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Copper Coin Conservation The Correct Way

 
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Author Previous TopicReplies: 14 / Views: 456Next Topic  
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 Posted 07/21/2021  9:19 pm Show Profile   Check westcoin's eBay Listings Bookmark this topic Add westcoin to your friends list Get a Link to this Message
Previous EAC President Bill Eckberg and all around good guy describes (quite eloquently) how and why to conserve and condition your copper coins.

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"Blue Ribbon" the coin conditioner Bill uses in the video is now gone forever, in it's place is another product Bill recommends in it's place called "Classic Coin Conditioner" found at some of the larger coin collecting supplies like Wizard, Brooklyn, etc.

Bill is also one of the authors of the EAC Grading Guide. An excellent reference if you want to learn more about grading using the often misunderstood Early American Copper "EAC" methods.




"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013!
ANA Life Member #3288 in good standing since 1982, EAC Member #6202, NBS Member, 2¢ variety collector.

See my want page: http://goccf.com/t/140440
Edited by westcoin
07/21/2021 9:22 pm
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 Posted 07/21/2021  10:28 pm  Show Profile   Bookmark this reply Add CentSation to your friends list Get a Link to this Reply
Thanks for the video link.

I have the Classic Coin Conditioner that I use on my LCs - states right on the label that it is a direct replacement for Blue Ribbon. I apply it with a cotton ear swab and no matter how little I think I have applied, it still seems like too much. It seems to dry to a glossy/satiny sheen [not sure if I like that].

I guess the objective is to 'seal' the surface of the coin to deter the effects of oxidation.
Those who know what's best for us, must save us from ourselves.
Edited by CentSation
07/21/2021 10:29 pm
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 Posted 07/22/2021  01:33 am  Show Profile   Bookmark this reply Add sel_69l to your friends list Get a Link to this Reply
"Don't clean coins!"
Here is a guy who knows what he is doing.

As correctly pointed out, polyethylene as used in a small clip lock bag is completely inert to coins. Only problem is that is translucent and almost impossible to see the fine detail of a coin inside the bag. Polyethylene is commonly used in food packaging, so it has to be OK for long term coin storage. It does have major problems as an environmental pollutant, because it doesn't break down.

Two reasons why those old valuable copper coins in really nice condition have not been affected by brushing:
1. The bristles in the jewelry brush are very soft, and
2. The copper coin with the protective patina that it has already acquired, is harder than the bristles of the brush.
To preserve a coin, the objective is to prevent air or liquid or solid contaminants from coming into contact with the surface of the coin.

In this case, that is attempted to be achieved by coating the coin in a mixture of mineral oil, diluted with trichloroethylene. (TCE) The chlorine in the TCE is strongly fixed as with dry table salt, to the render TCE inert. TCE is carcinogenic to the liver in large doses, so be careful when using this strong solvent.

(I have seen TCE used in the cleaning of F404 jet engine cores used in the F-18E Super Hornet, so it has to be safe, or you would have a $50 million hole in the ground and a dead pilot, if TCE wasn't safe for this purpose.)
I have more of a problem with the mineral oil. I would like to know more about the chemical constituents. Perhaps pure alkane parrafin wax diluted with TCE or acetone would be better. Pure metallic sodium is stored airtight under liquid parrafin oil.

Another alternative to protect a patinated copper coin's surface from corrosion is to spray it with clear coat acrylic lacquer. Acrylic is the same stuff used in air tight coin capsules.
Don't use clear coat on red unpatinated copper or silver coins, because the clear coat may flake off in patches with new coins, that could eventually lead to blotchy toning.

I think that it would be quite OK to rub Renwax** or similar on old copper coins to exclude air and contaminants from their surface, BUT you must first wash your hands thoroughly in soap 'n water, then properly clean your fingers with acetone, before proceeding. Suitably clean skin is sensitive to the coin's surface, and softer than the bristles of a brush.

** Renwax is used in selected situations by the British Museum in the cleaning and preservation of old copper coins - especially ancient coins.

With all of the abovementioned chemicals, refer to their relevant Safety Data Sheets, including acetone.
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 Posted 07/22/2021  12:11 pm  Show Profile   Check westcoin's eBay Listings Bookmark this reply Add westcoin to your friends list Get a Link to this Reply
All very good points sel_69l,

Bill didn't really touch on the patina much, but that is the truth. Good catch and addition to the talk.

