My high school chemistry teacher made sure we'd never forget which
electrode is which (not that it will be of much help to you).
Reduction occurs at the Cathode (reduction being the opposite of
oxidation, you put the work on the cathode(-)).

I should add that my teacher's name is Ron Crampton. Maybe you could
think put Rust at the Cathode?

Steve

Grant Erwin wrote:

What do you figure the reaction is that's taking place at the carbon
electrode? I guess I sort of thought it had to be a steel electrode.
Else why not just use copper? At any rate, this is my first time EDRing
and I'm doing a small piece - a steel 2" caster - and I'm just using a
piece of 3" steel square tube as the anode (cathode? boy I could never
get those straight). It's bubbling away nicely. I figure I'll toss the
solution after I'm done. The cost of a tablespoon or two of washing soda
isn't worth it.

Grant

Orrin Iseminger wrote:

On Tue, 05 Apr 2005 11:31:03 -0700, Grant Erwin
wrote:


I figure cans (e.g. soup cans) are steel plated with something. What I
really want to know is if they make acceptable electrodes for
electrolytic
derusting.

GWE



Grant, I tried coffee cans and they only lasted about a day. They'll
fall apart and a lot of unused steel winds up in the bottom of the
vat.
It was a messy situation.
Do you have any arc-furnace foundries in your area? Do you know
anyone who works on an aluminum "pot line?" Both use carbon
electrodes and carbon makes a very good material for electrolytic
de-rusting.
That said, the binding agent in some carbons will dissolve rapidly in
the electrolysis vat. I've had carbon electrodes disappear overnight.

On the other hand, I've had some 1/2" thick graphite electrodes that
lasted about a year.
Another place to get carbon (graphite) is on eBay. You cannot simply
do a search for graphite, however, or else you'll get ten million hits
on everything from golf clubs to fly rods. You'll need to search for
graphite stock, graphite plates, graphite blocks, etc.
The nice thing about using graphite electrodes for electrolysis is
that the solution stays clear and clean. If you use steel it turns
rusty red and gets worse every day. Finally, the rust particles start
settling out on the part you are drying to de-rust. It's a no-win
situation.
Don't try stainless, either. That's another story. Suffice it to
say, don't believe anyone who tries to tells you stainless won't be
affected. It will. And, it'll create a hazardous waste product that
can be difficult to dispose of. Stainless chromium chromates
poison.
Regards,

Orrin