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Some Observations of Verdigris

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    Some Observations of Verdigris

    Hello again, everyone:

    In continuing to research the subject of verdigris, I have reached a few more conclusions which I thought I might pass along. They are based on my experience.

    First, in doing lots of research in books, forums, and various online articles, and consulting with a number of collectors on the subject of verdigris, I have discovered that there is not a complete profile of knowledge about it. At best, it is a mixture of varying, often contradicting opinions about how contagious it is in a collection, how it is contracted, how it spreads, how quickly it progresses on an affected item, and how (if at all) it can be removed, prevented, and/or stabilized. There's talk of using olive oil or vineger to kill it and toothpicks for picking it off. There's others who swear that olive oil won't do a thing. Some say verdigris is an irreversible death sentence, while others report total success at permanently removing it (at least at whatever stage that it exists). The only thing I can really be sure about is that, if it does continue to develop, it will surely destroy the item which it affects, sooner or later.

    I AM IN NO WAY SAYING THAT ANYBODY IS WRONG. I would be the last to do that. I only appreciate the knowledge that everyone contributes to figuring out and hopefully someday conquering all of these wierd metal diseases. I especially appreciate the perspectives of Paul R who posted some valuable info in my last thread. If we don't at least try to learn what can be learned about these collectible cancers, as they are, then someday we (and all future collectors) won't even have anything to collect.

    My next observation about verdigris is at least hopeful to me, from my experiences, in the environment in which my collectibles occupy. Here's the facts:

    I have had the verdigris affected SA Badge I mentioned in my earlier thread for just short of three years now. Just last night I remembered that I had photographed the badge, when I first aquired it. They are high resolution digital photographs which allowed me to verify that the item did, in fact, have the verdigris at the time it was purchased. So, it did not develop it in my care. Next, the verdigris, after nearly three years, has not changed, progressed, increased, or worsened in the most minute, observable amount. In other words, it looks EXACTLY the same as it did nearly three years ago. So, in the absence of any other information I've been able to find about verdigris, I can conclude that it is indeed EXTREMELY slow in its progression, if it is, in fact, still progressing at all on my badge. Or, I can at least conclude, as a fact, that it progresses that slow (or not at all) under the environmental/humidity conditions which I provide. I can even reasonably suggest that, based on this, it may even be possible to completely arrest or stabilize the verdigris under the right environmental conditions. As far as "the right" environmental conditions, I can only claim to provide low humidity and stable temperatures. It's nothing complicated at all. However, such a simple thing, in my case, may have stopped something that some believe cannot be stopped!

    Since I can't find adequate information elsewhere about all this, I'm happy that I can use information from my own experiences to answer a little more of it. I'm not in any way minimizing the concerns over verdigris. I just thought I'd at least pass along some hopeful experiences of my own to anyone else who might be interested. If you have similar experiences with verdigris being completely stopped or stabilized, let me know. I was just previously under the impression that once verdigris has begun, it is a certain death sentence, progressing with noticeable speed, with no way to stop it. My experiences suggest otherwise. If verdigris is, in fact, progressing on even a microscpopic level, on the badge I mentioned, then I would predict that I will be long dead myself, before the badge dies of verdigris.

    As another observation, I believe that verdigris is much more common than it is even thought to be by many people. Often it's there, but there in such small amounts that it's not even noticed by most people. Most dealers don't even mention it when it's on a piece for sale. Furthermore, it only makes sense that a natural reaction of copper and bronze with the environment to produce verdigris would more than likely have occured to some extent (minute or overt) over the previous 80+ years, more or less. My guess is that there's a lot more verdigris out there than is even talked about or noticed by lots of collectors. I wouldn't be surprised if a closer inspection of anyone's collection (perhaps with a magnifying glass) doesn't reveal a few unexpected patients of the disease. The good news here is that maybe, with the proper care, they can be saved.

    Sincerely hopeful,

    Chris

    P.S. Please remember that I'm not looking to argue with anybody. I'm only offering my observations in an attempt to be helpful...
    Last edited by Stahlhelm; 12-23-2007, 11:32 PM.

    #2
    An update for anyone who cares:

    After continued, extensive research, I have still found absolutely nothing which suggests that verdigris emits anything into the air, thus making it contagious to other metals through the air. It seems that if active verdigris contacts another susceptible item, within an appropriate, supporting environment, then such contact can expedite its development on those other items. However, the bottom line here seems to be that, like most metal diseases, the appropriate higher-humidity level, etc. is first necessary to get it started, and later continue its process at all. Lack of the sufficient environment simply causes it to die (or at least become inactive), just as rust on iron, oxidation on aluminum, etc. The trick is, as usual, maintaining the proper environment to prevent it.

    In short, the right amount of H2O from humidity disolving with acetic acid, on copper, forms copper acetate, also known as verdigris. The acetic acid can simply be present in the air in varying amounts, depeding on your environment. It may seem to some that verdigris is contagious in a collection, when other items are being affected. However, if the environment supports it, the affects can be tantamount to a contagion, without it really being airborne. In the process of verdigris formation, the copper in a metal is absorbed, and copper acetate (or verdigris) is the result.

