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Replies: 15 / Views: 1,690 |
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Pillar of the Community
United States
1549 Posts |
Who would like to write the words to go with this photo? I know there will be one of you who appreciates what was lost here. 
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Pillar of the Community
United States
1316 Posts |
dougsmit,
Wow that horrible, I'm sure you tried everything in your power, this could happen to any of us, sorry to see this......
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Pillar of the Community
United States
1315 Posts |
This reminds me of a post that Sap put up about a year ago and discussed the fact that sometimes the detail on a coin is preserved only by the patina, and that the underlying metal is fragile and can disappear when the patina is removed.
A soak in olive oil and then some renwax may at least restore the color, maybe.
Edited by Doucet 06/25/2012 8:43 pm
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Valued Member
United States
168 Posts |
Wow that's too bad. This is one of the reasons why I try to avoid bronze and copper coinage. The noble metals are resistant to oxidation.
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Pillar of the Community
United States
4981 Posts |
darn....i don't know the coin..but that is scary... Sometimes a picture is worth a thousand words, how about this one..  sorry ds! what is the best way to prevent this? vigilance? dehumidifier? drying the crap out of the coins? wax after drying? all of the above?
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Valued Member
United States
168 Posts |
From a chemistry perspective, the worst thing you could do is touch bronze coins with your bare hands! The chloride ions from the salt on your skin react with the copper ions in the bronze to form cuprous chlorides. When exposed to moist air, the cuprous chlorides are hydrolyzed to form hydrochloric acid and basic cupric chloride. The hydrochloric acid then reacts with uncoroded copper metal to form more cuprous chlorides. This reaction will continue until no metal remains. In summery, don't touch bronze or copper coins with un-gloved hands.
Edited by w00zi 06/25/2012 9:52 pm
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Valued Member
United States
422 Posts |
Old age is a curse! I know first hand.  Some of your coins... you can't save. Pity. 
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Pillar of the Community
United States
4981 Posts |
interesting woozi, I knew the moisture bad part and knew chlorides (or similar something or others) is tap water was bad (soak in distilled), but didn't think about skin secretions. after I put them in flips, I don't touch again, and I put silica gel packs in my coin box. and I check out my rather small collection frequently. am I doing enough?
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Pillar of the Community
3352 Posts |
*Trust me ... I just want to touch your sweet coin for a short moment* 
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Bedrock of the Community
United States
10045 Posts |
Thanks W00zi--perhaps I should be more careful with my coins.  I live near salt water, and I'm careful to keep my coins sealed from humidity and airborne salts. The strange thing about "bronze disease", you would think brass fittings on boats would be corroded in a similar way, but they're not. There are bronze statues right on the water here that don't corrode either. Perhaps BD also has to do with impurities in the original metal?  I don't recognize Doug's coin, but that's a sad progression! 
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Valued Member
United States
168 Posts |
Quote: would think brass fittings on boats would be corroded in a similar way great question. There are alloys of brass which are highly resistant to attack by chlorides. And as for the bronze statues, I will assume they are made of a corrosion resistant bronze alloy like aluminum and copper (there are many alloys of copper which are defined as bronze). https://en.wikipedia.org/wiki/Bronze
Edited by w00zi 06/25/2012 10:55 pm
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Moderator
 United States
23731 Posts |
Really sad to see that happen.
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Pillar of the Community
United States
3499 Posts |
Yikes, that's too bad. I guess that it just shows how fragile ancient coins can be.
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Pillar of the Community
United States
3229 Posts |
Doug. I am sorry to see your bronze disease blues  On a plus side: it looks like you have arrested the decay. Did you soak the coin in distilled water and then bake in the oven as a cure? Do you have a protocol that you use for BD? Do you plan to ren wax this coin after you are convinced the BD is gone? I know that there is more than one oppinion on how to deal with BD. Would like to hear your oppinion:)
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Valued Member
Egypt
139 Posts |
Wow :S that hurts just to watch. I hope that is the last coin that does that with you.
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Pillar of the Community
 United States
1549 Posts |
This coin was treated with an approximation of Sodium sesquicarbonate (home made solution from Sodium carbonate and Sodium bicarbonate) followed by a wash in distilled water and drying. The coin is still in the drying phase. It will be watched daily for a while and then weekly before it is put away again. I do not believe in waxing or any coating that will hold whatever is inside in there. This is only my second BD coin since I try to avoid buying them. I believe from the original photo that the coin had been waxed with colored wax in the areas that turned green. Notice there is no green in the left photo but there is surface irregularity there.
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Replies: 15 / Views: 1,690 |
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