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Electrically Removing Rust

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  • Electrically Removing Rust

    I remember reading a post not too long ago about removing rust by electrolysis / chemically. I can't find it.

    Can someone enlighten me please.

    JL..............

  • #2
    This is a copy of a article I found on the web years ago, I tried it and it does work.. you might find a better one using a Google search
    Rust Removal using Electrolysis
    Several years ago, and I can't recall how it happened, I came into an inexpensive and easy way to clean rust and grease, and, in some cases, paint, from your rusty cast iron and sheet metal parts. Taking advantage of common household cleaning products, items many of us have laying around the garage, kitchen or laundry room, and some science, you can clean parts from a single bolt up to an entire trailer frame through a process known as "electrolysis".
    What you need:
    A non-conducting container - a large plastic bucket works really well.
    Battery charger - big is better, however even one able to produce 6 to 10 amps should do. A student recently used my site as the basis for a school project and used a computer power supply in place of battery charger.
    Sacrificial electrodes. Concrete reinforcing rod works well (rebar) cut into lengths about 4" taller than your bucket or container. Do not use stainless steel! The results are a health hazard and illegal (more on that later)
    Arm and Hammer LAUNDRY soda, also called washing soda. (see below for details)
    Wire and/or cables for connecting electrodes together.
    Water.
    Small lengths of small chain (used to suspend the rusty parts in solution) or some other means to suspend the part to clean into the solution.

    The science behind rust removal by electrolysis.

Why you should not use stainless steel electrodes.

Electrolysis on a larger scale - cleaning a trailer frame.

Most of my Humdinger mudpump rig was cleaned using electrolysis.

Loosen that stuck piston with your soft drink?Using a plastic, or non-conductive bucket (not metal), mix a solution of 5 gallons water to 1/3 to 1/2 cup laundry soda. Mix well so all soda is dissolved. Do not try to use other salts. You won't get better results and
    _____________________________________________

    I would rather have tools that I never use, than not have a tool I need.
    Oregon Coast

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    • #3
      I just did a bunch of this. First time for me, sort of interesting...

      I used:

      a 6V/12V 6 amp battery charger
      a 5 gal plastic pail
      A two foot length of 1/2 inch dia, steel rod.
      a few lengths of black iron wire
      an assortment of odds and ends of steel (with small holes drilled in)
      a 1/2 cup or less of "Laundry Washing SODA" Accept no substitutes! ;-)

      I assesed the circumference of the plastic pail , and made a daisy chain of the assorted steel scraps linked with a length of iron wire. The idea is to go all around the bucket so the scraps can "see" the work that will be hanging in the center. A short pigtail was left to clamp the charger lead to. Keep the steel close to the bucket walls for greatest freedom to position the work. The +Anode can not touch the - cathode. (the work).

      Then the work was wired to hang from the 1/2 bar that was placed across the diameter of the bucket top. The work was inspected to make sure nothing was touching the scrap steel assembly.

      With those details of positioning accomplished, the bucket was filled with warm water. The washing soda was mixed up with water in a quart jar, and then poured into the bucket. More washing soda does no good, it's just carrying electrons, they are light ;-)

      The battery charge was connected - lead to the work, + lead to the daisy chain of scrap, and then turned on.

      The amp meter went up to about 1.5 amps for the work I was doing. It's all surface area dependent.

      I left the heavily rusted parts to work for extended hours. 8-12. Then the parts were pulled from the solution and rinsed and scrubbed. They came out looking like new forgings!

      There is a lot of smut and gunk associated with the process. Rust is voluminous.

      The work can be cleaned and evaluated over and again. No issues.

      Bubbles form over the active work. Hydrogen and oxygen are being split out from the water.
      Don't be concerned about explosions at 1-5 amp levels.

      The waste can be dumped just about anywhere ... it's not toxic or hazardous, but it does leave a mark!

      Have fun. Lots of Utube stuff on the topic.

      Comment


      • #4
        I didn't find rebars as sacrificial anodes very satisfactory. They erode rather quickly, they're time-consuming to set up and to clean, and you need a lot of them to provide sufficient effective area.

        Steel plates are much better, IMO. I find two plates six inches wide provide sufficient area for a 20 gallon container. They should be long enough to rest on the bottom and extend above the waterline so the connection can be made there.

        Iron wire can be used to hang the work and provide the electrical connection. This connection can be submerged. If you use a battery charger clip on to the wire, or rather something easier to clip onto attached to the wire, such as a nut and bolt, above the WL for convenience.
        Last edited by cameron; 07-15-2019, 06:14 PM.

