How to re-patinate a cleaned ancient bronze coin?

Hi All,

At times an ancient bronze coin has to be cleaned or one that has been purchased has already been cleaned and has that terrible bright copper look.

Is there a good method to bring it back to something similar to the other coins in the collection.

all the best,
Col

 

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I would just leave it out and let it re-darken naturally. Yes, it will take a long time, but its better than a fake patina. I don't think you'll find too many fans of fake patinas over here.

This coin was probably stripped of most of it's patina many decades ago. I'd imagine it was mostly bright yellow back then, but now it's a darker light brown. Will it ever have a patina like you see in coins buried for 1,500+ years? Nope! But it might darken a little more over time...and I say better that than a fake desert patina or a painted patina. At least what you see here is an honest representation of the coin, and not some fake paint/glue job.

 

Please don´t, Col! There ARE people out there who DO like their bronzes unpatinated (like myself ), but I doubt anyone likes an artificial patina.

 

I'll be the contrarian here and say that some repatination jobs are nothing short of art. It's all chemistry. If there's no process by which you can tell fake from legit then you might as well let it go and not let it affect you one way or the other.

The crudest efforts are done by heating the coin with sulfur which results in a black coating. More sophisticated work is normally done by using multi-step processes involving cupric sulfate, lead acetate, sodium thiosulfate and others.

I've very little actual experience but I'm sure there are Google-able recipes.

Rasiel

 

There is no need to repatinate a bronze coin. It will slowly repatinate itself over time. It might be "art," but it's still fake, just like if you painted black hair on the obverse portrait. The only reason you might artificially repatinate a coin would be to make a quick sale. If you are planning to keep it in your collection, let nature do its job.

 

Bury it and have your great great grandkids dig it up.

 

I would not go for re-patination. As stated above there are folks who like coins that have no patination. Gives a better idea of what a coin actually looked like in the publics' hand at the time.

 

I want to clarify that I'm not recommending the OP try to do this. Just pointing out the obvious; that it's done and done frequently. Some will go so far as to call this "chemical tooling" but whole-coin treatments to me are another class of. By far I'd rather have the un-messed-with piece but figure there's no point in stressing out if/how/to what level it's had makeup applied.

Or just collect silver and gold I guess ;-)

Rasiel

 

Your decision- no one else’s.. you own the coin.
I have done this to 1 coin that I saved from bronze disease - and to do so I had to strip it clean. I then used Jax to re-patinate and it looks awesome.
Please note that I never plan to sell this coin- it just looks better in my collection.

I am not trying to fool anyone... in my opinion it comes down to intent.

Good luck!!

 

Show the coin. I would like to see it and judge for myself. Like you said it is your coin. Do with it as you please. However, your intention to never sell or defraud someone may be fine while you live. What happens when you heirs get ahold of your coins? Just sayin'.

 

On vacation but will show it over the weekend.. or Monday at the latest.

Please note the following before judging me:

- this is a coin in very low grade: an Agrippa/Neptune As .. but a very historic coin in my opinion.
-In this lower grade I do not think many would have put in the effort I have to save it.
-I have no intention in selling the coin
- I have noted what was done on the flip
-I can’t guarantee that the flip will stay with the coin.. but who can guarantee what happens after death?

-I am very happy to have the coin in my collection.. and appreciate it all the more after the stress and effort it has taken to preserve this coin.

I do not regret my decision (and in fact it can be reversed very quickly if anyone wanted)....

Highly Recommended under similar circumstances.. but to each his own. I can deal with the naysayers.
Just sayin’

Link to the product with examples:
https://nobleromancoins.com/product_info.php?products_id=48

 

My understanding, which could be wrong, is that repatination is standard practice when auction houses and dealers clean/conserve bronze coins. I'm not particularly bothered by the practice. I'm not talking about painted on or rubbed on opaque colorants and fillers, I'm talking about the many chemical patination recipes available for bronze art, artifacts, and coins.

 

When I started collecting, I bought many uncleaned lot. I did some test with electrolysis and sometimes went too far in the cleaning process. Then I tried to repatinate them with different chemical techniques. The best result I got was with Jax Green Patina solution. But it was with very worn coins. Not sure I’d do the same with nicest coins....

 

Claudius, I went to the site you highlighted and the coins seem more than reasonable, quite inexpensive, actually. I assume you have experience with them. What can you tell us more about it? Where will these coins come from? Reading between the lines it does not seem to be the USA. Any problems with getting these coins through US customs? Delivery time? Returns? I am used to dealing with US or Canadian dealers and know what to expect. What could we expect from this business? Thanks.

 

I have purchase the Jax solution from them as well as some "premium" uncleaned coins from them when I started out (I believe the coins originated from the Balkans region). I was happy with the results ... but I have moved on from uncleaned coins as I think you get better bang for your buck (and better coins) by buying cleaned coins individually.

The company seemed very reliable to me and provided good service. They are also based in California, USA... so no issue with shipping.

Hope this helps.

 

Thanks. My main concern was in dealing with a firm based in a part of the world that offers coins that may not be permissible to the recent interpretations of what may be legally imported from outside the US.

 

Deller's darkener will take away the shine but not coat it with a paint. It has the consistency of vaseline. I used it when I used to buy uncleaned lots. Not sure where you'd get it nowadays...

 

I don’t really have a problem with repatination so long as there isn’t a deceptive intent, like hiding a filler or trying to charge more for an attractive fake patina. It’s nowhere near on the same level as tooling, which actually alters the art.

JAX seems to be one of the more commonly used. I’ve only ever used it on small areas of a coin that were damaged by bronze disease. It produces a color similar to the dark brown coins seen above posted above.

 

Well I am back from vacation and as promised I will show my "re-patinated" Agrippa coin...
I must say that I am so thankful for this thread as I see now that the problem has reemerged.
I had the coin in quarantine for the last 6 months or so and sort of forgot about it as other projects have taken up my time.

Agrippa's frontal lobotomy is the damage from the original bronze disease. The coin was fully stripped of patina but you can see the applied Jax certainly did give the coin a more pleasing look (sorry for the poor photo - but you get the idea).

The coin is now soaking in distilled water and I start the process again... very hopeful of saving this piece of history.

Again I am stating that I never have the intention of selling the coin (would I even find a buyer?).. this is purely to preserve and enjoy a coin in my collection.

 

Well, I'm glad you caught the bronze disease. Change the water every two days or so. Do this for around 2-3 weeks.

Which actually brings up a question. If you followed this procedure, you'd probably end up using about a 1-2 quarts of distilled water. Would it be just as effective to plop the coin in a gallon of DW and leave it there for a month? We lazy people want to know.