How to apply patina on old copper coins: working methods. How to Apply Patina to Old Copper Coins: Working Methods Applying Patina to Silver Coins

Silver is a beautiful noble metal. Products made from it are simply mesmerizing - they shine, shimmer in the light and look like a real work of art. But as soon as you pick up silver or put on jewelry made from it, a rapid oxidation process begins. The metal becomes dull and loses a fair share of its attractiveness.

Therefore, many people prefer to darken silver. On the one hand, such products become like antiques, covered with a layer of patina. On the other hand, shiny silver with dark inclusions looks more attractive.

Blackening and oxidation

How to darken silver at home? There are two ways to do this: oxidation and traditional blackening. And the difference between these two methods is colossal.

During oxidation, silver is covered with a thin film of oxides, so the product receives a dark coating. But the coating is short-lived and easily erased. The difference is especially noticeable when cleaning - if you polish oxidized silver, it becomes covered with a network of lighter spots.

Blackening is the coating of a metal surface with a mixture of silver, copper and lead sulfides. This coating is resistant to abrasion and completely disappears only with prolonged boiling or exposure to acid.

Blackening on an industrial scale is carried out in various ways. But, as a rule, they all involve applying a powder from a mixture of silver, copper and lead sulfides to the product. The patina is fixed using the “dry” or “wet method” - in the first case, the product is fired after applying the powder, in the second, the metals are diluted with water to a creamy state, and the silver, after applying the mixture, is heated in a muffle furnace.

If we talk about how to darken silver in general, then experts identify the following methods:

galvanic - this technology requires special equipment, so it is not used at home;
mechanical - using graphite;
chemical is the most reliable method of blackening.

Mechanical method

How to darken silver at home with graphite? This is a fairly simple technology, and its result is due to the same processes that occur with lunar metal over time. That is, dust particles stick to it and firmly “eat” into the recesses. Using graphite you can simply speed up this process.

To blacken the product, they are lubricated with a mixture of graphite powder, iron oxide and turpentine, diluted to a pasty state. Then wait for it to dry completely and wipe the silver with a soft cloth. The older the product, and the more uneven its surface, the more noticeable the result will be. But in general, such blackening is less durable than that obtained by chemical or galvanic methods.

Blackening with an egg

How to darken silver at home with an egg? The technique is quite simple and you do not need to buy any additional funds. Everything you need is already in the refrigerator. So, to blacken with an egg you need to do the following:

Boil an egg or two if you have a lot of silver jewelry.
Separate the protein - it can be eaten, as it does not participate in the creation of a noble coating. All the substances needed for blackening are concentrated in the yolk.
The yolks must be placed in an airtight container and crushed.
Next, you need to place the silver in the same container, but so that the metal does not touch the yolks, otherwise the blackening process will take place too quickly and unevenly. Therefore, decorations must either be hung or laid out on a wire rack, or, as a last resort, insulated with a paper towel.
The products should be left with the yolks in a tightly sealed container for a day. If after 24 hours the result does not look very impressive, then you can leave the silver for another 1-2 days.
Remove the items and wash them with soap.
Polish all protrusions with a soft cloth.

Uses of iodine

How to blacken silver at home with iodine? When using this substance, the product must be cleaned first. Then apply an iodine solution with a cotton swab or cotton swab and put the silver to dry, best in direct sunlight.

When the metal darkens, you need to clean it with toothpaste - it will replace a mild abrasive. After cleaning, the bumps will shine, but the grooves will remain darkened. If the result is far from perfect, then the procedure must be repeated the required number of times.

The disadvantages of this technology are obvious: this blackening method is suitable for embossed products, but is not suitable for jewelry with a smooth surface.

Sulfuric ointment

You can quickly and effectively darken silver using sulfur ointment. This is a medicine that is mainly used to combat scabies pathogens in both humans and animals. Therefore, it is sold both in veterinary and regular pharmacies.

