Quite often during various repairs it happens that it becomes necessary to apply spot welding technology. Today there are many units that can be used for this purpose. However, you can assemble a spot welding machine with your own hands. But for this you need to understand this issue.
What is do-it-yourself spot welding?
This is a type of contact soldering, in which a current (electric) passes through a metal, which is heated at the contact point of both parts. At this point, the material melts, and most importantly - at this moment a welding core is created, the diameter of which can be in the range between four and twelve millimeters. Moreover, it has the shape of lentils.
Spot welding proceeds in several stages:
1. On the first of them, parts that are fused are compared with each other in the required position. Then they are located between the electrodes, after which they are strongly pressed against each other.
2. The parts are heated, which makes them sufficiently plastic, and they are deformed.
In order to be able to spot welding with your own hands at home, you must observe some conditions:
1. Maintain a constant speed of movement of the two electrodes.
2. Keep the required pressure value, as well as the full contact of the parts to be welded.
The advantage of this method is that it is environmentally friendly. And the seams obtained as a result of spot welding are characterized by high mechanical strength. However, there is a drawback to this method - the seams do not have tightness.
Application area
DIY spot welding is most often used during the repair of household appliances. Although the scope of this method is great - various work with aluminum, cable or repairing small kitchen utensils. Homemade welding can also have the most diverse configuration.
They can be small portable, and can be represented by devices of quite impressive sizes, which are used to perform voluminous work. At home, spot welding with your own hands is most often performed on tabletop units that can be used for non-ferrous and ferrous metals.
How to make a welding machine yourself?
Before you start creating it, you need to understand that the machine should turn out to be quite powerful and easy to operate. A powerful machine is able to combine high quality sheet steel with a thickness of 3 mm.
The main structural part of the welding machine is a basic transformer. It is best to use a mass production device for this. For example, OSM-1. In this case, the primary winding of the transformer must remain unchanged, it must contain at least 200 turns. But the secondary should be replaced by a more powerful one. In the first case, it is better to use a wire PEV 2-1.9, and in the second - PVZ-50.
It is not necessary to adjust the amount of current in the apparatus. During welding, it is worthwhile to focus on the duration of heating, as well as visually control the color. Holders for electrodes can be made of duralumin rod. Its diameter should be 30 mm.
The lower electrode must be made stationary. Then isolate it from the mounting bolts and cheeks with washers or duct tape. It is desirable to choose electrodes copper, diameter - equal to 12 mm. Secure them in the holders with two bolts or a brass washer.
Next, you need to take any springs. For example, you can use these from the clamshell. The holders together with the electrodes must be parted with a spring in its original position. The welding spot machine should be connected to the network using a circuit breaker, which should be designed for 20 A, at least.
The unit itself can control the magnetic starter, which must be switched on by pressing the pedal. The secondary winding and transformer housing must be earthed. Parts to be welded must be clamped between the electrodes. The current flowing between them will warm the metal. After that, the electricity is turned off. And the compression force of the electrodes increases. The result is a welded joint.