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Thread: Zaj, Zamk, or iron sulphate etch Debunked !

  1. #1
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    Zaj, Zamk, or iron sulphate etch Debunked !

    Hi all

    i've done the experiment in the past... but this time i'm putting it out there...

    some of the old wootz etch recipes call for a material called iron sulphate... to etch blades with...

    i purchased some iron sulphate... technical grade
    -- mixed up a batch in distilled water..
    -- cleaned a wootz knife and placed it in the etch...... left for 1/2 an hour... no etching occured at all.....

    so much for this...... I have some other ideas that may work... but i'm not hopeful...






    next experiment i'll try heating the mixture..

    take care
    Greg

    ps.. someone call myth busters.. haha

    pss.. i know what your thinking... just add some sulphuric acid... . yes, but that is not just iron sulphate now

  2. #2
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    Excellent Greg, thank you for the great job.

    I have seen many antique blades ruined as modern etching materials were used. Thanks a lot for your findings.

    Kind regards

    Manouchehr

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    Hi Greg,
    I had a different result when I used a lump of cheap iron sulpate in distilled water. A faint pattern appeared and the surface had a beautiful golden sheen (I was keeping this a secret). No heating or anything. I just put the lump into the water, then after about an hour or so wiped it onto the sample. No heating or anything just a really nice effect
    Dr. Ann

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    thanks Manoucher
    etching wootz/poulad is a tricky business... I find all barstock respond differently to the etch..
    - there's nothing easy about wootz/poulad.... except for cutting


    Hi Ann
    i've tried this a couple times.. but failed at it...(past and present) maybe it needs an hour long etch like yours... I'll try it again

    I've been able to get dilute sulphuric acid to work... it does produce an ok etch

    have you tried making a sort of mud of it...coating the blade and heating it over a flame ?

    there must be some kind of trick to it...
    In the past, i tried with the garden variety iron sulphate.. and i thought that is what confounded my experiment...
    - but this time i've got technical grade... so now i know theres more to this story than meets the eye

    thanks for your input
    Greg

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    Hi Greg,
    I did not "etch" it for an hour, just rubbed it on with a cotton ball. It may be the trace elements in the Ferric Sulphate, or elements in the steel. I have to see if I can get the materials again and reproduce it a bit more scientifically. It was part of my finding conservation acceptable methods of bringing out the pattern. I'll look for my notes.
    Dr. Ann

  6. #6
    Quote Originally Posted by Greg T. Obach View Post
    Hi all

    i've done the experiment in the past... but this time i'm putting it out there...

    some of the old wootz etch recipes call for a material called iron sulphate... to etch blades with...

    i purchased some iron sulphate... technical grade
    -- mixed up a batch in distilled water..
    -- cleaned a wootz knife and placed it in the etch...... left for 1/2 an hour... no etching occured at all.....

    Greg - I'm digging into very old chemistry lesson memories here but isn't there a difference between 'ferric' and 'ferrous'? The oxidation state of the iron ions (try saying that fast!) and therefore their chemical/reactive properties. Iron sulphate might represent more than one modern laboratory grade compound.

    Or perhaps the old (impure) iron sulphate was merely a mildy acidic solution?

    Paul

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    Thanks Paul, you made me look up my info which will explain why I got a different result from Greg. That is what happens when I rely on my memory from work I did a few years ago.

