Coin experiment gives surprising results!

Reverse electroplating a 1982-D copper LMC. I found this experiment on Pinterest, if anyone wants to go find it for themselves.

It involves finding an old device wall transformer and crimping alligator clips to the ends. You immerse an old stainless steel spoon in a solution of CITRIC acid diluted with water and connect the positive clip to the spoon. I used 8 oz. tap water with the juice of 1/2 lemon as my solution. The negative clip attaches to the coin under test.

Once immersed, you need to ensure the spoon and coin remain apart, then plug in the transformer into your wall outlet. My transformer output was 16 volts direct current (vdc) and was strong enough. 12 vdc is good too, weaker and you must run the test longer. There are pitfalls, but worth it if you are careful as you will see by my results.

My original coin, lots of corrosion. The experiment is supposed to remove all non-metallic debris.

The coin will begin to fizz within a few seconds of plugging in the transformer, but the wires don't get hot or even warm. You must be careful attaching the clip to the coin to avoid adding contact marks. Here is after 30 minutes:

Next, after a total of one hour:

Next, 3 hours. Notice the halo effect where the clip was attached:

Final result after a light swab with acetone:

Honest...same coin. Acetone removed debris from the test including the halo. The only negatives were an additional new contact mark from the clip and the fact that it is now a cleaned coin. This coin was a sacrificial lamb to test the procedure, obviously it was not a "keeper". I will keep it as a specimen.
Comments?

 

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By removing the outermost copper atoms you also remove the corrosion that is chemically attached to them.

 

While in progress I had my reservations of effectiveness. I was amazed at the result.

 

I like the results.

Can you make something that makes contact with the coin and still conduct electricity, but doesn't leave marks?

 

The focus of the Pinterest article was to salvage coins found while metal detecting. Said it was used on some extremely damaged, buried coins, so, in this instance a useful tool to recover an otherwise unwanted, irredeemable coin that had been in the ground for decades, if not centuries.

 

You might put a flattenned piece of metal on either side of the coin to avoid the bite of the clip. But it would have to be copper as well to avoid dissimilar metals. Or you would have to find a specialized copper clip of some kind.

 

Just hit me...what if this coin had been a small date copper.....

 

....and I take your advice seriously. I will proceed with caution...I have plenty of "test subjects".

 

Old phone chargers are best for this, I also add a little salt solution.
I`ve actually had mine for around ten years, lots of examples on YouTube.

 

Most transformers/chargers will show the output. The voltage is not as important as the amperage. Phone chargers work well because of the low amperage. Higher amperage ones can cook a coin.

 

It's like elfen magic.

 

The limiting factor would probably be the resistance of the solution, and that's determined by its concentration (how much citric acid you put in) and the size and composition of the electrodes (coin and whatever you use on the other side).

If a charger says "5 volts, 2 amps", that means it'll provide 5 volts at up to 2 amps. Most likely, you'll draw nowhere near 2 amps, though, unless you touch the electrodes together (short-circuit). If you try to draw more than 2 amps, either the output voltage will drop, the charger will cut itself off, or it'll overheat and fail.

A higher-voltage charger will push more current through the same resistance. In other words, if a 5-volt charger pushes 0.5 amp through your setup, a 12-volt charger would push 1.2 amp (as long as everything is arranged exactly the same).

I really, really should experiment with this myself -- I've got a couple of power supplies that let me set the current, and then provide whatever voltage is needed to drive exactly that much current.

 

This form of silver electrodeposition or your explanation of electrolysis is explained in my new book "Forgotten Coins." There amay be hundred's? of Mexican Cap and Rays Eight Reales which are counterfeited as the direct result of silver electrodeposition or silver electrolysis. This advanced form of counterfeiting replaces the Sheffield Plate types that we discussed in Gurney's Eight Reale counterfeit book. We are currently looking deeper into these C&R 8R's in this post-1840 counterfeiting method. See this link - an entire chapter discusses this new form of counterfeit in raw and found in slabs:

https://www.amazon.com/Forgotten-Co.../ref=tmm_kin_swatch_0?_encoding=UTF8&qid=&sr=

 

Water softener (sodium sesquicarbonate) is safer for your coins than citric acid. You can even spare a patina if you are careful. This was the method used to clean the Bath Hoard:



Use about 2-3 teaspoons in 8 ounces of warm, distilled water. It takes a few to several minutes to remove the corrosion. Watch the coin closely.

Wash the coin with soap and water when you're done, then rinse in distilled water and let it dry naturally.

 

None the less.....


Looks cleaned to me.

 

Seasoned coin folk agree that my final result does indeed look like it's been cleaned, because it has been. However on a scale of 0 to 10, the original condition was a 0, and the salvaged result maybe a 2.
On a consistant basis, at least since 1962, I stay away from coins that need to be cleaned and am discouraged when I find one. And sometimes it happens the hard way.

I inherited a beautiful Peace dollar from my Mom back on 2007. It had a proof-like finish and I thought it was MS65. It came back from ANACS "AU58 Details"...they determined it had been polished, another form of cleaning or altering coins.

I remain a staunch supporter of non-altered coins, but sometimes you run across one you just gotta get the grime off of.