Those copper blocks about halfway down look a whole lot like sinker EDM[1] electrodes, which makes me question the accompanying quote: "instead you have to use magic electrolysis (like they taught you at school)". Spark erosion isn't really electrolysis in any way I can think of, and is sufficiently awesome of its own right that it deserves more attention :)

[1] https://en.wikipedia.org/wiki/Electrical_discharge_machining...