I did not know all that about the polyethylene substance. I have used the little poly bags on primarily proof coins to protect against hairlines on loose coins in the past. Works well for me, and allows me to keep them in a soft PVC clear flip which won't scratch coins like the harder Safe-T-Flips archival holders can.

There was an interesting discussion not long ago on the secret Facebook group of the EAC members about copper coin conservation, One of the members stated he had Blue Ribbon chemically analyzed with a laser spectroscopy based test system to learn more about it and it's ingredients. The guy doing the work was a long time scientific engineer, he found no trace of Mineral Oil in it, so the debate is still out on the ingredients, unfortunately he caught Covid-19 and passed away in the middle of the work, the project died along with him, and it was never finished. The plan was to try and remake Blue Ribbon Conditioner using only safe and legal ingredients today. Though I hear that "Classic Coin Conditioner" is essentially just that, it is also what Bill Eckberg said he is now using, so good enough for me too. I also have a good stash of Verdi-Care which I will use on coins with more damage and corrosion or verdigris as a starting point, after a good soak in acetone.

I've researched a little into some of the more often used chemical compounds at museums. Stuff like Agateen,
Paraloid B-72, and Paraloid B-48N (these are generally only found in use with bronze and silver coins), The American Institute for Conservation of Historic & Artistic Works put out a few papers on their testing of these materials. However this is way above the average collectors head for the most part. If interested I have copies of the testing paper and results, shoot me an email if you would like a copy of the PDF. It's in depth and very scientific but not over one's head in depth.
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013!
ANA Life Member #3288 in good standing since 1982, EAC Member #6202, NBS Member, 2¢ variety collector.

See my want page: http://goccf.com/t/140440
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 Posted 07/22/2021  1:37 pm  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
This was quite helpful. Thank you, westcoin. I would like to see the pdf you have. I will pm you.


Quote:
The chlorine in the TCE is strongly fixed as with dry table salt


Sel, I think I know what you mean, but they aren't quite the same, and the distinction is critically important.

The chlorine and the hydrogen and carbon atoms in TCE are held together by bonds with mostly covalent character. Trichloroethylene exists as molecules, and its molecular weight is not large. That means it can evaporate, and with a boiling point about 21 degrees Celsius above that of water, it will be a little slow. The bond in this case is not so easily broken, so you are not so likely to wind up with free chlorine or chloride that could react with your coin while it is in contact with the coin. .

Sodium chloride—table salt—is held together by ionic bonds in a crystal, not existing as discrete molecules. Residual chloride salts don't evaporate to a significant degree under less than extreme conditions. As soon as water gets to it (and water vapor in the air will for those of us in damp climates), the compound readily dissociates into chloride and sodium ions. Chloride ion is the starring ingredient in "bronze disease," and that chloride can come from salt on your potato chips, from you, from dirt, and so on. Someone mentioned a vinegar and salt bath the other day. When I came to, I realized they were messing around with nearly worthless coins, so I didn't relapse back into unconsciousness. Sources of chloride are frightening if you hate corrosion.

We exude chloride salts. Because it is combined with oils in our skin, I almost always use water (to dissolve salts) and acetone (to dissolve oils) baths to reduce risks of finger prints showing up on the coins I buy. Some people are rather careless in how they handle bright shiny copper, and once corrosion sets in, it can at best be hidden. The oxidation is permanent. I think that is part of conservation—heading off the damage before it starts. If some of the other members here have a better process, please let me know. I think my process is similar to what some on here refer to as Bad Thad's polarity ladder" with omission of a really nonpolar solvent.


Quote:
I would like to know more about the chemical constituents.


Mineral oil is simply a mixture of some alkane distillates of petroleum. Alkanes are largely inert to reactions unless you burn them or go to extreme conditions in a reactor. Mineral oil has even been used as a laxative, and one can buy food grade mineral oil.

Other alkanes include the paraffin oil (depends on where you live as to what this name means, though) and polyethylene plastic that has already been mentioned. The "ethylene" refers to the original monomer. Once polymerized, it exists as massively long alkane chains.

