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_ The Black Stuff after Home-brew electrolysis rust removing.

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  • #16
    I wouldn't call myself an electrolysis hater, but I've done it enough times to know that there are other methods that work as well with less hassle.

    Evaporust and Phosphoric acid are examples of two other categories of rust removal chemistry that work very well. This is an example of a manifold in a Phosphoric acid bath for a couple of hours.

    Ed

    For just a little more, you can do it yourself!

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    • #17
      Not everywhere carries Evaporust, and typically, shipping it in from elsewhere is expensive.

      And how much Evaporust would one need to strip an entire 'camelback' drill press? I stripped the entire thing, including the column, using about $5 worth of baking soda and some electricity.





      Yes, it was at times a hassle to rig things electrically, or find a way to immerse a six-foot-long, four foot wide casting (some 2x10s and a sheet of Visqueen) but it cost only some time, I had nothing even remotely hazardous to dispose of, and the parts came out just as clean as Ed's manifold.

      One trick, noted above: Use a lower current and more time. Most people try to blast the part with More Power! and get it done in two hours. In some cases it works, but you have that black smut that has to be scrubbed off. Use a lower voltage and let it cook overnight- or even a couple of days. The smut rinses right off with plain hose water. The only part of that above footplate that needed scrubbing was down in the T-slots.

      Evaporust has it's uses, as does Phosphoric, Naval Jelly, electrolysis and vinegar. I have a gallon of vinegar out in the shop specifically for that purpose. Each has it's benefits, each has it's drawbacks.

      Doc.
      Doc's Machine. (Probably not what you expect.)

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      • #18
        JME from dozens of tractor, vehicle, and machine restos but you should never use electrolysis or chemicals on an assembly. You need to eliminate the loose crap from joints in order to work things apart, not create more loose crap to plug the joints further. Also, if there are any thin shims (there are inside every quality arbor press), you might dissolve most/all of them or even dislodge them and cause them to wedge into a joint tighter. Personally, I would simply oil the piss out of that press, heat a few key areas, and disassemble it in a normal fashion. If you want to treat the rust chemically afterward feel free, but to do so as an assembly will bite you in the butt at the worst moment possible.
        "I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow."

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        • #19
          I guess I disagree.... evaporust excels are chasing the iron oxides out of joints. Oxides are much larger than the molecular iron. I've had rusted gear sets on shafts that just fell off after ER treatment.

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          • #20
            Originally posted by Gary Paine View Post
            I'm guessing he's referring to what I call heavy rust pitting blisters. They're the kind that I scrape with a putty knife and throw the part back in the tank to finish cleaning. Of literally thousands of parts I've cleaned with electrolysis, I've never come across metal that wouldn't clean with the process and a wash under the faucet with a pad of 0000 steel wool.
            Rust removed by electrolysis results in about the same loss of dimension as mechanical cleaning. It may look a prettier matte gray and rust free but the metal once rusted is gone whether by electrolysis or wire brushing. Clean parts may look nice but that's cosmetics. Metal loss in critical places may degrade part function or safety. Yeah, I know: duh, but it needs to be mentioned if only for prespective.

            As for 'heavy spongey crust," ever clean up cast iron subjected to years of salt water or soil attack? It sometime comes away in thick flakes and sometimes tough concretions but there's no ressurecting original part dimension from either.

            I'm just saying: what ever means you use to clean up heavily rusted parts, don't get your hopes up.

            I know it's tempting to seek hands-off methods for doing what can be dirty and tedious work like restorations of heavily rusted parts. However, there is no short cut to thinking through each part as a separate promlem and applying the least injurious method for cleaning them.

            It's all too easy to toss whole families of segregated parts into skip boxes for chemical or electrolytic cleaning. OTH many a time my co-workers and I punished our backs and got cricks on our necks carefully hand cleaning delicate parts and inseparable assemblies with wire brush, center punch, scraper, scribe, Q-tip, stone, pipe cleaner, etc. Some things you can't leave to mesh baskets and vats.
            Last edited by Forrest Addy; 12-24-2014, 06:27 AM.

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            • #21
              Another item that has layers of thick "flakes" are truck brake drums. Heat and road salt etc do a number on them. It can take a couple of days to thoroughly clean those. It's hard to remove the residue entirely by electrolysis - the clean areas tend to attract most of the current. Multiple insertions and hand cleaning/washing will eventually win though.

              Cooking:



              Pass one :


              Good enough for a painted vice stand after a few more insertions and hand scrubbing:
              Last edited by lakeside53; 12-24-2014, 01:30 PM.

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              • #22
                Originally posted by Forrest Addy View Post
                Rust removed by electrolysis results in about the same loss of dimension as mechanical cleaning. It may look a prettier matte gray and rust free but the metal once rusted is gone whether by electrolysis or wire brushing. Clean parts may look nice but that's cosmetics. Metal loss in critical places may degrade part function or safety. Yeah, I know: duh, but it needs to be mentioned if only for prespective.
                No argument with the above, but the rusting process is stopped if done properly and no additional metal removed. That can't be said of: using an angle grinder and abrasive wheel or sanding disk; vigorous use of a knotted cut brush, sandblasting with silica, garnet, Black Beauty, A.O., etc. Electrolytic doesn't soften edges or cast lettering either, like overzealous wire wheeling can.

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                • #23
                  Originally posted by JRouche View Post
                  I have used electric derusting several times and love it. The black "stuff" for me comes in two varieties. Slimy, soft easily removed with a scotch bright and some soap.

                  And the hard as heck black stuff left AFTER cleaning the sludge. That stuff usually stays in place for me and primed and painted. If the hard black stuff is a lil lumpy and bumpy in texture I can usually break it down a lil with some abrasive sheets. JR
                  Wondering if there is any way to reliably PRODUCE the "hard as heck black stuff," as that sounds like it might have some promise for tool blackening. The "cold blue" chemicals don't do a robust job, and the "hot blue" process is difficult and dangerous unless you really have the proper setup.....

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                  • #24
                    Originally posted by Video Man View Post
                    Wondering if there is any way to reliably PRODUCE the "hard as heck black stuff," as that sounds like it might have some promise for tool blackening. The "cold blue" chemicals don't do a robust job, and the "hot blue" process is difficult and dangerous unless you really have the proper setup.....
                    Quenching in oil and letting the oil burn off.
                    "Patriotism is the last refuge of a scoundrel"

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