    I have also found a couple of interesting and informative articles on the subject, which address many of the collecting concerns that have been expressed previously:

    http://www.oregonknifeclub.org/Verdigris.pdf

    http://en.wikipedia.org/wiki/Acetic_acid

    The first article points out that vineger actually causes verdigris, whereas some have suggested using it as a method of removing it. Since vineger contains acetic acid, it only makes sense that vineger would just make it worse. This first article instead suggests using alcohol to remove it.

    Chris

    P.S. Some of you may wonder why I'm even concerned about this at all. However, for those of you who are interested, I just thought I'd post the information.
    Last edited by Stahlhelm; 12-27-2007, 08:02 PM.

    Comment


      #3
      Chris, Thanks for the additional research on this. It is truely confusing. I find it still a head scratcher. It's just one of those unexplainable things. I know we had tried a lot of different approches to solving the mystery in our conservation lab. Paul

      Comment


        #4
        Paul,

        Thanks for the response! I was beginning to think I was battling this verdigris all alone. Just kidding. I at least knew you were with me too.

        Yes, it's still a bit confusing to me, believe it or not. It seems that the more I learn about it, the more I wind up scratching my head too. Of course, I don't know that I'm 100% correct about everything. I certainly invite anyone to doubt me, politely disagree, present new perspectives, or anything else that promotes further discussion and thought. As they say (or as I'll say now), you can't walk on water, if you don't get out of the boat! I guess you could just say that this is just my modest attempt at walking on water in the world of conservation.

        The only way I can become even remotely comfortable with such things is to understand them, as much as possible. At least in doing that I am possibly somewhat better at controlling them as well. Otherwise, it's just back to chaos and unpleasant surprises for sure.

        Chris

        Comment


          #5
          Ren Wax as a Barrier?

          Out of curiosity, has anyone used Rennaisance Wax to fight verdigris? It seems that it would logically provide a barrier (of wax) between the affected item and its environment, thus possibly eliminating the ability of verdigris to form and/or progress. Of course, the wax would cut-off the two identified causes of verdigris--H20 and acetic acid--in an item's environment. It just only makes sense from the standpoint of what causes it.

          Has anyone out there had success using Ren Wax to fight verdigris? It's certainly worth asking.

          Chris

          Comment


            #6
            Hi chris. Yes, We have used Rennaisance Wax on a few museum items that have verdigris. It did slow down it's effect some what, but it did not stop it 100%. After a period of time (about 2 years) we saw a film that appeared on the surface it was a light greenish yellow tint. Which was a chemical reaction with the verdigris. Even though the humidity was at 40%. The verdigris still kept on attacking the metal even though we had the item stored in a small plexiglass box that was somewhat air tight. Our test showed that it was the air/humidity that was trapped inside the plexiglass box that was the culprit. This combo was the fuel that kept the verdigris working. Paul

            Comment


              #7
              Thanks 100% again, Paul! That is some serious research-based information to answer the very question I had. I will never argue with research like that, especially since it also goes right along with what I had already determined about the environmental causes of verdigris. That humidity seems to be enemy #1 here, and in most other cases of corrosion, as wel. As someone else mentioned, the popular encased environment for most practical displays doesn't help things either...

              Thanks again,

              Chris

              Comment


                #8
                Interesting thread. I didn't know anything about verdigris until I bought a KVK 2nd with swords that had it. I bought the two crosses on the left, and you can see the one on the far left has it.
                Attached Files

                Comment


                  #9
                  When the cross arrived, I knew I had to get rid of that stuff but didn't have a clue how. I ended up using mineral oil. I used a small soft paint brush and just kept working the oil around on the verdigris. It wasn't too difficult to remove once it was softened up.

                  Here is what the cross looks like now. I don't know if it will come back, but I'll watch it for sure. Also note that the swords were both bent when I got the cross. They were very easy to bend back into place. This cross has mm41 and is bronze...now my favorite KVK 2nd.
                  Ammersee
                  Attached Files

                  Comment


                    #10
                    The beautiful bronze patina will just get better...
                    Attached Files

                    Comment


                      #11
                      Ammersee:

                      Wow! Thanks for posting those excellent comparison photos and telling that great verdigris-removal success story! I really love to hear (and see) such things, because it proves that this stuff can, in fact, be dealt with effectively, if it is done so properly and early enough. This proves that it's not necessarily all gloom and doom, after all.

                      You're correct to say that you don't know if it will come back or not. However, the important thing is that you've obviously and thoroughly removed it, before it was able to do any physical damage. In your second photo, I can't even tell it was ever there, and that's not what I would have expected. Even if you have to remove it again, you surely are on top of the problem and way ahead of it too.

                      If you just keep doing that, and better yet, deprive it of those elements necessary for it's existence, then I'd say you should be fine, from what I've learned. Just don't give it enough humidity (monitor that with a hygrometer), and then even the acetic acid, if present, shouldn't be able to disolve and become corrosive.

                      Also, remember that this stuff obviously progresses so slow that you may never have to clean it off again anyway.

                      Thanks again for the great facts and photos you've added, and good luck, as well!

                      Sincerely,

                      Chris

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