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5kop1764EM nice overstrike - but corroded


sigistenz

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Hi friends, despite my vow to never buy a corroded coin again.....

I got recidivous.... :sorry:

could not resist this overstrike coin. But were there not the ugly corrosion.....

What would you do to soften the contrast a little?

Thank you, Sigi

 

QM1iL6.jpg

 

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This is not a bad coin - doesn't seem to be too heavily corroded! I believe you should always obtain a difficult coin despite it's condition if the price is right. You can always upgrade later and not worry about not finding a better example ten years down the road. (if not longer :) )

 

That said, I don't remember seeing any 5 kopek EM coins overstruck over 1762 10 kopek. Wow.

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I don't think it looks so bad. At least to me, to judge from the picture, the corrosion looks stable. Probably has been cleaned many years ago. But I think any attempt to improve it today would probably be dangerous. At most, maybe a little olive oil.

 

Nice overstrike, Sigi! :bthumbsup:

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Hi Sigi. I have coins with verdegris, that once restored as best as I could with much trial and error, and after years of aging to regain some modest patina, have this same look. The dark areas have much to do with the microscopic texture of the areas that were corroded. They will not color the same as the smooth fields and struck detail, smoothed somewhat from circulation. Still a very nice coin! Leave it be!

 

(ps can you find any Elizabeth 5K under there somewhere?)

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Hi Josh, my own tries most often also led to worsebettering :shock:

with very few exceptions. Leave it be, you say. But in a tray of 25 coins with 24 of them being nice, it sticks out. I am still thinking to do something about it.

As to any Elizabeth traces, I can't say. This is a very powerful overstrike. There are some indistinct traces of undercoin, but I cannot attribute them to Elizabeth - they are to weak and too fractional to determine wether they are Peter's or Elizabeth's. Of course, not all of the 10kop1762 were overstrikes - quite some were struck on new planchets.

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I don't think it looks so bad. At least to me, to judge from the picture, the corrosion looks stable. Probably has been cleaned many years ago. But I think any attempt to improve it today would probably be dangerous. At most, maybe a little olive oil.

 

Nice overstrike, Sigi! :bthumbsup:

 

Hi Bob, I once soaked a similar coin in olive oil for a year without seeing any change. Would you heat the olive oil or how would you proceed?

Thank you - Sigi

 

.

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This is not a bad coin - doesn't seem to be too heavily corroded! I believe you should always obtain a difficult coin despite it's condition if the price is right. You can always upgrade later and not worry about not finding a better example ten years down the road. (if not longer :) )

 

That said, I don't remember seeing any 5 kopek EM coins overstruck over 1762 10 kopek. Wow.

 

 

Hello Hisa, I just don't like an unpleasant coin in a tray of 25. It always catches my eye.

As to EM 5 kopeks struck over the 1762 10kopek, you can see a 1763 and another 1764 in my collection - link below.

Now I am unsure wether to replace my old 1764 with this new (corroded) one. It is much bolder.

Problems, problems........... :crazy:

Sigi

 

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Sigi, if you can get your hands on Verdicare, I highly recommend you to give it a try. This is one of the links: http://www.wizardcoinsupply.com/products/verdi-care.html

 

 

Not too sure how the shipping would work but do inquire.

 

You get results quicker than olive oil and I had mostly good results. The only exception is when the coin was cleaned and was covered by artificial patina and verdigris - there's not much you can do with either olive oil or Verdicare other than letting it retone.

 

Give it a test on a lower value 5 kopek before you take my word for it :)

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Sigi, if you can get your hands on Verdicare, I highly recommend you to give it a try. This is one of the links: http://www.wizardcoinsupply.com/products/verdi-care.html

 

 

Not too sure how the shipping would work but do inquire.

 

You get results quicker than olive oil and I had mostly good results. The only exception is when the coin was cleaned and was covered by artificial patina and verdigris - there's not much you can do with either olive oil or Verdicare other than letting it retone.

