Want to metal etch, but all modern Battery jump starters won't work. What to use? in Tools and Tool Making Posted September 7, 2019 I made mine from parts I got off of Amazon. Switchable between AC and DC using a tapped transformer for either 6v or 12v output. If you are comfortable with electrical work I can post the scematic and parts list. Just keep in mind when you use a transformer to lower the voltage the amperage goes up, and when it comes to electricity it's the amperage that will do you in.