The voltage will go out to the first winding, and at the output you need to turn on a voltmeter that can work with alternating voltage.

You need to choose the direction of operation of the windings based on the following options: there is voltage in the device or there is no voltage.

In the primary circuit one can observe the presence of windings with opposite terminals.

The voltage of these windings is usually equal to ½ of the input voltage, its increase and transformation will occur in the windings following this one, but the coefficients will be the same.

Below is a diagram of how to make a spot welding gun.

After turning on the secondary windings, you need to add up the difference in the resulting potentials - then the voltmeter will show twice the difference for each of the windings.

If the device shows “0”, then the resulting values ​​will be equal, but with opposite signs.

Therefore, each connected pair of windings will have similar terminals.

Watch the video on how to properly remove and reassemble a spot welding transformer.

Transformer pliers

For the device to work, you need not only a transformer, but also pliers. The pliers are a mechanical part of the machine.

Therefore, spot welding necessarily requires the making of pliers and electrodes, without which the operation of the device is impossible.

To make pliers, you need to sharpen the rods of the electrodes that you will use, because... otherwise they will become deformed. Electrodes cannot work forever and lose their properties over time.

The wire that connects the electrodes and the current transducer does not need to be long, otherwise it will be inconvenient to work. Also there should not be many connections, because... each of them will take power.

It is best to make copper lugs at the ends of the wire, which can connect the electrodes to the wire.

The tips are soldered so that the fit is as tight as possible, because a poorly soldered connection will cause a significant loss of power of the device and even its breakdown.

Soldering the tip and wire with your own hands will not be so easy due to the significant diameter, so when working, use solder tips, they will make the work easier.

This will also help when it comes time to replace the electrodes, because... Replacing old rods with new ones is not very convenient.

A connection made using a solder tip is easier to remove oxidized areas from.

Electrodes can be purchased at any market with electrical appliances. They look like small rods (diameter slightly more than 1 cm). The electrode diagram is below in the photo.

If the microwave transformer has poor welding, you can use electrodes from soldering irons - to do this, you need to remove the tips from them.

Connect the electrodes with a short cord without unnecessary connections.

To make the connection between the electrode and the transformer, make a hole with a drill or drill, but you can also use a copper tip.

To secure it tightly, tighten the bolt as much as possible, and to avoid the oxidation process, solder the wire to the tip.

But if you plan to use the welding machine frequently, then it is better to attach the electrodes with a bolt, because... in this case it will be easier to replace them.

It is best if the connecting material is made of copper.

Welding machine switch

To make the welding process possible, you will need a switch lever. In order for the parts to be connected, an appropriate compressive force must be provided between the electrodes.

To enhance the compression of parts, the body of the welding machine must be equipped with lever clamps.

For home work, a device with a lever that can withstand 30 kg is suitable (for comparison, for industrial welding this is at least 50 kg).

The welding machine switch is mounted in the primary processing circuit, however, if you have equipped it with a lever, then it is best to attach the switch to it.

Then the machine will be turned on by pressing on the lever - this will turn on the current, and with the other hand you will need to fix the parts to be welded.

Assembling spot welding is not too complicated, but quite a responsible process - you need to be careful about the correct connection of parts to avoid short circuits and failure of the device.


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