Sulfur ointment is thick, yellow in color and has a rather unpleasant odor. It must be applied to the product, and then heated to a fluid state using a hairdryer. After the ointment has transformed into a more liquid state, it can be more carefully distributed on the surface of the silver. When heated, you will see how the metal acquires a rich black-blue or purple color. Afterwards, the product can be wiped dry; if necessary, the procedure can be repeated.

Also at home, in order to darken silver, they use “sulfur liver” - a sintered mixture of sulfur and soda, which is thrown into water with silver. But it is not recommended to use this blackening technique at home, since the process will release hydrogen sulfide, a dangerous gas with an unpleasant odor.

How to clean blackened silver?

Applying dark plaque is much easier than removing it later. In order to get rid of blackening, you will have to make a lot of effort, and most likely you will turn to specialists for help.

But if you need to clean blackened silver while preserving the noble dark coating, then such a procedure will require special care. First of all, you need to give up brushes and use only soft cloths for polishing. This way the relief will remain darkened and the bumps will remain shiny. Toothpaste can be used as an abrasive. The blackened product cannot be boiled or cleaned with caustic substances.

And in cases where you take a patinated piece of jewelry to a workshop for cleaning, you need to warn the jeweler that you need to preserve the noble patina.

If the alloy from which coins are minted contains copper or any of its compounds, then sooner or later a film will appear on the surface of the metal - patina. It has a variety of colors and shades, and its appearance is due to the oxidation process of copper. It is also called noble rust, and all because the coin in such a shell is not subject to corrosion and has an attractive spring appearance. Patina is prized by collectors as it gives a collection a subtle antique feel.

If a coin needs cleaning but ends up losing its patina, don't worry. Artificial coins will come to the aid of numismatists patination which can be done even at home. Now there is no need to wait many months for the patina to appear naturally.

Patination of metal banknotes containing copper

Patination of copper-containing coins is possible in three ways.

The first option requires 20 grams of copper sulfate and 5 grams of manganese. They are dissolved in a liter of water and then heated to 90 degrees. It is necessary to carefully monitor the temperature, avoiding boiling, as otherwise the result is not guaranteed. Prepared coins are dipped into the hot solution, turning them over from time to time so that the patina is layered evenly. It is impossible to say exactly how long it will take you to fully patina, since there are many options for the desired color. Some people need a dark brown coin, while others need a reddish tint.
For the second option, you will have to go to the pharmacy to buy sulfur ointment. Generously coat the coin with this ointment and set aside for 3-5 minutes. With this method, patina forms very quickly, almost instantly. To prevent the metal from turning black, it is better to carry out the procedure near a water tap. As soon as you see the coin turning brown, rinse off the ointment thoroughly. Didn't make it on time? There's no need to get upset. Take Vaseline or vegetable oil, soak a soft cloth in it and polish the coin to the shade you require.
The third patination option is possible in the presence of sodium hyposulfite, which can be purchased as a fixative for developing photographs from film. Lightly heat the 10% solution and place a clean and pre-degreased coin in it for 10-20 seconds. The resulting brown tint will not only please the eye of a professional numismatist, but will also reliably protect the metal from corrosion. This method can also be used for patination of bronze items.

Patination of coins containing silver

Applying a new patina to silver-containing metal is fairly easy. To do this you will need ammonia or regular ammonia. Place the coin in the freezer for twenty minutes or half an hour. After the allotted time, carefully take the money by the edge with thin tweezers and bring it to the open bottle of ammonia. A miracle will literally happen before your eyes: the coin will turn grayish due to the emerging patina. Stop working on the specimen as soon as it reaches the desired shade.
An even simpler way is to use... a boiled chicken egg. After it is hard-boiled, the egg is cut and placed in a container with a fairly narrow neck. The coin is also sent there. Under the influence of hydrogen sulfide, silver changes color, becoming covered with a patina. This method is good because it achieves the most uniform coverage, without tweezer stains.

