Build an Electrolysis Tank and save your old cast iron! One of the questions I get asked most often is how to build an electrolysis tank. When a friend decided to make one for himself, we filmed the process, and here’s a quick video showing how it works. There are lots of ways to restore cast iron, but this has always been my preferred method. Why? Because it’s a fascinating process and, more importantly, it won’t harm fragile vintage pieces. P.S. Four pans were “saved” in the making of this vid