Repair Home Items With This Spot Welding Machine

Welcome to ERL Engineering! In this video, we'll guide you through the process of creating a powerful spot welding machine using a repurposed microwave oven transformer. Learn how to modify the transformer for optimal spot welding performance and witness its incredible power in action.

1. Old Microwave Transformer
2. Thick wire (9 SWG or lower & atleast 3 feets in length)
3. Power cord for connection between AC line and transformer input

First, we disassembled an old microwave oven transformer, removing its secondary winding that provided a whopping 2000 volts. To make it suitable for spot welding, we carefully rewound the secondary side using 35 square millimeter wire, creating a two-turn configuration. The addition of ring thimble connectors ensures easy and secure connections.

Watch as we demonstrate the transformer's power by short-circuiting the output with a thick copper wire, showcasing its ability to melt the wire within seconds. We then put our DIY spot welder to practical use, repairing everyday items like a broken tea strainer and a metallic mesh bucket.

However, we want to emphasize that this spot welding machine isn't recommended for lithium-ion cell or battery welding. We haven't incorporated a dedicated circuit for pulsed current output, a crucial element for safe and effective spot welding of lithium-ion cells. The ideal output for such applications is between 4 to 12 volts, with a current exceeding 100 amperes and a pulse duration ranging from 10 to 100 milliseconds.

Stay tuned for more exciting engineering projects on ERL Engineering, and don't forget to subscribe for future DIY creations and innovative solutions!