With this controller, you can control the power of a spot welder. This is done by setting three timings: the pre-weld pulse, the weld pause and the welding time. You can use it for a DIY spot welder made of a microwave oven transformer (MOT), for the Kende DN-100E welder and for the repairing of the Sunkko 788 welder. I have developed the D.I.Y spot welder because I needed a special spot welder for the building of my Maxun One solar bike. It turned out that the spot welder is being built by many people worldwide. 

See the article HERE.

Note: for the repair of the Sunkko 788, order the switch-not-soldered version, because the switches have another position.