Power Spot Welding Machine / Build Your Own Efficient Welder

 

Power Spot Welding Machine / Build Your Own Efficient Welder

You can make a homemade welding machine using two microwave oven transformers but with the necessary caution to prevent high voltage and current. Here is how to do it:

Materials Needed:

·            1. Microwave Oven Transformers x 2: Main power source

·         2. 12V Relay Above 40A: Controls power switching

·         3. Push Button: To activate the welding circuit

·         4. Copper Welding Pen  x 2:  To deliver the welding current

·         5. 10mm Copper Wire 5 Meter : For secondary windings

·         6. High Amperage Cables:  For connections

·         7. Insulation Tape & Heat Shrink Tubing: For safety

·         8. Cooling Fan (Optional): To prevent overheating

Step-by-Step Instructions Spot Welding Machine:

1. Modify the Transformers:

• Unwind the secondary winding (high-voltage coil) from both the Transformers carefully using a hacksaw or a chisel.

• Substitute it with thick copper wire (16-30 turns) to provide a low voltage, high current output (approximately 10-14V  but + 100A of current).

• Wind the secondary winding in the same direction for both transformers so that the current remains in phase.

***Video Screenshot***

2. Connect the Transformers for Spot Wleding:

Join the primary windings of the Microwave Transformers in parallel (same AC 220V input voltage) to ensure equal current distribution.

Interconnect the fresh wound secondary windings in parallel or series based on the required voltage and current balance.

3. Wiring the Relay and Push Button:

• Apply a 12V DC supply to switch on the 40A relay.
• Use the push button to connect the relay coil circuit as a trigger switch.
• The relay must switch the main side of the Transformers to energize the welding power in a safe manner.

4. Attach the Welding Pens:

Use heavy welding cables to connect secondary winding outputs to the welding.

Provide adequate insulation and tight connections to prevent short circuits.

***Diagram***

5. Safety & Testing:

• Wear protective gear, welding helmet, and safety equipment.

• Test with a small piece of metal to check arc formation.

• Add a cooling fan to prevent transformer overheating.

• When overheating occurs, wind the secondary with additional turns to cut current down.

This setup can be used as a basic spot welder for any nickel sheet of metal. Do not attempt this if you have no prior experience with high-current circuits since it is dangerous.