 

Give it a test on a lower value 5 kopek before you take my word for it :)

 

Hello Hisa, I ordered the stuff, thank you :drinks:

Will post result.

Sigi

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Hi Bob, I once soaked a similar coin in olive oil for a year without seeing any change. Would you heat the olive oil or how would you proceed?

Thank you - Sigi

 

.

 

Hi Sigi, I never tried heating the oil. But it is important to use extra-virgin quality because the cheaper oil has much higher acidity. Like gxseries said, try it on something common first.

 

I have had mixed results from olive oil in the past. If the corrosion is in a very limited area and not too deep, it can be very effective. But with this one, I expect to still see the variations in toning after soaking the coin. Maybe you can get rid of the little green specks, but the darker areas will probably not change much.

 

Here are before and after pictures from an experiment I did:

 

BEFORE...

 

Russia_2_Kopeiki_1824_EM_PG_obv.thumb.jpRussia_2_Kopeiki_1824_EM_PG_rev.thumb.jp

 

AFTER:

 

Russia_2k_1824_EM_PG_obv.thumb.jpgRussia_2k_1824_EM_PG_rev.thumb.jpg

 

Good luck ... let us know what the outcome is!

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Hi Sigi and all! Nice coin! I must agree with Josh, Sigi. Verdicare, is a good product, but gives good results mostly on small spots and on a surface that is smooth all over. I had experiments with Verdicare on a similar 5 kopecks coin (problems / age - wise) as yours and the only result was making it's original patina lighter after prolonged use, as there was little to no result on a dark area. That actually makes it looking worse, due to the contrast between the light and dark areas. Verdicare helped a little with removing the green, but did not help with big dark spots on 5k that were uncovered under the green. Unfortunately, I see only two choices here. Leave it be. Yes, it's a little ugly, but it is what it is. Or, try and change it's color all over. The only (and unpopular with me) method may or may not involve mechanical cleaning / chemical cleaning first, that makes the area smoother and more alike to touch. And as I am usually not happy with the result after that, as the coin then looks like a Christmas tree decoration, I would try to change the color to a dark brown with a somewhat easy, but complected method (due to practice and trial and error). After mech / chem cleaning coin that is pretty much has been striped from patina left in the distilled water for 48 hours, changing the water and turning the coin 2-3 times. After that (important!) dry it with fan heating it up a little, to remove any moisture. Once it is "decontaminated" and dried, use somewhat heat resistant gloves to hold it. Use bamboo sticks. Light one and holding coin parallel to the ground but above the level of your eyes, so you can see, bring the burning bamboo stick very close (almost touching) to the surface of the coin and move the fire around the coin surface area. It will look like coin becoming a little moist, due to un-burn oil form bamboo ending up on the coin surface. After the coin is all covered, cool it down a little, to it's not painful to touch, but not to the room temp, and before the oil sets rub the coin with your fingers, smoothing the coverage down. Examine the color (usually light brown). If not happy yet, repeat the procedure after cooling coin down completely and giving it a couple of hours for the color to set. If still not happy, put your fire / heat (bbq) gloves back on and heat the coin over open gas-fire. Here it is important not to over-heat the coin, so it doesn't loose it's "ring" and doesn't turn completely dark. Heat it briefly on both sides and let it cool for a few hours, remember as times goes by and coin cools down, the color may still darken further, so do not try to make it look a desired color when it is still hot or it will go even darker that you would like. If still not satisfied, repeat the heating. Take care with not letting the oil on the coin's surface catch fire. If that happens - remove it from the fire, blow the fire out and rub the oil all aver the coin again, until it hardens a bit. Once you are happy with the color result, leave it to dry for about a week. As much as I hate this drastic method for coin looses its original patina, sometimes it is a last resort. Experiment with some common coins first, it's fun. And think if you what to do this with your better coin... Whatever you decide, good luck, and please share the results.

