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Tux Park License Plate Bracket

Discussion in 'Early Jeep Restoration and Research' started by BadGoat, Apr 2, 2020.

  1. Sep 24, 2020
    ojgrsoi

    ojgrsoi Retired 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Weatherford, TX
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    Dec 30, 2002
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    I would soak the glass in vinegar overnight. Then see what a toothbrush and toothpaste would do for a start. Glass cleans up pretty well.
     
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  2. Sep 24, 2020
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    Jan 23, 2014
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    4,220
    As far as restoring the white metal (chrome) housing, I would leave any repairs to the pits to the chrome shop. There are chrome platers that specialize in pot metal/white metal. They know how deep to grind and fill pits with their favorite rod, depending on the alloy of the light base.
    I would not try to bead blast the chrome off. You will blast the loose chrome off, but chrome is very hard. Even glass beads will erode the soft base metal away once you get through the surface plating. A chrome shop will usually remove/strip the plating by reversing the chroming process in solution tanks. I don't think the original part ever got any copper under the chrome.
    -Donny
     
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  3. Sep 25, 2020
    SoCalNickG

    SoCalNickG Member 2023 Sponsor 2022 Sponsor

    Whittier, CA.
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    The chromed light housing is zinc die cast (pot metal). It probably had four (maybe only three) layers of plating. The first (maybe first two) would be copper. In the 60's the first coat would have been cyanide based copper. This first layer is a ‘flash’ coating and protects the zinc material from the subsequent layer's chemistry. The flash copper is thin and is followed by a thicker layer of copper, next would be nickel finally followed by the chrome. The chrome layer is much thinner than the copper or the nickel. You can strip the chrome easily in muriatic acid (pool acid). It will be difficult to strip the nickel completely without a chemical stripper. Blasting is difficult to remove all of the nickel/copper on zinc die cast, without damaging the base metal further. Zinc is soft and the pits are like ice bergs. The pits are bigger and deeper than the surface ‘bump’ would indicate.

    I would be hesitant to use filler like J B Weld, or the like, because the chrome plating requires electrical conductivity. I don't know if the dried repair will conduct electricity. This type of plating (commercially) uses low voltage (6 to 12 volts) but high amperage (several thousand amps per tank) DC current. The parts to be plated are the cathode (negative charge) and the current runs from metal anodes through the plating solution.

    If the electrical current can’t reach a section of the surface that section will not receive plating.

    The way the plater would fix a part like this would be to chemically strip it down to the copper layer and apply a fresh copper flash. Then they would build up with a copper that has a faster build rate (typically acid based copper). The job then becomes a series of plating to partially fill the pits and sanding/ buffing the copper layer. You remove some of the copper from the surface, that was just plated, in order to ‘bring the bottom of the pit up’. Eventually this will give you a copper layer that you can buff and not see any pits having been filled with copper. If you build up the copper to fill the pits all at once you can end up with amore brittle copper layer. (This part of the job is similar to body work where filler is built up and sanded down, repeatedly, to achieve the smooth finish prior to paint.) Some shops will solder in the pits with lead or silver then start the copper plating/buffing cycle. Then it’s time to start the nickel plating. The majority of the brightness of chrome plated parts is from the underlying nickel. The nickel is many times thicker than the chrome. The final chrome is much thinner but more dense and hard than nickel. That’s why polished nickel will turn yellow and tarnish while chrome doesn’t.

    That was longer than I intended, sorry.
    Nick
     
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  4. Sep 25, 2020
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    From my past experience with restoring white metal/pot metal, the plater strips all plating off to the base metal. He then drills/grinds the pit to clean metal, then "solders" in filler metal using as similar of filler rod as he can to the original base metal. I have 3 different zinc alloy filler materials that I have had limited success in filling pits. One of my platers had at least 8 different alloys for filler rods.
    After the basic pit filling is completed, the plating layers are reapplied. You could not practically ever fill the depth of the pits in a zinc casting with layers of copper.
    -Donny
     
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