For the occasional use of spot welding, it is impractical to buy an expensive machine. The way out of the situation would be to make contact welding from the microwave with your own hands. More precisely, you need not the microwave oven itself, but a high-voltage transformer located in it.
Content
- Spot welding: advantages and disadvantages
- Removing and reworking the transformer
- Electrodes for apparatus
- Welder assembly
Spot welding: advantages and disadvantages
Any welding method has its positive aspects, contact ones are:
-
Minimum energy consumption. - High strength of the resulting compound.
- The ability to weld sheet metal and other thin parts.
- Possibility of welding low-melting metal.
The disadvantages include the leakage of the weld, and the welded points are voltage generators.
When making a welding machine from a microwave with your own hands, you will need:
- Microwave transformer. For a powerful apparatus, you need to get two transformers.
- Thick copper solid wire.
- Levers to be used as hold-downs.
- Reliable bed on which the device will be located.
- Copper electrodes can be used for welding.
Removing and reworking the transformer
The main part of homemade microwave spot welding is the transformer. It is removed from the working microwave. The higher its power, the better the equipment will be. When disassembling the microwave be careful: Large capacitors can store life-threatening voltages. To avoid electric shock, you need to short-circuit the contacts of the capacitors (this can be done with a screwdriver).
After removing the transformer, it is required to remove the secondary winding from it. It can be sawed with a hacksaw or cut off with a chisel. And also you need to remove the shunts located on both sides of the transformer.
After removing the winding and shunts, you will have to make a new winding so that the transformer can deliver currents higher than 500A. This requires a copper wire with a diameter of 1 cm or more (you can use several wires to achieve the desired cross-section), 2-4 turns are enough to obtain the required currents. To increase the power, several transformers can be used, in which case they are connected in parallel. If several transformers are involved in a homemade device, the winding on them must be common, but it is important not to mix up the leads in order to avoid a short circuit.
If the current is too high, power surges can occur in the mains, so you should carefully use powerful welders in a city apartment in order to avoid damage to household devices.
Electrodes for apparatus
In spot welding, electrodes perform several functions: supplying current to the welding zone, removing heat, compressing the parts to be joined. The quality of the work performed will directly depend on the shape and size of the electrodes. Their shape can be either straight or curly, and the diameter must be higher than or equal to the diameter of the working wires.
The requirements for resistance welding electrodes are simple: they must withstand the operating temperature, conduct heat and electric current well, and be easy to process (sharpen).
Based on these requirements, copper alloys are ideal electrode materials.
Welder assembly
Most often, homemade devices are made stationary. The electrodes are installed in tips, which are attached to the ends of the levers, which act as clamps. The latter are easiest to make from a wooden bar. The wires from the winding must be soldered to the electrodes.
Soldering is highly desirable, because if you connect by crimping, then additional resistance will appear at the junction. The lower arm is stationary and must be secured to the base. The upper arm must be strong, as it requires a lot of compression force to weld thick parts. In addition, the lever must be spring-loaded so that the electrodes are open in their original state.
The primary winding of the transformer must be grounded. And also the body of the device is grounded if it is made of a conductive material. When assembling a microwave welder with your own hands, you need to remember that transformer voltage is 230 V, it is considered potentially life-threatening, therefore all conductive parts of the device should be covered in a housing.
Since the device gets very hot, it is highly advisable to come up with a cooling solution. For these purposes, a cooler from the computer system unit may be suitable. The power button can be positioned anywhere convenient for work. In addition, pedal power can be applied.
