• macro etchant for Ali

    From Richard Smith@21:1/5 to All on Sat Nov 12 17:37:22 2022
    Hi all
    Could you remind me.
    Macro etchant for Aluminum...
    To inspect welds on Ali.
    I think the suggestion a few months back was spray-on oven cleaner. Brands/types which work?
    Am in the UK, so would have to look for one available here.
    If anyone nominates a brand which isn't available here, I could still
    look up the overall nature of its ingredients and find the most
    similar here.
    I tried washing soda, which seemed to clean the Ali, but didn't etch
    it even steaming hot at high concentration.
    Thanks in advance,
    Rich Smith

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Sat Nov 12 17:39:55 2022
    Hi all
    Immediately written it, recalled where had made note.
    Jody at weldingtipsandtricks recommends "Easy Off" oven cleaner as his
    favoured method.
    Rich S

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to All on Sat Nov 12 16:41:33 2022
    "Richard Smith" wrote in message news:lyleogaxbh.fsf@void.com...

    Hi all
    Could you remind me.
    Macro etchant for Aluminum...
    To inspect welds on Ali.
    I think the suggestion a few months back was spray-on oven cleaner. Brands/types which work?
    Am in the UK, so would have to look for one available here.
    If anyone nominates a brand which isn't available here, I could still
    look up the overall nature of its ingredients and find the most
    similar here.
    I tried washing soda, which seemed to clean the Ali, but didn't etch
    it even steaming hot at high concentration.
    Thanks in advance,
    Rich Smith

    ----
    The active ingredient is Sodium or Potassium Hydroxide, AKA lye, alkali, caustic soda, caustic potash. Besides Aluminium they also dissolve Zinc and human flesh. They are sold as oven and drain cleaner, for home made soap,
    and to put on pretzels before baking them, to create the brown color and
    glaze. Hopefully they absorb CO2 from the air or oven flame and are
    neutralized to baking soda. https://www.npr.org/sections/thesalt/2014/08/09/338591194/for-a-proper-pretzel-crust-count-on-chemistry-and-memories

    The fizzing when they react with Aluminium is Hydrogen, in case you want to make UFO balloons which we did as pranks in college. It's nearly impossible
    to correctly estimate the size of or distance to an unidentified object in
    the sky, or on a movie screen. https://www.thepropgallery.com/media/wysiwyg/DW-TARDIS-mike1.jpg

    https://en.wikipedia.org/wiki/Exeter_incident
    I wasn't involved in that one but I've flown less ambitious Hydrogen and hot air balloons in that region. The plans for balloon sections (gores) had been published in a Boy Scout magazine. The reported erratic movements are
    typical of a marginally buoyant balloon in the turbulence around trees and buildings. The bright red light could have been road flare powder.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Sat Nov 12 21:49:22 2022
    Thanks. Will make sure NaOH is high up on the list of ingredients.
    I like the idea of being able to carry NaOH in a convenient form - as
    a spray-can.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Fri Nov 18 09:10:27 2022
    Hi all
    Just managed to etch my weld with "Drain cleaner / Drain unblocker".
    Which is NaOH.
    Couple of teaspoons of in a thin layer of water at the bottom of a
    stainless steel pan, hot.
    There is a fizzing reaction on the surface, and I repeatedly wiped it
    with a tissue wrapped around a rod.
    Gave a good etch - cross-sectional structure of weld totally clearly
    revealed. Objective achieved.
    This is with 5000-series Al-Mg alloy - very corrosion resistant.
    Rich Smith

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to All on Fri Nov 18 07:51:32 2022
    "Richard Smith" wrote in message news:lyk03swruk.fsf@void.com...

    Hi all
    Just managed to etch my weld with "Drain cleaner / Drain unblocker".
    Which is NaOH.
    Couple of teaspoons of in a thin layer of water at the bottom of a
    stainless steel pan, hot.
    There is a fizzing reaction on the surface, and I repeatedly wiped it
    with a tissue wrapped around a rod.
    Gave a good etch - cross-sectional structure of weld totally clearly
    revealed. Objective achieved.
    This is with 5000-series Al-Mg alloy - very corrosion resistant.
    Rich Smith

    -----------------

    The rule is to always add strong acid or alkali to water instead of the
    water to them, to avoid instant boiling and spattering. Wear safety glasses
    and if possible use them within reach of a sink or hose so you can wash off
    any spills. https://www.pure-chemical.com/blog/general-guidelines-safe-chemicals-laboratory/

    NaOH will absorb water and CO2 from the air if not kept sealed.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Snag@21:1/5 to Richard Smith on Thu Nov 24 16:13:49 2022
    On 11/24/2022 3:57 PM, Richard Smith wrote:
    On my own "weldsmith" website - webpage

    http://weldsmith.co.uk/tech/welding/weld_test/macro_etch/221117_alimig_macro1st.html
    "Ali MIG/GMAW 1st-ever macro-etch"

    Images of the macro.
    Quite good I venture to reckon.


