One of the most critical parts of spot welding batteries is timing. While [Robert Dunn] admits that a 555 timer or even just a manual switch and relay could have done the job, he opted for an Arduino Uno with a
(There could be chemical reasons for the choice too, for welders at least. Magnesium silicate is used in some high-temperature pottery glazes, and it's also used as a weldingflux, for gas welding at least.) The ability to precisely draw talcum powder onto a surface could be mechanically ...