"Electrolysis Rust Removal" - valid theory or bupkis?

Discussion in 'General Science' started by strantor, Dec 24, 2012.

  1. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    I found a tray full of tools in the garage that has been filled with water for some months or years from the looks of it. The tools are mortally rusted, but I was wondering if there might be some way to shock life back into them. I was wondering if there was something akin to electroplating that might revive them. My first google search led me to this instructable, and I thought "ok, wow, this really is 'a thing'." and I commenced to setting it up.

    He says
    I did not even question this at the time, because I was sold on the idea.

    Got it all set up, and as I was watching the first tool fizzing in the electrolyte bath, it dawned on me that this is the exact same setup that I used for electro-etching a few years back. As I recall, what is actually going on is that the current super-accelerates the oxidation process. I recalled watching a youtube video where a guy did this very same thing to intentionally add years worth of rust to a metal sculpture overnight, for artistic effect.

    So what am I doing here? Fighting rust with rust?

    Now doubtful of the process, I decided to continue, but compare the results with an un-eletrolyzed control rusted tool. The instructable says that after electrolyzing the tool, you still need to wire brush it. So, I did, and on another comparably rusted tool I only wire brushed.

    here are the results:
    Electrolysis pliers, before:
    [​IMG]

    Electrolysis pliers, after:
    [​IMG]

    Non-electrolysis pliers, only one side done for comaprison.
    [​IMG]

    So I think the non-electrolysis pliers actually look better. But they were not the exact same pliers, and may have been in better shape under the rust. I am wondering if I should even continue with this. Does it violate the laws of nature and/or common sense?

    If you google "electrolysis rust removal" you'll get tons of hits, describing how to do it and how it "works", but that is not evidence of sound science. You'll get comparable hits if you google how to make a magnetic perpetual motion motor.
     
    Last edited by a moderator: Dec 25, 2012
  2. Metalmann

    Active Member

    Dec 8, 2012
    700
    223
    You could also try a product like "Evaporust".:


    http://www.evapo-rust.com/


    I've used it on several tools, machine tools; over the years. A lot less messy. And faster. Less cleanup.

    Sometimes, you may have to run it through 2-3 times to get it done.
     
    strantor likes this.
  3. vortmax

    Member

    Oct 10, 2012
    103
    18
    The cool thing about using electrolysis in this fashion is that it is the reduction counter reaction to the oxidation process....it physically reverses the rusting process and leaves behind virgin iron.

    The issue is that when a part has rusted for a while, the layer of oxide begins to degrade and flake off. This mechanical damage cannot be undone by the electrolysis process. This is why your polished tool looks better...you physically smoothed the surface while the electrolysis just converted the rust (which is no longer a smooth surface) back into iron, leaving the same roughened surface behind.

    The benefit of using electrolysis is that it can completely kill rust in places you would be hard pressed to access with a grinder (and if you miss any rust, it will spread with a vengeance). It also can save delicate parts and features, which is why it is used to preserve and restore many recovered artifacts from ship wrecks.
     
    strantor likes this.
  4. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Yeah that is next. I usually try to put off spending money until I've exhausted all other options. I appreciate the recommendation, and I will try it. But I'm still interested in the science (or lack thereof) of the "electrolysis rust removal" method. Any idea if it is based, even loosely, on scientific fact? Or is it science fiction?
     
  5. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Ah, so there is merit to it! Good. Now I feel less retarded. A kitten dies for every minute of time I spend doing something foolish. Glad I didn't kill any kittens today.
     
  6. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Metalmann, would you be the same metalmann from hobbymachinist.com?
     
  7. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    So, I was incorrect in saying that passing current through the tool in this manner is rapid oxidation? It is actually the opposite, reduction? If so, isn't this process more akin to electroplating than electro-etching? And, if this is the same or close to electroplating, what metal is being deposited onto my tool? Metal from my sacrificial anode (chicken wire)?
     
  8. atferrari

    AAC Fanatic!

    Jan 6, 2004
    2,644
    759
    Hola strantor,

    Could you resize the pictures prior posting? Hard to read posts the way they are now.
     
  9. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    This article has a description of the chemistry involved in iron electrolysis. I'm no chemist, so I can't vouch for its accuracy.
     
  10. Metalmann

    Active Member

    Dec 8, 2012
    700
    223

    As far back as I can remember, that's the method in a nutshell.
    The first time I tried it was back in the 70s on some old hand tools.

    Somewhere on the Net, there is an explanation from one guy...who de-rusted a whole trailer frame, something like 20+ feet long.
    I think he used plywood forms, them lined them with heavy plastic film...

    Can't imagine me...trying anything that size.:eek:
     
  11. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    I have used it to de-rust some old tools (pick and axe heads, etc.) that I found in an old gold mining town. It worked great!
     
  12. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Sorry about that.

    I see Bertus resized them. Thank you Bertus.
     
  13. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Last time I just used citric acid from the food supermarket, in some hot water.

    It took the light rust off the tools quite well with no electricity needed, some of the heavier rust spots needed a bit of scrubbing with some steel wool. Citric acid is reasonably ok to put your hands in (for scrubbing purposes etc) although I tried not to get too much on my skin.

    Does the electricity really make that much difference compared to just using the hot acid? I think in both cases you're going to need scrubbing for the heavy rust spots.
     
  14. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    Acid continues to work after the rust is gone, removing iron from the object being cleaned. You have to watch and remove the object at the proper time.
    Electrolysis stops working when the rust is gone. It disassociates oxygen from iron oxides. No iron is removed that is not bound to oxygen.
    Electrolysis eventually gets into the nooks and crannies of a heavily rusted object. It will reveal etching that was done by rust, so a heavily rusted object will still wind up looking pitted and/or grooved.
     
  15. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,000
    1,512
    Another good rust remover is molasses. Yep, molasses, from a feed mill. It works by chelating the rust. http://www.homercidal.com/molasses/ All the car and tractor restorers seem to like the results.
     
    Ron H likes this.
  16. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Thant's good information thank you. :)

    But doesn't the electrolysis need to be done in acid anyway? So there would still be the same issue of leaving it in the acid too long if it is not removed and properly rinsed?

    With the citric acid I used the rust is attacked far more vigorously than the metal, so it was not an issue.
     
  17. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    I didn't do electrolysis in acid. I did it in salt water. I haven't made it all the way through the material that was linked to, but I think already I know something I didn't do right. I performed the electrolysis @ 2.5A for a few hours. That was too high current and not long enough. I'm going to try again once I finish reading the material and post back with the results.
     
  18. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    The best electrolyte, AFAIK, is washing soda (sodium carbonate). Not baking soda, washing soda. It's cheap and very available. It is not an acid, it's a base (alkaline). You need to wear gloves. If you get it on your skin, wash it off with water ASAP.
     
  19. strantor

    Thread Starter AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Funny you should mention that, as I initially tried baking soda. Didn't work, so I used salt water. Salt water is what I used to use for electro-etching, so I figured it would work as well for this electrolysis.
     
  20. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    I think the high pH of washing soda helps in the removal of grease and other contaminants, providing better access to the iron underneath.
     
    strantor likes this.
Loading...