However, you want the electrode at negative voltage with respect to the workpiece. I built the wand using the red wire, since I think of it as the active thing and the workpiece as ground. The circuit is completed causing electricity to flow and the electropolishing reaction to occur on the workpiece surface. To use this you soak the cloth in electrolyte and touch it to the workpiece with the power connected. I just use one layer of fiberglass, more than that it is difficult to get much current to flow. I wrap the electrode with the fiberglass tape and secure the fiberglass with electrical tape. The electrode is wrapped in fiberglass tape from the auto parts section of a hardware store. I used a high current clip in between the alligator clip and the electrode because it clips to the electrode a little bit more securely, but it's not totally necessary. The electrode is connected to a banana plug to alligator clip cable. It's important to grind off any pointy corners or sharp edges because those will cause arcing a lot sooner. Here I've made the electrode from a scrap piece of 12ga stainless steel cut into a rectangle. The cloth holds the electrolyte liquid and conducts electricity but prevents arcing. The wand is made from a metal electrode wrapped in a cloth to keep it from making direct contact with the workpiece. One end of the power supply connects directly to the workpiece (the piece you're polishing), and the other connects to a wand that you do the polishing with. Fortunately, it's not hard to do with a standard bench power supply and a little polishing wand that you can either DIY or use some fancy parts. There are some commercial tools out there for electropolishing stainless steel that look really great but are prohibitively expensive, even the cheapest costs nearly as much as the TIG welder I used to make these welds in the first place. If the surface is not properly passivated, your stainless steel might not be so stainless. This means the surface is covered in an iron-free chromium oxide layer. As a side benefit, cleaning your stainless steel using electropolishing helps it become properly passivated. For the details, you can read the electropolishing wikipedia entry. Electropolishing works by accelerating an oxidation reaction of an acidic electrolyte on a metal surface using electricity. The best way to clean stainless steel without these problems is by electropolishing. Additionally, mechanical polishing requires getting the polisher in what might now be a limited space.
If you've polished the steel to a different texture before welding, it can be difficult to get the original texture back. Mechanical polishing using a surface conditioning pad works nicely to remove the color, but has disadvantages - any mechanical polishing will change the surface texture. These look nice, but if you want your stainless steel to look like stainless again, a polishing step is required. When stainless steel is heated to welding temperatures, it turns lots of pretty colors - gold, red, purple, blue - depending on the temperatures.
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