Patination of coins containing bronze

As mentioned above, to apply a new patina to metal containing bronze, a method based on sodium hyposulfite is used. In addition, ammonia and sulfur ointment are used with some haste. Numismatists advise experimenting with ordinary laundry soap, in which a coin is placed in the pulp for 2 weeks.

However, bronze coins are best covered with noble rust naturally, under the influence of sun, wind, and rain. In just one and a half to two years they will have an even and beautiful brown tint.

So, patina can be created artificially, and in some cases this is quite simple to do. However, I would like to warn novice collectors: in professional circles, any intervention in the appearance of a coin is always equated to a flaw and significantly affects the collectible value of the coin. It is advisable not to bring your collection to a state where it requires external patination.

Remember that a specialist can always easily assess by eye whether the patina that protects the metal is real or whether the shell was created artificially. Thus, the original “noble rust” envelops coins in a fairly thick layer, reliably covering chips and scratches. But the remake can be scratched by any sharp object.

Everyone knows that collecting is a rather meticulous activity. Absolutely every numismatist can spend weeks looking for the coin he needs in a suitable condition, but unfortunately, a small number of ancient coins are in satisfactory condition.

And therefore, you often have to buy coins that do not meet your expectations. Because of this problem, the numismatist community has found several techniques to give copper coins the desired appearance.

When and why is it necessary to patina copper coins?

There are several reasons why numismatists patina coins:

The coin was purchased or found in poor condition. For example, there are now quite a lot of copper pennies on the market that were dug up using a metal detector. In this case, pockets of corrosion will form on the “copper” and must be removed. There are cases where the find already has a beautiful patina, but this is rather the exception. This greatly depends on the soil and the place where it was found.
The second reason for the manipulation is the ignorance of the previous owners of the value of the preserved patina. Most often it is erased in attempts to add shine. Or it is thrown into acid, after which its color turns yellow-orange.
Increase in cost. There is no doubt that a copper coin with a brown patina will be more interesting to the buyer than an identical copy covered with green spots. At first glance, their safety is the same, but people are willing to overpay a little for the appearance.

Patination is the artificial aging of objects. It is carried out by a chemical reaction, during which a film or plaque is formed.

Today we will tell you in detail about the best methods and instructions for applying patina. Do not think that this is a simple task; in the process you need to maintain the proportions of substances, otherwise you may lose a rare coin forever.

Recipes for patination of copper coins at home

We will give you the best recipes for patination of coins yourself. If you want to achieve a decent result, then do not be lazy to prepare the material in advance.

A copper penny of the Russian Empire in need of cleaning

These words mean cleaning from oxides and various metal build-ups.

We advise you to first perform this procedure on inexpensive copies in order to practice a little. Don't be upset if something doesn't work out for you. It is difficult to achieve the desired result the first time. All comes with experience.

Sulfuric ointment

Patination with sulfur ointment is not the best option for collectors because it will easily rub off even with a sponge.

The color also cannot be called natural; it will have a gray tint.

The technology is quite simple and is carried out in three stages:

Apply sulfur ointment to a coin immersed in warm water,
Wait until it gets the color you want.
Wash off any remaining ointment with soapy water.

Warm water is necessary for the reaction to proceed slowly. This will help you choose the color tone more accurately.

Using sulfur ointment using the example of a 2009 copper cent

The only advantage of using sulfur ointment is the simplicity and speed of the appearance of patina.

Manganese and copper sulfate

If you want the coin to be covered with a strong, uniform patina, then the method using manganese and copper sulfate is best suited. It will give the most natural color to the product. The instructions for preparing the solution are not complicated.

A clear example of using a solution of manganese and vitriol

In total, you will need 3-4 grams of manganese, 10 grams of copper sulfate and half a liter of water heated to 90 degrees Celsius. During patination, do not forget to turn the coin over, otherwise the sides will be different in color.

Try to maintain proportions, otherwise you may not only not improve, but also lose your relief forever.

Also make sure to maintain the temperature, so don’t forget to heat the solution from time to time. There is no exact time frame for the coin’s stay in the solution; you just need to wait until the patina forms evenly.

