[AJD] washing soda

[Steve Treimer]

For electrolysis, the primary thing you need is an electrolyte to allow the charge to pass through the solution to work on the metal.  This could be as simple as table salt depending on what your goal was.
  For derusting electrolysis, baking soda would work just fine as an electrolyte, except the pH of the solution it produces when dissolved is fairly low.  Someone was correct when they said the carbonate (not the bicarbonate in baking soda) is more alkaline/basic, i.e., it generates a bath that has a higher pH.  Sodium Hydroxide (Lye) would produce an even more alkaline bath (higher pH).  The only precaution you must use is that sodium hydroxide is aggressive enough to burn if you don't treat it with respect.  It is referred to as a Strong Base in chemistry.  
   
  Why do you want a high pH solution from a strong base to do this job?  Efficiency is the correct answer, but I'll explain.  Oxygen is produced at the anode.  Hydrogen at the cathode.  If you understand how these are produced from the splitting of water, you see that how easily it is made depends on how acidic the bath is (how much H+ ion is in there for those that care).  You don't want oxygen to be made easily when doing this procedure.  It reduces your electrolysis efficiency.  So the higher the pH the better.  If I were doing it, I too would use regular old Lye and just use care with it and make sure my kids knew it was off limits.
   
  Hope it helps.
  Steve
   
  
DAVID BRUCE <davidbruce at yadtel.net> wrote:
  Not really being familiar with a 'Hot Tank' solution I risk going out on a
limb but ...
Probably the hot tank solution is basically lye (potassium hydroxide or
sodium hydroxide) in solution. If that is true, the hydroxide solutions
are "stronger" than Washing Soda (sodium carbonate or soda ash) but other
than taking the appropriate safety precautions I would think it will work
as well for the electrolytic rust removal. Now using washing soda in a
'Hot Tank' might not work as well. Just my opinion with a significant
lack of information - ymmv - and I'm sure there are others here that have
more practical experience than I do.

David
NW NC

> Possibly a dumb question,
>
> So is Soda Washing similar to a 'Hot Tank'
> solution? Or will it remove rust as well? This
> sounds like something I need to try...
>
> Chris
>



_______________________________________________
Antique-johndeere mailing list
http://www.antique-tractor.com/mailman/listinfo/antique-johndeere