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H/D Electrolytic Rust Removal; Get it done in 2 hours!

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  • H/D Electrolytic Rust Removal; Get it done in 2 hours!

    So tonight I thought I'd try this electrolytic rust removal on an ancient and horribly rusty pipe vise. Ironically, Alistair has apparently done the same.

    I used 5 gallons of warm water with about a 1/4 lb of ordinary baking soda. Baking soda is sodium bicarbonate - NaHCO3, where washing soda is Na2CO3. Naturally washing soda works "better" since you get more dissolved ions for unit volume. Baking soda, however, will work just as well if you don't mind adding about twice as much. It was handy and it was 75 cents per lb on sale so i used that!

    Dropped my pipe vice in a tidy-cats bucket along with an old axe head that was likewise horribly rust. Didn't even bother to brush them off - they went in covered in dirt. I used 12 gauge copper wire and three pieces of 3/4 black pipe wire-brushed clean. My power source was a schumacher battery charger.

    This charger I hauled out of the dump for free on account of the fact it didn't work. Turned out the primary winding had blown a bit of copper wire. With a tiny piece of copper cut and soldered in to place, I was up and running, minus the timer. Set it for the "start" posistion initially. This puts out about 20 volts unloaded and is capable of sustaining a 200 amp current flow for about a minut before the thermal o/l trips.

    It boiled the water No i'm not talking about the fizzing, i mean it boiled the water. The electrodes and part were incredibly hot but the wires remained cool to the touch. Decided to turn it down to the 40 amp setting which is about 18 volts unloaded. The water remained at a nice steamy hot heat - just a little too hot to put your hands in - and fizzed along nicely. Came back two hours later and fished out the parts to take a peek. Low and behold, there was quite literally no rust to be found. Black, clean iron ...

    This works wonders ... i highly recommend this to anyone needing to derust! I'm pretty excited and had to share my expierence with someone Tomorrow i will post the pictures.


    Some final thoughts:

    1) Don't worry about getting a hold of lye or washing soda if your store does not carry them (like mine) - baking soda works great and odds are that you've got a couple of boxes around the house anyway. Get the old stinky one from the fridge

    2) The more power the better! Instead of leaving this go overnight on trickle, the 40 amp setting seemed to work great. The parts come out hot, but not too hot to handle and it removes rust at a prodigous rate.

    3) Keep the electrodes clean - if you have alot of rust either have lots of electrode surface area (something like a 1:2 ratio for rust to clean) or be prepared to whisk the rust off of your electrodes every hour. In my case, after an hour my current draw had decreased to about 2 amps. I cleaned the electrodes and it was off to the races, drawing about 15 amps.

    4) Note that these amp figures are from a crumby gauge on the charger!

  • #2
    I've been meaning to ask this every time this topic comes up. Does it also remove a bit of the base metal or only the rust?
    Stuart de Haro

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    • #3
      I've been meaning to ask this every time this topic comes up. Does it also remove a bit of the base metal or only the rust?
      If the part to be de-rusted is connected to the negative lead of the power supply, none of the base metal is removed.

      Orrin
      So many projects. So little time.

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      • #4
        Funny, my first experiment with this was a 5 gallon bucket in the back of my shop. Hooked it up to my dialarc 250, set at 100amps. There was a nice rolling boil going on, I walked away and started welding. Next thing I know the whole bucket was on fire.

        I have since moved the operation outside the shop into a 30 gallon plastic trash barrel. I am not sure if the electrode shorted and lit the plastic bucket on fire, or if welding slag set the hydrogen on fire. Either way, I feel a lot more comfortable with it outside!

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        • #5
          Doesn't the higher temperature run the risk of a greater amount of hydrogen embrittlement?

          In plating processes temperature is controlled to reduce the potential for hydrogen embrittlement.

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          • #6
            Electrolytic rust removal, with washing soda and TSP as the electrolyte, is a simple form of electrolytic cleaning, like is done to remove the rainbow oxides on stainless from TIG welding.

            If you read my post about nickel plating the hub of my Clausing Vari-speed sheave, anything that you nickel plate has to be absolutely, positively spotless, or the nickel will flake off.