And while I am doing this massive information dump, natural vegetable oils are not the same thing as these petroleum based oil and wax products. Vegetable oils have reactable functional groups on the molecules, so they can degrade over time. I think the degradation problem would be worst for less refined, unsaturated oils such as EVO. Good for the environment, but does not seem so good to me if you desire long term protection or lubrication of metal.


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 Posted 07/22/2021  2:07 pm  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
I am not sure why TCE was used with mineral oil—if those indeed were the two ingredients—unless it was to thin the mineral oil.

Just curious as to what the process is actually doing. What I see is:

1. The brush can remove loose surface contamination.

2. The brush works the fluid into the nooks and crannies.

3. The fluid leaves behind a layer of water repelling oil. Water is another star of most corrosion reactions, such as bronze disease. While oxidation of metals does occur without water, many metals form a passivating oxide layer in a dry environment, so no harm is done as the oxidation/corrosion process slows to a crawl.

4. A thin film of oil smooths the surface. The result is that light isn't scattered as much, so the surface looks darker and shinier. The effect is similar to waxing a car.

Anything else that I am missing?

Maybe some of these products have active corrosion inhibitors?

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 Posted 07/22/2021  5:00 pm  Show Profile   Check westcoin's eBay Listings Bookmark this reply Add westcoin to your friends list Get a Link to this Reply

Quote:
Maybe some of these products have active corrosion inhibitors?


Word was the stuff in Blue Ribbon was very similar to Brake disc cleaner, so you may not be to far off there.
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013!
ANA Life Member #3288 in good standing since 1982, EAC Member #6202, NBS Member, 2¢ variety collector.

See my want page: http://goccf.com/t/140440
Bedrock of the Community
Australia
18724 Posts
 Posted 07/22/2021  11:02 pm  Show Profile   Bookmark this reply Add sel_69l to your friends list Get a Link to this Reply
When chloride ions get into an aqueous solution, they provide an ideal vector for the promotion of corrosion.

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 Posted 07/23/2021  01:22 am  Show Profile   Check westcoin's eBay Listings Bookmark this reply Add westcoin to your friends list Get a Link to this Reply
Now I'm about to carefully tread into a subject area I know just enough to be dangerous in - chemistry.

There are two major types of brake cleaners: chlorinated and non-chlorinated. The first thing to know about chlorinated brake cleaners is that they are not legal in every state in the U.S. So this in inline with why Blue Ribbon may have gone away,


This was the quote from the person working on the Blue Ribbon replacement solution:


Quote:
The chemical analysis was done properly by one of the best in the business. He used to do this work for the air force and I have no reason to doubt his findings. I supplied the sample to him directly from my original Blue Ribbon bottle that I bought back in the early 2000s. There were about 9 different chemicals in there. 1,1,1 tri was one of them. Plus he told me there were a number of other industrial de-greasing agents and some sort of dye in there as well. I don't remember all of the details at this point. I was working with someone and we were trying to recreate the original formula's results without all of the harmful ingredients. Unfortunately the gentleman I was working with died from covid back in February. He was financing the project and it was his chemical engineering contact we were working with. After my friend's death, there is no way I can continue the project.


Then another comment from another person:


Quote:
Somebody who seemed knowledgeable on this subject told me via my YouTube Channel, that one of the chemicals in Blue Ribbon was "Trichlorethylene" nearly the same but not the same as "Trichloriethane" and it was essentially an automotive cleaner for brakes that evaporated very quickly. He said it was believed to be cancer causing as well.


So I misread the comment last night as it's a different chemical than a brake cleaner or de-greaser, but it's similar.

Numiscrat is the expert chemist along with BadThad on the CCF forums. But I do know that the stuff in Blue Ribbon was one of the tri chlors but I don't know the differences in
ethylene and ethane and if it even would make a difference in this case? Not that it really matters as Classic Coin Conditioner is the safe alternative and seems to work pretty well from my understanding, I haven't tried it yet, did order a bottle so we will see how close it is to the Blue Ribbon I remember. I do use and like Verdi-Care and it's an organic safe for the environment "green" if you will solution, that is supposed to also leave a protective film coating on the surface of the metal after application.

The solutions on the market are vastly different:

Classic Coin Conditioner, says safe, "green" and evaporates. Sounds similar to the Verdi-Care.