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        • #5
          Best sacrificial anode I've tried so far is graphite plates (sawn from a block with carbide tipped blade in a table saw) - don't erode as far as I can tell, don't get covered in rust barnacles so no scrubbing off required.
          I cut them about a half-inch thick, three wide and a foot long, alligator clip connections on above the waterline, aim to have as much or more surface area on the graphite as the workpiece. A pair of them and a large workpiece will pull 15 - 20 amps for as long as the breaker in my big battery charger will stand it

          After getting frustrated using steel sheets and rods I tried using arc gouging rods (after etching away the copper apart from the last inch, leaving somewhere to solder on wires), worked well BUT if left in the solution they slowly dissolve - I'm not sure but I suspect they're graphite dust with a clay binder and the clay washes out leaving just dust below the waterline...

          Dave H. (the other one)
          Rules are for the obedience of fools, and the guidance of wise men.

          Holbrook Model C Number 13 lathe, Testa 2U universal mill, bikes and tools

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          • #6
            If you derust steel cathodically (the workpiece minus polarity) then hydrogen embrittlement is a risk. This can cause cracks, especially in high carbon steels such as tools, machinery parts and bolts. Deimbrittlement in an oven at 140C is not guaranteed to be affective. Do you feel lucky?

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            • #7
              Originally posted by old mart View Post
              If you derust steel cathodically (the workpiece minus polarity) then hydrogen embrittlement is a risk. This can cause cracks, especially in high carbon steels such as tools, machinery parts and bolts. Deimbrittlement in an oven at 140C is not guaranteed to be affective. Do you feel lucky?
              Don't plan on being lucky. I wouldn't use electrolysis on any high carbon or alloy steels, but mild steel and ordinary cast iron don't seem to pose a risk.

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              • #8
                Originally posted by cameron View Post
                Don't plan on being lucky. I wouldn't use electrolysis on any high carbon or alloy steels, but mild steel and ordinary cast iron don't seem to pose a risk.
                Although certainly very wrong for springs, I clean up old files with electrolysis with great success. Used it on a great many cutting blades for planes, chisels, and so on. ymmv.

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                • #9
                  OK, thanks guys for the refresher. I knew it was a simple process.

                  I have some concrete wire mesh sheets that are 6"x 6" squares, the stuff is probably 3/16" dia. wire. I could cut to fit snugly around the inside of the plastic pale as opposed to hanging rebar or metal strips. Less risk of having any shorts. How would that work??
                  The whole part would be evenly surrounded by the mesh. I also have some 2"x 4" wire fence, probably 3/32" dia wire. The galvanizing has long worn off of it, it's rusty. Which should I go with??

                  JL..............

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                  • #10
                    if you youtube Mrpete222, he has done many posts on rust removal.
                    I tried electrolysis, and find it very good.

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                    • #11
                      Originally posted by JoeLee View Post
                      OK, thanks guys for the refresher. I knew it was a simple process.

                      I have some concrete wire mesh sheets that are 6"x 6" squares, the stuff is probably 3/16" dia. wire. I could cut to fit snugly around the inside of the plastic pale as opposed to hanging rebar or metal strips. Less risk of having any shorts. How would that work??
                      The whole part would be evenly surrounded by the mesh. I also have some 2"x 4" wire fence, probably 3/32" dia wire. The galvanizing has long worn off of it, it's rusty. Which should I go with??

                      JL..............
                      It's all about AREA and in sight of the work.

                      The wire mesh has great sight lines, but might be shy on the area specification. You want at least as much anode area as cathode. More is better. do the math. Wire , not facing the work, does not count! ;-)

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                      • #12
                        If you make the workpiece the anode, oxygen is liberated which cannot cause embrittlement. Check the progress of the cleaning frequently. Try to keep the froth from the electrodes from mixing, as the combination of hydrogen and oxygen makes a much bigger bang if it ignites than hydrogen alone in air.

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                        • #13
                          Originally posted by old mart View Post
                          If you make the workpiece the anode, oxygen is liberated which cannot cause embrittlement. Check the progress of the cleaning frequently. Try to keep the froth from the electrodes from mixing, as the combination of hydrogen and oxygen makes a much bigger bang if it ignites than hydrogen alone in air.
                          That makes the workpiece the sacrificial anode. I've done that by mistake. I don't make that mistake now.

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                          • #14
                            I suppose it depends a bit on what you are de-rusting, however I find the solutions you get at the hardware store used (and reused) in a plastic bin work so well it doesn't seems worth the fuss.
                            in Toronto Ontario - where are you?

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                            • #15
                              Sightlines matter, but somewhat less than what might be expected. For example, both sides of my anode plates are heavily pitted, even though one side of each is close to and facing the side of the container. And, as far as I remember, I've never had the process fail to loosen what seem like hopelessly seized fasteners or parts seized together.

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