Author Topic: Akbar, Delhi dam,dotted divider varity, 981 AH  (Read 332 times)

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Offline Saikat

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Akbar, Delhi dam,dotted divider varity, 981 AH
« on: May 10, 2018, 05:46:59 PM »
Hi,
Below is a Akbar dam from Delhi. It is the scarce variety with dotted divider.
Weight: 20.66 gm
Date: 981 AH (Both sides have the date in number)
The coin may look bad with almost no patina left (photo #1). But this was after a few weeks struggle. When the coin was offered in auction, it was in a bad shape with possible bronze disease (photo #2). The reverse was absolutely not visible and there was almost no interest in bidding for this one. After I got the coin, it was boiled and bathed with soda mix immediately. That took out most of the greens stuff and made the reverse readable. Then it was another week in olive oil which made it much cleaner but also took out the patina along-with the hard crust between the letters.
Nevertheless, I am happy with the result achieved so far as the coin is now readable. However, I will need to restore the patina but that.
Thanks,
Saikat
« Last Edit: May 11, 2018, 07:38:29 AM by Saikat »

Offline Coinsforever

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Re: Akbar, Delhi dam,dotted divider varity, 981 AH
« Reply #1 on: May 11, 2018, 05:31:06 PM »
Very impressive results after cleaning it gently.
Coub is definitely a rare type of captioned mint.

Cheers ;D
Every experience, good or bad, is a priceless collector's item.



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Online Figleaf

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Re: Akbar, Delhi dam,dotted divider varity, 981 AH
« Reply #2 on: May 12, 2018, 12:08:39 AM »
Congratulations, Saikat. You resurrected a piece of history. You went about as far as you could go with the cleaning process, though you might want to try rubbing the remaining green spots with the double soda solution.

I am surprised the olive oil ate away the patina. Have you read the label and checked for acidic additives? The red glow on the coins makes me suspect that there was acid in play somewhere. Another possibility is that the olive oil contained natural acid. In general, Greek oil has the lowest acidity, rising as you go westwards and Portuguese oil has the highest acidity. Also, virgin press (salad oil) has a low acidity, while third press (cooking oil) is highest in acid. If the label is uninformative, in general, the cheaper the oil, the higher its acidity. Did you neutralise after the oil? Lukewarm water with liquid soap will neutralise acids.

Capnbirdseye uses caustic soda (drain cleaner) on coppers like yours. Haven't tried this yet, but it sounds great.

The patina will return in (lots of) time. Bad air will expedite the process. Coal fumes, containing lots of sulphur, work very well.

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline Saikat

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Re: Akbar, Delhi dam,dotted divider varity, 981 AH
« Reply #3 on: May 12, 2018, 09:57:35 AM »
All,
Thanks. It was a really a great learning process, only this time the subject was a rare coin so I have to be very cautious! I think I can try out with caustic soda. I have good result with silver coins earlier. I will wait for a couple of months to see how the residual green behaves, and then proceed with further cleaning.
The weight of the coin is rather high and possibly that indicates the coin is not damaged. The sandy crust is still obscuring the surface. I will have to find a way to remove the crust.
Thanks,
Saikat