Tungsten electrodes are made from several alloy varieties and can be identified by the color of the band of paint on the tip. While most electrodes work with most metals you’d be welding in an automotive application, some electrodes will not work with all metals. To keep it simple, Miller’s Josh Sprinkle recommends buying 2 percent lanthanated (royal blue) or 2 percent ceriated (gray) tungsten. They are sold in different diameters, too, and you choose them based on how many amps are needed to weld through the thickness of the material you’re working on. Use 1⁄16 for welding thinner materials using 100 amps or less, 3⁄16 for 100–150 amps, 3⁄8 for amperages greater than 150. Generally, a 3⁄16 tungsten will work for most materials you’ll encounter when working on cars.