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Good example, Ex!

Artists who work in metal sculpture have for hundreds of years developed techniques to artificially patinate metals. Bronze, copper, Brass, silver.... all can be made to look "old". The techniques and recipes us heat, flames, and a whole college chemistry class worth of various acids, salts, and other assorted ingredients. There is a LOT of trial and error, and patience. It is a skill/hobby unto itself. How much time do you want to spend ?

 

 

I work in Architecture. Verdigris on copper is a desirable look. I have seen some go to great lengths to make a brand new shiny copper roof on a historic building look old. The main ingredient of the old timers recipe? Yup. Horse piss. :shock:

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Hi Sigi, I never tried heating the oil. But it is important to use extra-virgin quality because the cheaper oil has much higher acidity. Like gxseries said, try it on something common first.

 

I have had mixed results from olive oil in the past. If the corrosion is in a very limited area and not too deep, it can be very effective. But with this one, I expect to still see the variations in toning after soaking the coin. Maybe you can get rid of the little green specks, but the darker areas will probably not change much.

 

Here are before and after pictures from an experiment I did:

 

BEFORE...

 

Russia_2_Kopeiki_1824_EM_PG_obv.thumb.jpRussia_2_Kopeiki_1824_EM_PG_rev.thumb.jp

 

AFTER:

 

Russia_2k_1824_EM_PG_obv.thumb.jpgRussia_2k_1824_EM_PG_rev.thumb.jpg

 

Good luck ... let us know what the outcome is!

 

Hello Bob, thank you very much for your time and mostly for showing an example before and after. Your coin sure looks better after soaking, less dark. But reading Eugene's experiences makes me somewhat hesitant. I'm afraid that on my coin the nice brown could also get lighter with the dark areas remaining dark - if not darker. The annoying contrast would then be even worse... :shock:

Still undecided what to do - but I'm not in a hurry.

Sigi

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Hi Sigi and all! Nice coin! I must agree with Josh, Sigi. Verdicare, is a good product, but gives good results mostly on small spots and on a surface that is smooth all over. I had experiments with Verdicare on a similar 5 kopecks coin (problems / age - wise) as yours and the only result was making it's original patina lighter after prolonged use, as there was little to no result on a dark area. That actually makes it looking worse, due to the contrast between the light and dark areas. Verdicare helped a little with removing the green, but did not help with big dark spots on 5k that were uncovered under the green. Unfortunately, I see only two choices here. Leave it be. Yes, it's a little ugly, but it is what it is. Or, try and change it's color all over. The only (and unpopular with me) method may or may not involve mechanical cleaning / chemical cleaning first, that makes the area smoother and more alike to touch. And as I am usually not happy with the result after that, as the coin then looks like a Christmas tree decoration, I would try to change the color to a dark brown with a somewhat easy, but complected method (due to practice and trial and error). After mech / chem cleaning coin that is pretty much has been striped from patina left in the distilled water for 48 hours, changing the water and turning the coin 2-3 times. After that (important!) dry it with fan heating it up a little, to remove any moisture. Once it is "decontaminated" and dried, use somewhat heat resistant gloves to hold it. Use bamboo sticks. Light one and holding coin parallel to the ground but above the level of your eyes, so you can see, bring the burning bamboo stick very close (almost touching) to the surface of the coin and move the fire around the coin surface area. It will look like coin becoming a little moist, due to un-burn oil form bamboo ending up on the coin surface. After the coin is all covered, cool it down a little, to it's not painful to touch, but not to the room temp, and before the oil sets rub the coin with your fingers, smoothing the coverage down. Examine the color (usually light brown). If not happy yet, repeat the procedure after cooling coin down completely and giving it a couple of hours for the color to set. If still not happy, put your fire / heat (bbq) gloves back on and heat the coin over open gas-fire. Here it is important not to over-heat the coin, so it doesn't loose it's "ring" and doesn't turn completely dark. Heat it briefly on both sides and let it cool for a few hours, remember as times goes by and coin cools down, the color may still darken further, so do not try to make it look a desired color when it is still hot or it will go even darker that you would like. If still not satisfied, repeat the heating. Take care with not letting the oil on the coin's surface catch fire. If that happens - remove it from the fire, blow the fire out and rub the oil all aver the coin again, until it hardens a bit. Once you are happy with the color result, leave it to dry for about a week. As much as I hate this drastic method for coin looses its original patina, sometimes it is a last resort. Experiment with some common coins first, it's fun. And think if you what to do this with your better coin... Whatever you decide, good luck, and please share the results.

