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Thread: How did Remington anodizer their old Receivers

  1. #1
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    How did Remington anodizer their old Receivers

    How did Remington anodize their receivers at the factory? I'm restoring a fieldmaster 22 and have sent the receiver to an anodizer. The first attempt bought out terrible looking surface imperfections on the sides. The top looked great. The sides however looked as though the acid ate into the metal causing erosive layering. The anodizer who claims to be a firearms expert has agreed to a redo and has re-stripped and polished the receiver to a mirror finish. He says he thinks it is STILL not going to anodize properly. I feel he's missing something because Remington was able to anodize receivers at the factory. So why can't it be duplicated after market? My feeling is that maybe the receiver sides should be block sanded to a much lower grit such as 320 or 400. Possibly the buffing process digs into the metal deeper at various points thus causing the acid to etch unevenly.

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    "Possibly the buffing process digs into the metal deeper at various points thus causing the acid to etch unevenly."

    Acid? I thought they etched aluminum in basic solutions.

    My son did a beautiful job anodizing one of his aluminum-framed steam engines and it wasn't that difficult. He used blue RIT cloth dye for the coloring and it came out looking gorgeous.

    However, he buffed the parts to a pretty good shine and degreased it absolutely thoroughly before anodizing.

    Maybe he ought to patent his process.
    Last edited by 230RN; March 18th, 2012 at 07:41 AM.
    Trouble is, these jerkwads can pass dumb, self-serving, agenda-driven stupid laws much faster than we can beat them down in the courts. And they're well aware of that.

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    Y'all got me curious ---

    The most widely used anodizing specification is a U.S. military spec, MIL-A-8625, which defines three types of aluminium anodization. Type I is chromic acid anodization, Type II is sulfuric acid anodization, and Type III is sulfuric acid hardcoat anodization
    Preceding the anodization process, wrought alloys are cleaned in either a hot soak cleaner or in a solvent bath and may be etched in sodium hydroxide (normally with added sodium gluconate), ammonium bifluoride or brightened in a mix of acids. Cast alloys are normally best just cleaned due to the presence of intermetallic substances unless they are a high purity alloy such as LM0.
    Aluminium anodizing is usually performed in an acid solution which slowly dissolves the aluminium oxide. The acid action is balanced with the oxidation rate to form a coating with nanopores, 10-150 nm in diameter.[6] These pores are what allows the electrolyte solution and current to reach the aluminium substrate and continue growing the coating to greater thickness beyond what is produced by autopassivation.[7] However, these same pores will later permit air or water to reach the substrate and initiate corrosion if not sealed. They are often filled with colored dyes and/or corrosion inhibitors before sealing. Because the dye is only superficial, the underlying oxide may continue to provide corrosion protection even if minor wear and scratches may break through the dyed layer.
    A good site on the basics: http://bryanpryor.com/anodizing.php

    The three quotes above are from Wikipedia.

    My guess, and it's only that, is that in prepping the recever was not completely clean of all grease or foreign matter, and the reaction was different at that point. The acid bath has to react uniformly with the metal to produce uniform looking results.....
    Paul
    People have some respect for the complexity of technology. But almost every ignorant fool thinks he understands money and economics.

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    "and may be etched in sodium hydroxide "

    I guess that's what I was thinking of.
    Trouble is, these jerkwads can pass dumb, self-serving, agenda-driven stupid laws much faster than we can beat them down in the courts. And they're well aware of that.

  5. #5
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    As I have been told, the aluminum alloy used in military firearms is an "aircraft grade" alloy that would probably process differently from the aluminum alloys used in .22 rimfires of the 1960s. I would not try the same process on my old Marlin 60 that would refinish my son's M4; I suspect the metals are different enough even tho' they are both aluminum alloys.

    Requote:
    ...Cast alloys are normally best just cleaned due to the presence of intermetallic substances unless they are a high purity alloy ...
    Cogito me cogitare; ergo, cogito me esse.

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