[HH] rust removal

[Mark Woodward]

On 04/28/2012 04:25 PM, Tom Metro wrote:
> Mark Woodward wrote:
>> ...I would use is sodium perchlorate (oxy-clean)
>> dissolved in water and a battery charger for electrolytic rust removal.
>> It was amazing, connect the electrodes, drop a part into a bucket of
>> solution, and in a day, the rust was gone.
> Neat. I hadn't heard of using electrolysis for rust removal, but it
> makes sense given that you often hear of stray current playing a role
> contributing to corrosion.
>
> It might take some digging to find a battery charger that would work for
> this. Most modern charger are now microprocessor controlled, and refuse
> to output anything unless they detect a minimum battery voltage. (But I
> do have an old-school charger with a manual mode that would work.)
It doesn't take a lot of current, but obviously the more current you can 
use the faster it will work. The resistance through the solution is what 
will control the current. The further apart the anode and cathode the 
lower the current draw on the power supply. You could increase voltage 
as well, E=I*R.
>
>> I imagine you could construct a recirculating continuous stream system
>> with a water pump and a tray big enough to catch the return solution for
>> objects bigger than can be easily submerged.
> I'm not sure that would be effective, as it doesn't sound like it is
> merely creating a solution that dissolves rust, but instead depending on
> the free flow of electrons from the rusted part to the anode.

Well, I think I might have failed to explain my thinking. Clamp one pole 
to the car and send the stream through a metal hose. It will work like a 
liquid MIG welder. :-)