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

Often there are situations in which it is necessary to connect metal products or repair various structures. To deal with this, you need to know how to do your own spot welding. The device for its implementation can be assembled independently at home. This will greatly simplify the entire process and save you from large financial costs.

General information

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

Main advantages

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

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

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

Brief technology

Welding of any product follows the same principle. At the same time, it is important to carefully carry out all operations and not to miss even the smallest nuance. Only in this case can a perfect seam and its strength be achieved.

The entire technology consists of several stages:

1. The parts to be joined are aligned in the desired position and securely fixed.
2. They are then placed between the electrodes of the welding machine and squeezed tightly.
3. After that, 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 action of the current stops, the molten material solidifies and reliably holds the parts together.

Preparatory activities

Proper preparation is considered the basis for the successful implementation of any type of work. It allows you to take everything you need to carry out a smooth process. For the success of resistance welding from a welding machine with your own hands, you need to choose the right electrodes and all the necessary tools.

Choice of electrodes

The main attribute of resistance welding is the electrode. With its help, the whole process is carried out, therefore it is very important to buy the best option for carrying out a certain work.

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

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

1. For welding 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 mechanical damage.

Experts do not recommend filing them, as this can lead to cracks and irregularities. Due to such defects, the welding process will be 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 an appropriate unit. It is done using a certain set of tools and the minimum amount of materials available to everyone. In the process of working on the device you will need:

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

Equipment manufacturing

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

Power supply

The spot welder is made on the basis of a pulse source using the principle of capacitor discharge. Thanks to it, you can connect parts up to 0.5 millimeters thick.

Features of the operation of such a power source:

1. The required current is generated at the output of the secondary winding of the transformer.
2. The discharge is controlled by thyristors.
3. The required charge is accumulated on the capacitor plates. In this case, the auxiliary circuit of the transformer must be disconnected.
4. Diodes are used as signal rectifiers.

If necessary, you can use the diagram of the device used. With its help, it will be easier for beginners to achieve the desired result.

The discharge of capacitors is carried out as follows:

1. During the opening of the main circuit, the installed capacitors are charged.
2. After turning on the welding machine, they are discharged to the winding. The strength of the discharge is changed using thyristors.
3. The whole cycle is repeated when the device is turned off.

When welding larger workpieces (up to 4 millimeters thick), it is necessary to increase the discharge power several times.

Transformer winding

One of the main components of a spot welder is the output transformer. With its help, the required current is supplied to the electrode. Such a device can be made by hand and used in a general design. To do this, you need to follow a few simple steps:

1. The core is removed from the broken transformer. It is necessary to choose one that will consist of steel plates with a cross section of at least 60 square centimeters.
2. The primary winding is wound on one of its racks. For these purposes, it is best to use copper wires with a diameter of no more than 3 mm.
3. A special transformer paper is placed on top of the winding. It performs the function of electrical isolation and helps to protect the device from premature failure.
4. The ends of the wire are fixed on the terminal block, which is located at the top of the core.
5. The secondary winding is wound on the other rack. It is made in the form of two turns of the bus, which is assembled from copper wires.
6. For added safety, it is wrapped with any kind of insulation.
7. Transformer paper is also placed on top, and the ends of the wire are brought out to the block.

If everything is done correctly, you will get a transformer with a capacity of 3 thousand watts.

Assembling contact blocks

For the manufacture of a spot welder, a pistol-shaped contact block is most often used. The assembly process is quite time consuming and can take a lot of time.

Step-by-step instruction:

1. First of all, 2 plates of textolite or getinax are taken. Their thickness should vary between 8-10 millimeters.
2. Two blanks are cut out of them, which resemble a pistol in shape. Their length should not exceed 25 centimeters.
3. In the front part of the parts, semicircular grooves are made for installing the electrodes. Their radius should be approximately 6 mm and their length should be 6 cm.
4. Having stepped back from the extreme cut a third of a meter, they grind a rectangular groove to install a nut that will secure the electrode.
5. In the place where the original workpiece is bent, the necessary holes are drilled for attaching the start switch.
6. Holes are made across the entire surface of the two parts of the gun to connect them to each other.
7. Then grooves are made, which will ensure an unobstructed cable entry.
8. An electrode with a length of at least 60 mm is made from a copper rod with a diameter of 8 millimeters.
9. At one of the edges, a thread is cut for the nut used in the device.
10. The tip of the electrode is sharpened as a cone with a rounded end.
11. At the next stage of work, all parts are assembled. For this, a nut is screwed onto the electrode.
12. Then a wire is soldered to the end, which is connected to the trigger.
13. Then the switch is inserted and connected.
14. Both halves of the pistol are firmly fastened together.

Safety engineering

Any welding process, even in the case of do-it-yourself microwelding, must be carried out in compliance with safety measures. This will not only preserve health, but also prevent many negative consequences. In addition, the welder must use special protective equipment that will protect him from the effects of hot metal and electric current.

Among the main safety requirements, the following are worth highlighting:

1. Grounding of all potentially hazardous parts of the equipment. Such a measure will help to avoid electric shock.
2. Before starting work, it is necessary to check the operability of the device.
3. Wear protective equipment to avoid electric shock.
4. All controls must be free of high voltage.
5. The device must use wires with a large cross-section.
6. Use gloves that will protect your hands from accidentally flying away metal splashes, as well as a special head shield. The latter will protect the welder's eyes from the negative effects of a bright flash.
7. Wear respiratory protection or work in a well ventilated area. This is necessary so that harmful vapors released during work do not enter the lungs.
8. All emergency stop buttons must be in working order. At the same time, access to them must not be blocked by any objects.
9. It is advisable to fence off the place of work with shields in order to avoid various negative consequences that arise in the event of an unforeseen situation.
10. The likelihood of injury from moving parts of the machine should be minimized as much as possible.

Spot welding is a rather time-consuming activity that requires not only special devices, but also certain skills in the work. Moreover, the entire process can be done at home and get the desired result with minimal cost. With the right approach to business and adherence to safety procedures, you can increase the likelihood of a positive outcome of the case and reduce the risk of any injury.