Coin Care or SDS-55060, is flammable, dangerous to exposed skin and sounds like it contains acetone, xylene or similar.

Conserv2 or SDS-55065, is similar to Coin Care, they say it's from the dental world and used to remove PVC trace off enamel, also it's safe for metals?

I'm sending the Data sheets to Numiscrat I'm wondering if he can shed light on what they may contain from the information revealed in the Data Sheets alone possibly?
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013!
ANA Life Member #3288 in good standing since 1982, EAC Member #6202, NBS Member, 2¢ variety collector.

See my want page: http://goccf.com/t/140440
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 Posted 07/25/2021  07:54 am  Show Profile   Bookmark this reply Add just carl to your friends list Get a Link to this Reply
I simply put all my coins in Albums and then the Albums in a zip lock bag. No chemicals needed.
just carl
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 Posted 07/25/2021  09:28 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply

Quote:
I simply put all my coins in Albums and then the Albums in a zip lock bag. No chemicals needed.


Zip lock bags? So, you are choosing LDPE, low density polyethylene, to protect your coins? That is simply a high molecular weight long chain alkane which is in the form of a solid rather than a liquid. Films made from PVC are hazardous to coins. You are choosing your chemicals well, just carl!

Everything is made of chemicals. All of them have their own characteristics, and some of those everyday chemicals, such as water and sodium chloride (table salt), are terrible for coins. When we choose materials and environments in which to store our coins, we are choosing which chemicals they will interact with during that time. Doing nothing is still picking and choosing the chemical environment around the coin.

Example: Last year, I bought a 1996 ASE proof in an auction a little cheaper that it should have been. It had thumb print in the field that for various reasons, I surmised was fresh. I won the bid, carefully treated it with water and acetone, and thus probably prevented lasting damage to the coin. My local dealer saw it after I worked on it and commented that he couldn't see anything wrong with it.

Doing nothing would have probably resulted in an etched in finger print and a bullion grade coin. Instead, I chose to use two chemicals, water and acetone, to remove numismatically hazardous chemicals, sodium chloride and bodily fluids (oils), from the coin.


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 Posted 07/25/2021  10:10 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
I am still reviewing the documents provided by westcoin. This subject is not trivial, and for newer members, perhaps stress should be placed on the words "conservation" as used by westcoin and "preservation" used on the video. These words should not be confused with amateur "restoration" which is what some people might try to do in "making their coin look better." While there is some overlap, restoration is often times more controversial. If you want an example of this in architecture, see the Wikipedia article on Viollet-le-Duc and the controversies surrounding the restoration efforts he led on ancient structures.

I am not a professional conservationist, but I think one might classify acetone and distilled water dips as conservation, whereas trying to make a circulated coin look uncirculated by polishing is ham handed restoration. Restoration has the capacity for destruction to some degree if not done by an expert. Even then, that brings up the subject of unscrupulous coin doctoring—repairing or modifying a coin which will never be 100% original, but doing it with the intent to deceive someone else into thinking it is.

The subject of "coin dips" probably exists to some extent in a gray area, hence the passionate feelings for and against and those who dip while feeling like they just sinned...

With all that said, folks dealing with ancient coins covered in crud (corrosion, dirt, ...) are in a different situation from those of us handling modern coins. I don't know near enough to go there at this time.

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 Posted 07/25/2021  10:57 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply

Quote:
So I misread the comment last night as it's a different chemical than a brake cleaner or de-greaser, but it's similar.


Westcoin,

Using a group of letters to designate a chemical can confuse anyone. I assumed I knew what they meant, and I assumed incorrectly. You may have been correct all along. I found this brake cleaner in a store yesterday:





Notice the numbers after the names? Those are CAS numbers and are used like Social Security Numbers or Driver's License Numbers. Chemists have to use those because common names don't always mean the same thing to everyone. "TCE" could stand for trichloroethylene, tetrachloroethylene, trichloroethane, and tetrachloroethane to name a few. CAS numbers are not so ambiguous.
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 Posted 07/25/2021  6:49 pm  Show Profile   Bookmark this reply Add sel_69l to your friends list Get a Link to this Reply
I take your point.
I only invented "TCE" for the discreet purpose of shortening my post a bit. I sometimes call trichloroethylene 'trike' for short, but I thought that may be less well recognized.
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