I've been doing EDR (electrolytic derusting) for a few weeks now. Today I went to the legendary Midway Swap Meet for the last time, as this place which has been open since the demise of the once-ubiquitous drive-in theaters, is closing for good, to be replaced by a (shudder) Lowe's. There were lots of people at the swap meet and I found a nice DC ammeter for a real nice price. I got home and headed down to the bucket where I'm EDR'ing my way through six old Ridgid pipe threading dies. I wired in the ammeter and discovered I wasn't running nearly enough current, only about 0.7 amps. I remembered the conventional wisdom which was to move the electrodes closer to the workpiece until the amperage was about right. I tried that. You know, it just didn't work for me. I didn't find much variation at all in actual amperage as I varied the electrode distance. Then I tried adding more washing soda. As I'd sort of expected, the current went right up. At a tad over 2 amps it's sizzling right nice now.
So my question is, to the person or persons who wrote that if the amperage is too low, vary the distance, are you *sure* this worked for you? I am a total believer in experimental science, and the only procedure that is believable is one that's reproducible.
Grant