    That makes me want to go out and weld something so I can cut it up
    and etch it ...
    --
    Snag
    "You can lead a dummy to facts
    but you can't make him think."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Thu Nov 24 21:57:39 2022
    On my own "weldsmith" website - webpage

    http://weldsmith.co.uk/tech/welding/weld_test/macro_etch/221117_alimig_macro1st.html
    "Ali MIG/GMAW 1st-ever macro-etch"

    Images of the macro.
    Quite good I venture to reckon.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to Richard Smith on Thu Nov 24 19:22:10 2022
    "Snag" wrote in message news:tloqas$o312$1@dont-email.me...

    On 11/24/2022 3:57 PM, Richard Smith wrote:
    On my own "weldsmith" website - webpage

    http://weldsmith.co.uk/tech/welding/weld_test/macro_etch/221117_alimig_macro1st.html
    "Ali MIG/GMAW 1st-ever macro-etch"

    Images of the macro.
    Quite good I venture to reckon.


    That makes me want to go out and weld something so I can cut it up
    and etch it ...
    Snag

    -------------------------------
    Hardening and tempering steel produce distinctive grain patterns too.

    Here is more general info on etching for analysis: https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781118960332.app4

    Don't try to buy chromic or hydrofluoric acid which are corrosive poisons,
    or picric acid which is the WW1 explosive Lyddite. Oxalic acid is in
    Barkeepers Friend cleaner. Although they are not a strong acids, it and
    citric acid wrap themselves around iron atoms to make them more soluble in water. That's why Coca Cola (and Army coffee, I found) dissolve rust.

    Nital becomes explosive if the HNO3 content exceeds 5%. It's what we used in the Materials Science course to show the grain of polished steel samples. Polishing (buffing) minimized the scratches that interfere with seeing grain boundaries. To make the small and irregular metal sample manageable it was
    cast into a plastic disk of standard size to fit the polishing machine and microscope.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bob Engelhardt@21:1/5 to Richard Smith on Fri Nov 25 08:54:28 2022
    On 11/24/2022 4:57 PM, Richard Smith wrote:
    On my own "weldsmith" website - webpage

    http://weldsmith.co.uk/tech/welding/weld_test/macro_etch/221117_alimig_macro1st.html
    "Ali MIG/GMAW 1st-ever macro-etch"

    Images of the macro.
    Quite good I venture to reckon.


    Quite good, I agree.

    A note about drain cleaner: there are other ingredients beside NaOH. I
    use NaOH as paint stripper & when I tried to substitute drain cleaner,
    those other ingredients made a proper mess. I can't say that they would
    affect your etching, but you might try pure NaOH to see. The pure stuff
    is reasonably available from soap-making supply houses.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to Richard Smith on Fri Nov 25 12:35:38 2022
    "Bob Engelhardt" wrote in message news:pO3gL.89418$kmVf.29128@fx15.iad...

    On 11/24/2022 4:57 PM, Richard Smith wrote:
    On my own "weldsmith" website - webpage

    http://weldsmith.co.uk/tech/welding/weld_test/macro_etch/221117_alimig_macro1st.html
    "Ali MIG/GMAW 1st-ever macro-etch"

    Images of the macro.
    Quite good I venture to reckon.


    Quite good, I agree.

    A note about drain cleaner: there are other ingredients beside NaOH. I
    use NaOH as paint stripper & when I tried to substitute drain cleaner,
    those other ingredients made a proper mess. I can't say that they would
    affect your etching, but you might try pure NaOH to see. The pure stuff
    is reasonably available from soap-making supply houses.

    -------------------

    I haven't seen "Red Devil" for a while, but I recently noticed "Rooto" lye
    in white plastic 1 Lb bottles at a local True Value hardware store.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Sat Nov 26 07:52:29 2022
    For any onlooker wondering "why" - why this effort, why this
    happiness...

