"Grant Erwin" wrote in message
...
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.

I use a slab off an old Poco 3 EDM electrode for my wipe-type derusting.
It's lasted for about three years and I detect no sign of wear. I wrap it
with cotton batting, or, if I want to be more aggressive, one of those green
abrasive pot-scrubbing pads. They contain silicon carbide so don't use them
on anything you don't want scratched.

For use in the tank I have a sheet of steel I cut off the front and one side
of an old clothes washer, before I threw it out. I made it into a cylinder
that surrounds the inside of a 5-gal. plastic bucket. A disk sander cleaned
off one side. I left the paint on the outside.

The ends aren't fastened together; it's just a bent sheet. It's lasted for
two years and looks like it has a few more years in it.

--
Ed Huntress