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  1. #1
    Mustafa Umut Sarac's Avatar
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    LTM Body Finish Technology

    I am interested in about learning Leica Tread Mount or FED 1 Body Finish technology. I think acid could be used to finish the bare aluminum in to warm touch pored finish. I want to finish my aluminum - not marine grade - parts to same finish.
    Or was material brass and electroplated with a chemical ? Or is it chrome or nickel finish ? I am talking about top part which portholes etc. belongs .

    Umut

  2. #2
    Paul Goutiere's Avatar
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    To make a nice patina mat finish to aluminum you can use what we call "Lye" or sodium hydroxide (NaOH, also known as 'caustic soda') or "Draino". Mix with a generous amount of water, clean the aluminum well and immerse in the solution. Rinse with lots of water.

    BE VERY CAREFUL WITH THE STUFF. IT WILL BURN HOLES IN ALUMINUM, EVERYTHING ELSE AND YOU. USE RUBBER GLOVES, MASK ETC.

    I don't know what will make the same patina on brass.

  3. #3

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    The process is called anodizing

    See http://en.wikipedia.org/wiki/Anodizi...ized_aluminium

  4. #4
    lxdude's Avatar
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    Quote Originally Posted by Prof_Pixel View Post
    The process is called anodizing See http://en.wikipedia.org/wiki/Anodizi...ized_aluminium
    Another method is alodyne (chromic acid), which applied as a liquid, will give a corrosion resistant oxidation finish.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  5. #5

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    After world war ii british intelligence -- james bond? -- visited Leica and wrote a complete description in some detail of the manufacturing process underway. It includes a description of how they got that specific finish which, I have to say, I do not think they successfully duplicate today. You can find the whole thing here:

    http://www.angelfire.com/biz/Leica/page26.html

    Specifics of the satin finish are:

    25. The satin-chrome finish on external metal parts was

    obtained by the following process:-

    26. Sandblast, hot cleaner without current, cold cleaner

    with current, warm rinse, followed by cold rinse, hydrochloric

    dip, copper flash, cold rinse, sulphuric dip, cold rinse, bright

    nickel-plate, warm rinse, hydrochloric dip, bright chrome,

    drag-out rinse, cold rinse, hot rinse, and dry.

    27. All articles were jigged on racks and the racks were

    screened to obviate side-throw.

    28. The bright nickel tank was approximately 6' x 2' x 21/2',

    six depolarised anodes being employed. The volt-meter and

    ammeter on the resistance control board were all moving

    coil pattern and the tank was worked at 2 volts, 25 amps. No

    agitation of the electrolite was employed.

    29. The chrome tank was approximately 4' x 2' x 21/2', twenty-

    eight strip anti-monial lead anodes being employed. Moving

    coil volt and ammeters were also fitted in the resistance board

    and the tank was worked at 51/2 volts, 300 amps.

    30. It was particularly noted that the time allowed for a

    satisfactory chrome deposit was exactly three minutes. All the

    plating equipment was spotlessly clean.

  6. #6
    lxdude's Avatar
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    Quote Originally Posted by Mustafa Umut Sarac View Post
    . Or was material brass and electroplated with a chemical ? Or is it chrome or nickel finish ? I am talking about top part which portholes etc. belongs .
    I don't know for sure, but I would suppose that the Leica top plates of that time were made of brass, and chrome or nickel plated. EDIT: after reading the preceding post, that appears to simply be a 3-stage chrome plating process. Color of the finish will be different than with direct chrome-on-brass plating, because of the layer of nickel beneath the chrome.
    Last edited by lxdude; 09-16-2012 at 10:16 PM. Click to view previous post history.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  7. #7

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    and i love this about assembling the shutter:


    The main design of the shutter is in no way basically

    changed; only slight modification of various components to

    suit the new assembly. In the assembly of the shutter fast-

    range escapement one component after another was tried till one

    was found that worked in a fairly satisfactory manner and then

    various minor alterations were made to it by filing, and in

    some cases, a light tap with a small watch-makers hammer. The

    skill of the operators was undoubtedly the chief asset in the

    efficient assembling of this shutter.

  8. #8
    Pioneer's Avatar
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    And still my Leica IIIc has chrome peeling off!

  9. #9

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    Quote Originally Posted by Pioneer View Post
    And still my Leica IIIc has chrome peeling off!
    after 60-plus years, I'm peeling too.

    but it still works, right?

  10. #10
    lxdude's Avatar
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    Quote Originally Posted by Pioneer View Post
    And still my Leica IIIc has chrome peeling off!
    A funny thing about plating: usually the 3-layer copper/nickel/chromium process will have better adhesion. But on brass, the chrome will adhere well by itself, and its thinness will keep it from flaking off, especially on a satin finish. The thicker finish behaves similarly to paint, in that once it starts to come off, it can peel off. The direct plating is not thick enough to peel.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

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