    As seen
    Snag
    Bob Engelhardt

    "macro" (macro-etch) is a window into the internal form and structure
    of your weld.
    Cut across your weld and expose a cross-section; prepare and etch that cross-section.

    Coupled with visual inspection seeing the external surface form, you
    have a strong diagnostic tool.
    "nick-break" will inspect consistency along a long length of weld, so
    that is a valued ready test ("macro" samples one plane at random).
    "Visual", "macro" and "nick-break" take you a very long way refining a
    weld.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Sat Nov 26 07:38:21 2022
    Thanks for your treatment of the topic.
    Fantastic information about what works.
    Well-judged mention of realistic bounds - what's "no go".
    I've done this with Ali at home, but from what I know I'd grant the "off-limits" for "kitchen" etching you bring into view.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to All on Sat Nov 26 06:45:25 2022
    "Richard Smith" wrote in message news:ly7czii24i.fsf@void.com...

    For any onlooker wondering "why" - why this effort, why this
    happiness...

    As seen
    Snag
    Bob Engelhardt

    "macro" (macro-etch) is a window into the internal form and structure
    of your weld.
    Cut across your weld and expose a cross-section; prepare and etch that cross-section.

    Coupled with visual inspection seeing the external surface form, you
    have a strong diagnostic tool.
    "nick-break" will inspect consistency along a long length of weld, so
    that is a valued ready test ("macro" samples one plane at random).
    "Visual", "macro" and "nick-break" take you a very long way refining a
    weld.

    ----------------

    There are visible lines both between the parent metal and the rod, which are different alloys, and also at the apparent depth of passes within the rod alloy. Are these are crystal size/structure differences due to different cooling rates?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Sat Nov 26 18:45:10 2022
    Simple answer - don't know!
    You are reading a lot more into this than I presumed to be able to (!).

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to All on Sat Nov 26 16:55:43 2022
    "Richard Smith" wrote in message news:lyo7stwo5l.fsf@void.com...

    Simple answer - don't know!
    You are reading a lot more into this than I presumed to be able to (!).

    ----------------------

    You seem very well informed so I guessed you might know.

    https://www.mig-welding.co.uk/wiki/Macro_Etch

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Smith@21:1/5 to All on Mon Nov 28 08:10:21 2022
    Funny thing - the "steel" weld looks so incredibly similar to some of
    my own macros - for laser+MIG/GMAW-hybrid... About 3kW to 4kW of
    laser additional to MIG/GMAW (can't be bothered to look, but doubt
    ever laser+FCAW as would have had to deal with the slag when already
    difficult enough going in and out of a locked & interlocked vault to
    deal with the test-welds).
    See http://weldsmith.co.uk/big_files/thesis_fatgproj_rev111029/fatigue_perform_Tjoint.pdf
    sequential page 25 of 48 (numbered page 17) top right-hand-side two

    "Monster" penno. not in general useful as engineering design basis -
    the strength calculations - would usually be penetration / fusion to
    fillet corner.
    The cheapness of fillet welds is not just how readily done and robust
    of conditions to achieve they are, but also you are very satisfied
    with visual inspection only. You are not asking anyone to believe
    there is something complex going on deep inside the weldment which
    would need and expensive volumetric inspection test to see (typically Ultrasonic Testing). [there's no way to "pocket" money for not doing
    what you are contracted to do with fillet welds - as the external size
    you can measure at the surface dictates how much metal you must
    deposit, which forces a cost, and you cannot "trouser" money in any
    way (you could vindictively do a "not weld" by doing a machine setting
    which likely gives only "kissing contact" and weld metal there but no
    weld but that wouldn't "trouser" you any money - and that would
    show-up on mag-part, which would have you thrown off the job with no
    pay having run up expenses)]

    Anyway, I'm just looking bemused at the similarity - no suggestion of
    anything at all...

    Rich S

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jim Wilkins@21:1/5 to All on Mon Nov 28 18:16:31 2022
    "Richard Smith" wrote in message news:ly4jujo5xu.fsf@void.com...

    (you could vindictively do a "not weld" by doing a machine setting
    which likely gives only "kissing contact" and weld metal there but no
    weld but that wouldn't "trouser" you any money - and that would
    show-up on mag-part, which would have you thrown off the job with no
    pay having run up expenses)]

    ---------------------

    A sabotage trick by slave labor U-Boot hull welders was to pack most of the joint with loose welding rod and only cover it on the outsides.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)