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  • Spring snapped during electrolysis?

    Hi folks,

    Picked up this pair of German made circlip pliers this morning at a car boot sale.

    They were covered in surface rust and I wanted to preserve the engravings so I popped them in my electrolysis tank at 400ma 10v for about 4 hours.

    When I pulled them out one of the steel springs that force the handles open had snapped clean off. It was fine beforehand.

    I'm determined not to be the guy who broke these after they've probably been around for 50 years, so I'm going to fix them.

    Couple of questions arose as a result!

    1- What caused this? The rust was definitely just surface rust. I'm intrigued and presume it's something to do with the electrolysis.

    2- Can I just use any steel to replace it? A strip of stainless bent to the right radius?

    3- The two springs are riveted to the handle with a type of domed rivet. How do I go about removing the broken one, and how do I replace it?



    Cheers,
    Rich

  • #2
    here is a cut and paste from http://www.htpaa.org.au/article-electro.php

    Hydrogen Embrittlement of Steel - A Cautionary Note
    Atoms of hydrogen absorbed by steel are known to enter the lattice of iron atoms and prevent the layers from sliding past each other easily. This causes the steel to become more brittle and liable to crack. The absorption of hydrogen by steel is a familiar problem in industry which arises during steel refining, heat treatment, acid pickling or electro-plating. It can also happen as a result of simple corrosion. The standard remedy is to bake the objects in ovens to drive out the absorbed hydrogen (200°C for four hours would be a typical regime in industry). The simple passage of time is also known to cause loss of hydrogen from steel. Hydrogen embrittlement may occur to some extent during electrolytic de-rusting. This may be a cause for concern with saws or other edge tools. It might be wise to wait a while before setting saw teeth after prolonged, electrolytic de-rusting. Alternatively, baking the tool in the oven for hour or so at about 150°C (300° F) should remove absorbed hydrogen. Note that this baking temperatures is low enough to leave the temper of most steels unaffected. Since hydrogen embrittlement is reversible, it should not cause too much anxiety. I believe that the advantages offered by electrolytic de-rusting justify wider experimentation by tool collectors. As more experience is gained clearer knowledge of its advantages and disadvantages will emerge.



    Are the rivets in a through hole? if so drill them out. You may have to turn new ones and press them in. Even if not through hole, you may have to do it that way as i doubt you drill the other way with the opposing handle.

    you will need spring steel for new spring, regular steel won't work. You will need buy it annealed to drill and bend or anneal it yourself. Afterward, harden and temper it to make it a spring again (sounds worse than it is, it's not that difficult)
    Last edited by Mcgyver; 09-23-2012, 04:03 PM.
    in Toronto Ontario - where are you?

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    • #3
      As Mcgyver says, hydrogen embrittlement.

      If you are electrolytically cleaning or acid cleaning any thin, hardened, steel part, make sure it isn't under any stress during the process and bake it afterwards. Before I learned that lesson, I was shocked to find that the 20gauge piano wire I was using as hooks to hold parts in a phosphoric acid dip all broke after half an hour's use!
      Location- Rugby, Warwickshire. UK

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      • #4
        Originally posted by Mcgyver View Post
        you will need spring steel for new spring, regular steel won't work. You will need buy it annealed to drill and bend or anneal it yourself. Afterward, harden and temper it to make it a spring again (sounds worse than it is, it's not that difficult)
        If you have any steel strapping such as that used to band items to a pallet that will make good springs in many cases.

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        • #5
          if this embrittlement is the case ..then you may snap the prongs on the end of the tool the first time you use it !

          all the best.markj

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          • #6
            NONSENSE........

            Hydrogen embrittlement may occur to some degree, although I have never noticed any resulting fragility issues with phosphoric acid rust removal, which would have similar hydrogen problems....

            The ACTUAL problem is apparently a form of stress corrosion, where the metal is preferentially eaten away where stressed... until the remaining material breaks. It is a problem with BOTH electrolysis and phosphoric acid. It can take the form of selective surface removal in case hardened metal, breakage of springs, etc.

            You CAN often actually de-rust the springs, but they must be non-stressed when treated. I don't risk it, I remove all springs etc and limit the total time in the acid to no more than an hour. (I gave up on electrolysis, too much hassle, same problems, zero advantage in my experience).

            Your rivets may be part of the handle, or they may be "drive screws" which can be pulled out.
            CNC machines only go through the motions.

            Ideas expressed may be mine, or from anyone else in the universe.
            Not responsible for clerical errors. Or those made by lay people either.
            Number formats and units may be chosen at random depending on what day it is.
            I reserve the right to use a number system with any integer base without prior notice.
            Generalizations are understood to be "often" true, but not true in every case.

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            • #7
              Thy could be held by drive screws, you should be able to grind two small flats on the head and twist it out.
              http://www.mcmaster.com/#drive-screws/=jfbo9r
              Mike
              Brandon MI
              2003 MINI Cooper S JCW#249
              1971 Opel GT
              1985 Ford 3910LP

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              • #8
                Originally posted by J Tiers View Post
                NONSENSE........

                Hydrogen embrittlement may occur to some degree, although I have never noticed any resulting fragility issues with phosphoric acid rust removal, which would have similar hydrogen problems....

                The ACTUAL problem is apparently a form of stress corrosion, where the metal is preferentially eaten away where stressed... until the remaining material breaks. It is a problem with BOTH electrolysis and phosphoric acid. It can take the form of selective surface removal in case hardened metal, breakage of springs, etc.

                {snip}
                Plus, the most highly stressed part of the spring material will be the surface, which is where the surface rust was, giving sites for further corrosion/erosion to happen

                50 years life from a spring - it can't owe you much now

                Richard

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