 

Eugene, thank you so much for the detailed advice! You sacrified much of your precious time! I apreciate very much your warning that Verdi-Care could lead to worsening the contrast! I'll keep a print out of the bamboo method and will try it when I have a few quiet hours ahead. :yes:

Thank you again, Sigi

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  • 3 weeks later...

Hi Sigi, There may be hope in the air... I haven't tried myself yet, so hopefully someone who has may be able to share their experience, but I am told that this kind of black oxidisation may possibly be removed by Trilon B (also known as EDTA disodium) and available on eBay via chemicals suppliers.

 

You can read and do a bit of research on that product. I actually should have it in my garage somewhere, as I remember buying it a while ago and never experimented with it as after a while I forgot why I bought it, just remembered that it was for experimenting with coin cleaning. The other day I've been reading an article on "On the cleaning of ancient coins from numismatic collections (O. Vasilyeva)" in Russian it is given in full.

 

I started searching for an answer to a black copper oxidation problem, as they mention it, but do not talk about remedy, and I found a couple of articles that suggest that Trilon B may be an answer. There will be no patina left obviously enough, but when you have black oxidation, you don't usually have any patina left anyway, or it would protect coin from it.

 

What I am not sure about is, once removed, should it be possible to patinate the coin without bringing the black oxidation back. I guess it should be possible, but need to experiment first. No idea when I will be able to get around to it... But if anyone tried this method before, I am eager to know the results...

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Hi Eugene. Thank you again. I experimented with EDTA awhile ago. It first takes the patina away and then all the oxidation. It leaves a piggy pink surface all over. As EDTA takes all the impurities away, the surface appears rough and pourous but unfortunately not evenly: The formerly dark and oxidated areas show even rougher. As a result light is reflected differently there and those areas do always stick out from the rest of the coin. Even if you get the coin brown again - the rougher portions will always contrast annoyingly. :doh:

 

Maybe wax could be of help but I did not try that, the coins in question are no longer with me.

Sigi

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Thank you Sigi for letting me know. It sounds like a pretty radical cleaning resolution. I may leave it as a very last option. I really don't have a coin to experiment with at the moment, but if i'll do, I will share the results... Cheers!

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It is not radical, does not harm the metal but removes anything else. Including the small impurities included in the surface.

 

Sigi

 

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It is not radical, does not harm the metal but removes anything else. Including the small impurities included in the surface.

 

ammonia will do the same thing.

If a surface is worn smooth as during normal circulation, any porous areas fill flush with patina/ dirt/ oil / etc and are incorporated into the "skin" of a coins surface. anything that remove oxidation, will clean out these pores, and leave a rought texture that will never retone. verdigris eats copper, so when the verdigris is removed, obviously the eaten away copper surface is no longer smooth, relative the the rest of coin.

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I don't know if ammonia can remove the black copper oxidation, but the rest of patina and most salts, probably yes. I agree that once you uncover the black spot(s), the surface where it sits is already rough and patina-free. May as well clean the coin to the metal and deal with rough but clean spots later. As long as the surface of the coin is now of the same color it may be possible to smooth it out with the first method i described above, as oil will fill the empty space on the rough surface. Not ideal, but may be better than now, but a little risky. I would think twice, leave it as is, or modify its presentation.

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