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Black Zinc Coatings

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  • Black Zinc Coatings

    I am wanting to "plate" all the nuts, bolts, washers, etc. off my '53 Jaguar XK120 DHC in Black Zinc. I have talked to the local platers about this process, they use a large tumbling drum, which I'm not real keen on as small items can fall out of the gaps in the drum.. Not a problem on a Ford, but a big problem on a fifty year old Jaguar as the parts are made from "Unobtainium"!
    The plater and I talked about wiring the small pieces together, this should eliminate the loss factor.. but I'm still nervous.
    Having done business with Caswell Inc. in the past, I checked my "Complete Plating Manual" (Ver 2) for Zinc Plating and Black Chromate. Then I checked the website and found that the Zinc Crystals aren't available.. My option is "Copy Cad" and a Blackening dip..
    Given that I have about a hundred pounds of nuts, bolts, washers and some small parts that I want in Black Zinc, and I printed out the Excel File "Surface Area Chart for Hex Head Bolts", I was floored to find that four 5/16" x 1 3/4" bolts equal 11.37".. The Copy Cad Plating Kit can only plate 12 sq inches at a time.
    Now the Question:
    What size tank/bucket/pond would be needed to do a "serious" amount of pieces (I'm not wanting to make a career of plating these nuts and bolts!)?
    How many Anodes?
    At how much voltage/amperage?
    I'm not wanting to "experiment" with these valuable Jaguar parts.
    Cost is a factor.. The local plating shop does up to fifty pounds for $40.
    Convenience is a factor, as I must sandblast ALL the nuts, bolts and small parts in a short time before delivering they to the plater.. I could do "batches" at my own pace.
    Additionally, I would like to hear from those who have serious experience using the Copy Cad and Blackener in plating a significant quantity (excess of fifty pounds) of nuts and bolts to learn about the ease of plating, quality of the plating, and exactly how much a "kit" would cover.

  • #2
    Black Zin Coatings

    Sorry, but I can't answer your specific queries, as I am in the same situation myself. But where does one find this "Surface Area Chart for Hex Head Bolts" spreadsheet? I could use that right now.


    • #3
      Re: Black Zin Coatings

      Originally posted by sccc
      But where does one find this "Surface Area Chart for Hex Head Bolts" spreadsheet? I could use that right now.
      I found it in "Rainer Muller's Chrome System" report on one of Caswell's webpages.. I had to do a "Search" (upper left corner) for "Excel Files" to find it again.. The link is:
      Hopefully this will open the page for you..
      Scroll down about halfway and look for the highlighted words:
      "Surface Area.xls" and "Washer Area.xls".
      The info will surprise you.. I was shocked to see how much surface area there is on a simple bolt.. the threads account for the "unusual" large size..
      Hope this helps.


      • #4
        Copy Cad IS a ZInc plating system. It will give you a professional finish on the parts you mentioned.
        There is also a new zinc blackener available. See the webpage for details. If you get stuck, email us. The V2 manual is VERY out of date.
        Mike Caswell
        Caswell Inc
        Need Support? Visit our online support section at


        • #5
          Black Zinc Coatings

          Charles, thanks! I got them downloaded. Strangely, I had tried to search on "Surface area" and came up empty. Never thought to try "Excel files".

          After reading your original post, I measured a bolt for myself, and sure enough, they have a lot more surface area than one would guess just by looking. A 1/2" shoulder bolt 2" long is almost 2" in circumference as well! at 4 sq." each, I would be at it for weeks, so I decided a hefty power supply is in order.

          BTW, the little wall-wart power brick supplied w/the kit is a joke. Using a 2x3" piece of mild steel to initially purge the copy cad mixture, I got nothing from the system. No fizzing of the mixture, and no plating. So I hooked up the voltmeter, and found that having 12 sq." submerged in the mixture would draw the voltage down to 0.45v. I gradually raised the test piece out of the mixture, and watched as the voltage increased. When it reached anout 0.9v, the fizzing began in ernest, and reached a moderate level at about 1v. By this time there was only 1 sq." of material left in the mixture. I held it there for 10 minutes, and it did plate nicely, but clearly this wall wart is inadequate to the task.