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Electrolysis rust removal ? Answered

Does anyone know anything about Electrolysis rust removal. I tried it today on an old drill bit as an experiment and it worked quite well but I was wondering how I could improve my system. I was wondering how the voltage, amperage and surface area of the anode affect the time taken and the quality of the part. Also is there anything else that Effects ( or Affects )  either of these these. I used 2 litres of water and 2 table spoons of soda crystals with a 5 volt 16 amp supply. When I perfect my method I will clean up a very old and rusty Lister D.


I'd strongly suggest that you research the topic outside of instructables. Real experts have written a myriad of articles on the subject. Instructables folk are more often than not self-taught hackers, not experts.

Sorry, this is a bit of a siderail. I have found it quite easy to remove rust by using phosphoric acid. This leaves an black iron phosphate coating on the part. In fact, you can also add some zinc oxide or manganese oxide to the acid to give a parkerized finish that is more durable. Just make sure to wash, dry, and coat the parts in a penetrating oil right after. Heat speeds up the reaction. If you don't have a heated bath big enough, you can shoot the part with a heat gun while wiping it with the solution.

If the parts are really bad, you may want to use muriatic acid to initially remove the rust. This is very fast. But the chloride salts leftover will absolutely make the iron rust, again, untreated. You need to follow a muriatic acid batch with a dunk in phosphoric acid (or zinc/manganese phosphate for a parkerized finish).

Oh, BTW. Any of those three phosphate finishes make an excellent primer, if you want to paint. Paint right away, don't do the penetrating oil thing.

Also, if you are doing parts that must remain in tight tolerances, do not use manganese phosphate. That is the thickest of the coatings. In fact, you can use it to build up a part, slightly. The iron and zinc phosphate coatings are very thin and don't adversely affect tight tolerances. If a little tight, the coating will just wear away.

There is a mnemonic for "affect" and "effect".  The word "affect" is a verb, an action word, and both (a)ffect and (a)ction start with the letter 'a". 

So the details of your electrolysis setup do affect (verb) how the rust removal proceeds, and using the correct setup will help you get the effect (noun) you want.

Now that we've got the grammar taken care of, the usual recipe for electrolytic rust removal is an old-school (meaning unregulated, not microprocessor controlled) 12 volt battery charger, plus a bucket of water with some amount of sodium carbonate (aka Na2CO3, aka "washing soda") dissolved in it, plus one or more pieces of unpainted, uncoated, scrap steel to serve as the anode(s). 

Of the 'ibles I noticed in the related panel on the right ----------------->
I think this one,
is the best one.

An excellent effective explanation.

The way I have applied these two words to electronics is ;
  • The causing action is the  Affect ... That voltage is ionizing (ie affecting) the air.
  • The result of the action is the Effect ... The air was effected (ionized) by the voltage

Yeah. That was a good explanation for "affect" and "effect", although I don't think I did a very good job explaining the best  way to remove rust using electrolysis.  How to choose a power supply, how to control (or leave uncontrolled) the electric current which flows, or how much (how concentrated) of what kind of electrolyte to use, or how to geometrically arrange the part and the anodes... I mean stuff like that is probably what Monty, the OP, actually wants to know about.

There are several instructables on the topic. Look them up.