Welcome to the ABA! Bell Talk Forums Repair, Restoration, Parts, Cleaning church bell patina vs bronze disease

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    • #11215
      Patricia13
      Member

      Hi. I’m new to your site. I’ve agreed to clean and restore a large church bell that is at ground level in front of our church. The bell was cast in West Troy, NY in 1884 and appears to have been cleaned in some fashion at some time. The bottom 4 or 5 inches all around is a medium bluish color with a few dark areas showing through here and there. The top of the bell is approximately the same color but the greater part of the bell from the top down is a pale bluish color, almost white. It can be easily flaked off with your fingernail. I don’t really know anything about bells and I can’t find too much on the internet. I need to know if this is natural patina and if so, how to clean it and protect it. If it is really bronze disease, I need to know how to remove the corrosion and prevent further deterioration. There is a pinkish cast to the color in a few places which I think might mean it was not cleaned properly in the past. The bell itself appears to be in good shape and the lettering does not appear to have any deterioration or wear. Can anyone give me some guidelines to determine whether this is patina or corrosion? It is not green or patchy like the photos I’ve seen online. The light part in the middle is almost a solid color and doesn’t seem to have much if any pitting.

    • #14843
      hjlong3
      Participant

      If you can flake the coating off with your finger nail, this is more than a Patina. Patina is a chemical reaction with the bronze that provides a protective coating. It is usually an oxide of the copper and tin in the bronze. If the coating flakes off, the chemical reaction went much deeper than the bell surfance and has damaged the bell with deeper pitting. The bell may have been subjected to an acid bath or repeated exposure to acid rain. Sulfuric acid reacts with the copper to cause a blue Copper Sulfate. It will react with the nickel in the bell to cause a green salt Nickel Sulfate. Some salts of copper are rich green in color (Malachite Green). Perhaps the bell was painted and the flaking is from the paint. In any event, if it flakes, it cannot be restored to its natural bronze state without an expensive electrolytic process. It should be removed with a detergeant, water, and a bronze wire brush. Some use vinegar and salt with the brush.
      Harry Long, MD

    • #14844
      Patricia13
      Member

      Thanks for the information, Harry. You confirmed what I was most afraid of. This is not normal patina. The possibility that the bell had been painted hadn’t occurred to me but the metal parts holding the bell obviously were so you make a good point. Thanks again.

    • #14845
      Towerguy
      Member

      I realize this is an old thread, but I’m new here so I have some catching up to do!
      Sounds like someone painted the bell, bronze does not flake off. If you have not done anything with the bell as of yet you should get it sand-blasted with a glass bead media. This will take the bell back to its original state. Bronze patina is not bad for the bell and will not damage it whatsoever. Patina is just the copper oxidising. Bronze will patina untill it is sealed from the open air, preventing any more oxygen from getting to the metal.

      Here is a picture of a bell that has been sand blasted.

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