170 Amp MOT Stick Welder

[scorch]

Home made Microwave Oven Transformer (MOT) stick welder. I based my design on the welder by Daniel B. Hartman (Dan's Workshop). This welder is made from four transformers from old microwave ovens. The transformer secondary coils were rewound, to achieve welding voltage, with 6 AWG solid copper wire. I included two fans from one of the microwaves for cooling. The power adjustable so it can be used with various sized of welding rod. The SCR module used to adjust the power is mounded to a homemade heat sink made from two old aluminum frying pans.

Input: 240V, ~25 Amp
Open circuit voltage: 47 Volts
Welding current: 170 Amps
Rewound transformer secondary coils with 6 AWG stranded copper wire.
Variable power provided via SCR module

Welder installed on the shelf of a cart that I use for welding.


Welder removed from the cart with the top cover removed.


The SCR for the power control mounted to a homemade heat sink made from two aluminum frying pans.