electrolytic derusting?

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.
Reply to
Grant Erwin
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Crank up the voltage. If your power supply isn't adjustable or can't handle the current, then upgrade the power supply.
Generally you should be pumping enough current thru the water to make it warm and even hot, which generally means 10 amps or more. Once you get that much power going in you'll probably find that distance to the electrode doesn't matter very much.
Reply to
Greg Menke
Hi Grant,
I can't offer you any help whatsoever. I was hoping you can direct me to a source of information on how the process of EDR works and how to set up my own system.
Reply to
Increasing the washing soda is what worked for me, until I got about 7 amps.
Reply to
Athough I do more electrolytic "rusting" than "derusting," the same rules apply.
You can increase the current (and speed of rusting/derusting) several different ways: 1. Increase the voltage 2. Decrease the distance between the anode(s) and cathode(s) 3. Improve the quality of the electrolyte
Now that you have a meter for measuring, try it yourself. Set up your system with pure, clean water. Turn it on. Note the current. Now dump in your washing soda (I use baking soda). You'll be shocked by what you see.
You can do similar experiments by varying the distance between the electrodes. Just be careful not to get them too close unless you have some kind of current limiting circuit.
Here's my setup if you need ideas:
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=-=-=-=-=-=-=-=-= Rob Skinner La Habra, California
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Reply to
Rob Skinner
You can download an eight page writeup from this site:
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Reply to
Orrin Iseminger
If the "electrolyte" is not strong enough, varying distance won't do much. If too strong, likewize. With the right mixture you would be able to see the current change with distance.
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