Michael D. Porter wrote:
> Ken Streeter wrote:
>
>
> > I wonder how much current that would take, and for how
> > long?
...
> if the
> electrolyte were concentrated enough to, say, produce a current flow of
> 10 amps at 12V, it would take about 45.8 hours to reduce one pound of
> rust to iron. About 6-7 kwh with conversion losses in the battery
> charger; depending on your electrical rate, about a dollar.
>
> Then throw in about $15-20k for the swimming pool, a couple of hundred
> bucks worth of potassium hydroxide, several hundred for non-magnetic
> stainless steel wire mesh to make the positive electrode, and you're in
> business. <g>
>
> Cheers, Ken.
>
> --
> My other Triumph doesn't run, either....
Having had some experience with electrolytic rust treatment during the
course of my training as an archaeologist, I feel compelled to add a little
to this discussion. Electrolysis removes rust in two different ways. First
is electrochemical reduction of the oxidized iron back to the metallic
state. Second, the bubbles of hydrogen gas evolved at the cathode (the
object being treated) gently remove flakes of rust without damaging sounder
material. When the current is high, the mechanical removal process
dominates. At low current, reduction is more prominent. With low current
(to prevent loss of material), the time to treat an object is usually on
the order of weeks or months. (In the case of very large objects, such as
cannons, YEARS.) The reduction needs to be done outdoors or under a vent
hood because of the hydrogen evolved and the vapor from the caustic
electrolyte. There are also other reactions taking place that aid in the
removal of salt contamination, making this process ideal for material
recovered from shipwrecks. However, it is much less practical than the
tried-and-true methods of blasting and brushing for car parts.
Dan Julien
'72 TR6 CC78709U (undergoing body transplant)
Austin, Texas
djulien@mail.utexas.edu
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