            So I cleaned the hub this weekend with a common electrolytic cleaning solution that's been posted on rec.crafts.metalworking a couple of times by Ted Edwards:

            Electrolytic Cleaner

            Sodium Carbonate (washing soda) 75 grams/liter 10 0unces/U.S. gal.
            Sodium Hydroxide (lye)__________12.5__________1.7
            Trisodium Phosphate (TSP)_______25___________3.3
            Sodium Silicate (water-glass)_____12.5__________1.7

            Notice that's the common Web formula for electrolytic rust removal (washing soda = Na2CO3, and Tri-sodium Phosphate) plus two extra ingredients: Sodium Hydroxide (lye) and Sodium Silicate (water-glass).

            I bought 100% pure lye crystals at Ace hardware, and the Sodium Silicate I ordered online from:

            http://www.chemistrystore.com/sodium_silicate.htm

            I have no idea how the chemistry works, but the electrolytic cleaning solution works great! It's much faster than normal electrolytic rust removal, and I've also get able to take the oxides off of weld beads, so I'm thinking it's the same stuff that the stainless weld cleaning kits use.

            If you think the electrolytic rust removal is effective, try the electrolytic cleaning solution! It's two extra ingredients
            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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            • #7
              Originally posted by bob_s
              Doesn't the higher temperature run the risk of a greater amount of hydrogen embrittlement?

              In plating processes temperature is controlled to reduce the potential for hydrogen embrittlement.
              This is only an issue if the material is high carbon/alloy steel and you're gonna plate it, I think... if you're worried about it, baking the part or letting it set for a while (days) before stressing it again will help. I know that springs are baked after etching and before chrome plating to drive the hydrogen out for exactly this reason.

              Wikipedia has some useful info:

              http://en.wikipedia.org/wiki/Hydrogen_embrittlement

              - Bart
              Bart Smaalders
              http://smaalders.net/barts

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              • #8
                Interesting - yeah i know nothing about the hydrogen embrittlement issue. Most of what i de-rust isn't important enough for that to matter anyway!

                This is sweet! I got to go find some more rusty gizmos and gadgets!

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                • #9
                  Pictures!

                  Before:



                  After:


                  And



                  Vice, after painting chevy engine orange (don't mind the over-spray!):

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                  • #10
                    Are you going to post the Ebay ad like that Fastrack? Just kidding!

                    Great job!
                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                    Comment


                    • #11
                      Why not, everybody else does.

                      Lookin good Fastrack!
                      Home, down in the valley behind the Red Angus
                      Bad Decisions Make Good Stories​

                      Location: British Columbia

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                      • #12
                        Now if you could capture the hydrogen and oxygen to run your vehicle as some are claiming that would solve our energy problems.One "inventor" claims his device will run a truck 1000 miles on a gallon of H2O,claiming it can be used in propane,gasoline or diesel engines.I can understand how it might work in gasoline or propane engines but how would a diesel be handled?

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                        • #13
                          LOL - yeah ... when you consider the energy required to break water into O2 and H2 and then the energy released when hydrogen is combusted with oxygen, well suffice it to say that it would have to be a very very small truck to go for a 1000 miles. Or maybe 1000 miles downhill...

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                          • #14
                            Originally posted by lazlo
                            So I cleaned the hub this weekend with a common electrolytic cleaning solution that's been posted on rec.crafts.metalworking a couple of times by Ted Edwards
                            lazlo, are you using that solution with an electric charge, or just soaking the parts in it? It isn't clear to me from your post which way you are doing.

                            You can nickel-plate with electricity, or you can nickel-plate with "electroless nickel" in a pure chemical bath. Is your solution "electroless rust removal?"

                            cheers,
                            Michael

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                            • #15
                              You know I can't recall if I ever posted to this forum before. Been rather active on the PM and chaski site for a while now. So a big hello to all just in case

                              Well I have to say that this process was one of the best I've seen and tried in years! I don't know why or how I missed this one

                              I took an old large Bridgeport vice apart, degreased it and proceeded to run the process for about an hour. I took a few pics to show how well it works. After that I put it back in the bath and ran the entire night through to remove anything that was left and more of the old paint as well. I uploaded them here on my site: http://www.metalmelter.com/
                              I'd place them here but there a bit large and I'd have to re-size them all.
                              Next time ...

                              Last night I pickled the parts on phosphoric acid to give them a nice surface treatment and backed them in the oven for about 3 hours. I'll load those pictures tonight.
                              "To invent you need a good imagination and a pile of junk" Thomas Edison

                              Better to have tools you don't need than to need tools you don't have

                              73's KB3BFR

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