    For what it is worth here are my notes...
    Zag, ferric sulphate, like that known in Europe as bergbutter (iron alum, also known as feather alum). The analyses by De Luynes (27) and Zschokke (28) confirm that ferric sulphate is the principle active ingredient, but they suggest that miscellaneous earthy matter rather than aluminium sulphate is the adulterant” (Smith, 1988, 22-23)

    Ferric sulphate: a salt Fe2(SO4)3 that is found in nature as the hydrated minerals coquimbite and quenstedtite and is also obtained synthetically (as by oxidation of ferrous sulfate) in the white anhydrous form and that is used chiefly in making iron alums, in pickling metals, as a mordant in dyeing, and as a coagulant in treating industrial wastes

    Ferrous Sulphide (It is what I used). (FeS2)
    A few grams of crushed fragments of ferrous sulphide was placed into a glass container along with enough spring water to cover the fragments. This was shaken and the liquid was placed on a cotton wool patch and rubbed on the blade. The blade was polished with a 1200 grit micromesh and the ferrous sulphide was reapplied. The blade was given a light finial polishing. The result was highly satisfactory. The pattern was visible. The threads were light and dark grey, as with other etchants. However the difference was in the sheen. The blade was highly reflective with a hint of a golden lustre.
    ........
    It was remembering correctly those pesky iron ion oxidation states that makes all the difference!
    If any of you smiths use this method to etch, I want a commision!
    Dr. Ann

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    Hi

    i revisited the experiment this morning...
    basically i took a wootz blade... at 600 grit..
    mixed a table spoon of iron sulphate in a glass with just abit of water to cover it...
    then swabbed the blade with the solution...
    and swabbed

    and swabbed

    after 5 minutes i notices the quench line starting to come through... ah.. this is new... it suggested that some etching is going on

    after awhile longer... I could see the whole blade beginning to darken

    - after 20 minutes of swabbing i could see an ok pattern... with purple tints here and there... hmmmm...

    thank you Ann..

    the difference in experiments... this time the concentration is very strong... i used very little water to alot of iron sulphate...
    -- and it was constantly rubbed to get the etching action to work..

    this is a safe method... nothing at all like the nitric and sulphuric acids i use....

    But... .. its a slow process... I believe it would produce better pattern the higher the grit you go...


    Iron sulphate does work... so now i will have my plate of crow..

    Greg

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    HI Greg,
    Great! That is why they are called "experiments", it is an excuse to try something new.
    My next try is pomagranate juice. Wine and tea work because the tannins deposit differently on the cementite and the ferrite and it is not a true "etch" but a surface deposit, but they do bring out the pattern (and does not damage the object).
    I want to find out what makes the "green color glittering on it" as al-beruni wrote.
    Dr. Ann

  10. #10
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    i have some experience with tannins..... i wish i could get my hands on some gallo tannates.... but instead i used some of the tannins in the wine making process...

    what i did was a prior etch in nitric or sulphuric... then rub on the tannic acid solution after...
    -- only some blades worked... and it really prefered the sulfuric etch for some reason.. ?

    -- it does go jet black on the waterings on occasion..... very neat !

    Greg

  11. #11
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    I'd like to see the difference between ferric sulfate and ferrous sulfate.

    As Paul notes:
    Greg - I'm digging into very old chemistry lesson memories here but isn't there a difference between 'ferric' and 'ferrous'? The oxidation state of the iron ions (try saying that fast!) and therefore their chemical/reactive properties. Iron sulphate might represent more than one modern laboratory grade compound.
    When we use ferric chloride as an etchant, it oxidizes (IIRC) from ferrric to ferrous as it etches, and when it is ferrous chloride, it stops etching. Maybe the same holds true for the sulfate ions...
    "Where the spirit does not work with the hand, there is no art."
    Leonardo da Vinci

    "A little science estranges men from God, but much science leads them back to Him."
    Louis Pasteur

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    Question

    That gets me to wondering ! Ferric/ferrous, sulphate/sulphide ? Or is it the iron itself ? Blood does a good job of rusting steel ,is it the iron in the hemoglobin or something else?...pH should play a big part too... If stainless steel is contaminated with iron particles , the iron rusts and the rusting then continues into the stainless steel !..That's the neat thing about science , you ask a question and may get an answer but you get 10 more questions .
    Ascertained with certainty

  13. #13
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    on this site it says that its a difference in oxidation state

    http://www.newton.dep.anl.gov/askasc.../chem00149.htm

    makes sense
    Greg

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