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Benefits of Electrolytic Etching

  • 1.  Benefits of Electrolytic Etching

    Houston Admin
    Posted 5 days ago
    ​I am considering investing in an electrolytic etching setup for my laboratory but, due to the cost, I need to make a business case. What do you feel are the real strengths of this method as opposed to standard etching? Obviously it depends on what you're trying to do but what materials, phases, etc. do you use it for to accomplish something you cannot accomplish otherwise?

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    Sean Piper
    Product / Process Metallurgist
    Ellwood Texas Forge Houston
    Houston TX
    773-524-8985
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  • 2.  RE: Benefits of Electrolytic Etching

    Posted 5 days ago
    Sean,

    I have an old one from Buelher in my laboratory and its function very well, I used mostly for stainless steel like AISI 304, 316, 316-L.

    Also to do an electrolythic reduction I used it (cleaning old metals pieces).

    Its an old one but its a noble artifact, I don't know if the buelher company still markets it.

    Hope the info serves.

    Regards,

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    [Patricia Silvana] [Carrizo]
    [Ms.]
    [Chemical Engineer]
    [Archaeometallurgy Area - UTN FRM]
    [Mendoza] [Argentina]
    [+542615577229]
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  • 3.  RE: Benefits of Electrolytic Etching

    Posted 5 days ago
    If I recall, we did have a dedicated etching setup but when we had a need to try electrolytic cleaning on something much larger than a met mount we ended up buying a power supply that may have been intended for plating.  I'm sure that it was a lot more amps.  Anyway it depends on how much you intend to do.  Putting a lot of engineering time into business cases for met lab processes isn't terribly worthwhile unless it's going to be something that is a slam dunk on productivity, since it costs you $1000/day on the engineering time to prepare the business case.

    Instead make the case with reduction of hazardous wastes collection and treatment costs, or on a basis that the quality / outcome needed isn't available under the non-electrolytic process currently in use, if that is true.





  • 4.  RE: Benefits of Electrolytic Etching

    Southern Connecticut Admin
    Posted 4 days ago
    I'm not sure how much of a investment you need.  Most of us have a DC power supply like a Mastech HY3600D, which cost about $200, and various wires and fairly inert electrodes.  I use an IN625 bolt.

    10% oxalic acid is my go to first etchant when I do not know what will work.

    Tom Doggart

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    Tom Doggart
    Nomad Metallurgy LLC
    Niantic CT
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  • 5.  RE: Benefits of Electrolytic Etching

    Posted 4 days ago
    Hi Sean, 

    We are currently using a MoviPol-5 electro polisher for various materials. The polisher helps create a near finish spot for etching and reduces time by alot vs mounting/polishing a specimen. Also,  in a business case the polisher can save the company a forging rather than sacrificing a piece. Cons would include not always having a very clear microstructure but that can always vary dependent on more than one variable i.e forging process, etchant used, atmosphere. 

    -Elvin

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    Elvin Gonzaga
    Quality Technician
    Charles E. Larson & Sons
    Chicago IL
    773-289-3138
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  • 6.  RE: Benefits of Electrolytic Etching

    Posted 4 days ago
    Most etching tasks can be accomplished without electrolytic etching, but there are a few exceptions. Electrolytic etching in oxalic acid to detect sensitization to intergranular corrosion for austenitic stainless steels is one case. Etching platinum alloys and color anodizing aluminum are other examples. So you do really have to make a case for what materials and circumstances you need to be prepared for.

    That said, an electrolytic etching setup can be pretty inexpensive. A DC power supply, a piece of stainless steel for the cathode, and some wires are all you really need to start etching. If you're creative and only going to use electrolytic etching once in a while, you can probably get by for not much more than $100.

    ________________________________________
    Larry D. Hanke, PE
    Materials Evaluation and Engineering, Inc.

    Sent from mobile device. Please excuse brevity and typos.





  • 7.  RE: Benefits of Electrolytic Etching

    Posted 4 days ago
    As Buehler sell these, I'll keep it to the point :)

    Most people use electrolytic methods for either (1) electropolishing (2) electroetching or (3) anodizing.
    The reason for (1) is for materials that are extremely difficult to polish mechanically, where there is time saving or when combined with (2) - so for titanium this can be valuable as you can polish and etch a sample, on a combined unit, in less than 2 minutes (mechanical approach with chemical etch ~10-15min depending on alloy)

    The reason for (2) is most often for use with materials that are highly resistant to chemicals, such as stainless steel and nickel alloys.  It can also be due to the relatively low hazard***, speed or reproducibility

    (3) is very typical for aluminum alloys and can provide excellent information on grain size, shape, orientation as well as segregation

    ***it is true that the core principle of electrolytic polishing and etching is a power supply and appropriate connections to make the circuit.  There are two key reasons for buying dedicated equipment.  The first is that some electrolytes are hazardous, especially when they get warm.  The dedicated equipment limits current, and also monitors temperature to ensure that unsafe conditions cannot occur.  The second reason is reproducibility.  The process requires control of current density, and often movement of the electrolyte, to get consistent and even results.  Dedicated equipment makes getting reproducible results much, much easier.

    Hope that helps!

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    Michael Keeble
    Buehler a Division of ITW
    Lake Bluff IL
    (847) 393-3645
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  • 8.  RE: Benefits of Electrolytic Etching

    Posted 3 days ago
    I agree with Tom and Larry. Depending on what you're etching you can get by with a pretty cheap unit. I bought a 30V power supply on Amazon for ~$85 and it has done all I've asked of it. I've etched various stainless steels (304, 316, 17-4) with it as well as Cobalt alloys. Hope this helps!

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    Adam Miller
    Materials Engineer
    Urschel Laboratories
    Chesterton IN
    21946448114277
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  • 9.  RE: Benefits of Electrolytic Etching

    Southern Connecticut Admin
    Posted 3 days ago
    The one I bought was new on Amazon for ~ $200.


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    Tom Doggart
    Nomad Metallurgy LLC
    Niantic CT
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  • 10.  RE: Benefits of Electrolytic Etching

    Posted 3 days ago
    Hi Adam,
    Could you share details on the model/brand that you are using? I wanted to check the specs to see if an equivalent model would be available in India as I have a similar requirement of etching SS 304/316. Thanks.

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    Gopal Kidao
    Madras Metallurgical Services
    Chennai, India
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  • 11.  RE: Benefits of Electrolytic Etching

    Posted 16 hours ago
    Years ago when I was a struggling-just-out-of-college-no-money type engineer, I would use a 12V lantern battery. Back then, you could go to a junkyard, and the connectors used on an automobiles windshield wipers were made from stainless steel and the junkyard would let me take them with the 12V wires for free. So I had an electrolytic etching set-up for about $20.00, that included battery, oxalic acid, and beaker. Worked perfectly well for etching stainless steel mounts as you describe above. For etching metallurgical mounts in oxalic acid you don't need a lot of sophistication. Now, if you want to get into more advanced techniques as some have described above, then you will need a more controllable power supply. But if all you want to do is etch some 304/316 mounts in oxalic acid, you can do that quite easily and cheaply. 

    dj

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    David Jones
    Senior Principal Materials Engineer
    Stryker Orthopeadics
    Mahwah NJ
    (914) 469-2958
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