Conclusion

After reading our article, you can give your copper coins a beautiful antique look on your own.

The main thing is not to be afraid to experiment and try each of the methods described above.

So you can compare the results yourself. Remember that the methods described are only suitable for copper coins; other alloys require different solutions.

Video: Patination or aging of copper coins

Patination of coins (artificial aging) is used to give the coin an appearance consistent with the age of the coin. Patination may be required after cleaning the coin, when the original patina is damaged or completely destroyed, as well as to give the coin a more aesthetic appearance.

Depending on the material of the coin, there are a fairly large number of methods for applying patina to the coin. Below are the most common ones.

Patination of copper coins with sulfur ointment

To demonstrate various methods of applying patina, modern coins will be used - 1 US cent. This coin is minted from copper, like many ancient coins. And most importantly, you can try different patination methods on several completely identical coins and compare the results.

Sulfur ointment is applied to the coin and literally within a few seconds it turns dark. After treatment with sulfur ointment, its residues must be washed off with soapy water. The patina resulting from the sulfur ointment has a fairly rich black color. The resulting patina is not quite durable and if you rub the coin with felt it will wear off, this should be used to give the coin a more prominent and contrasting appearance.

Patination of copper coins with ammonia vapor

In order to apply patina to a coin using ammonia, place the coin in a closed container with ammonia vapor for 10-30 minutes, but do not allow the coin to come into contact with the liquid. From a technical point of view, everything is simple, but when it comes to implementation, some difficulties may arise.

While preparing materials for this article, 2 coins were hopelessly lost. To prevent this from happening, follow these simple recommendations:

Since ammonia has a strong odor, patination should be done in a closed jar or container.
The coin must either be hung, secured by the edge, or placed on any object inside the container, but not just placed, but on a cotton pad, this will allow the coin to become covered with patina evenly on both sides.
You need to pour a little ammonia (5-10 grams) into the bottom of the container; it is best to do this at the very end after the rest of the preparations and immediately close the lid.
Under no circumstances should you heat a closed container; this will cause condensation to form on the coin and cause a very uneven patina.

Vapors from ammonia literally cover the coin in just a few minutes with an even layer of patina of a pleasant brown color. The coin stops shining and looks very attractive. If the coin is left for several hours, the patina does not become more saturated, but pockets of corrosion begin to appear.

Patination of copper coins with potassium permanganate and copper sulfate

Patination of coins in a solution of copper sulfate and potassium permanganate gives quick results and a pleasant brown patina. A coin or other object must be immersed in a boiling solution for 1-2 minutes.

To prepare the solution, it is best to use distilled water, for one glass of water (200 ml) you need to add 1 gram of potassium permanganate and 1 gram of copper sulfate, mix the solution thoroughly and place it on the stove in a container that you don’t mind - after patination of the coins, you most likely will not be able to wash the container .

The longer the coin is in the solution, the darker the patina can be obtained - after 10 minutes the patina becomes almost black. The 1855 penny from the example spent about 1 minute in a boiling solution. Also shown is an image of the coin before cleaning it with Trilon-B.

Patination of silver coins with sulfur ointment

Silver coins do not need as much patina as copper coins, but silver coins often sparkle white after cleaning and require a patina to achieve an older appearance.

To apply patina to a silver coin with sulfur ointment, almost the same operations are carried out as on a copper coin, but there are differences. First, the coin should be cleaned in ammonia or citric acid so that the surface is clean and there are no uneven areas. Next, sulfur ointment is applied to the coin, applied in an even, thick layer. Since silver is much less chemically active than copper, patina forms much more slowly. To speed up the application of patina, the coin must be heated; at home, the best way to do this is to place the coin on a cotton pad or soft cotton cloth and heat it with a hairdryer. In 1-2 minutes the silver coin becomes completely dark. Afterwards, the coin must be washed with soap to remove any remaining ointment.

After applying the patina, the coin was rubbed with felt so that the patina on the protruding parts of the coin was a little erased and the relief was more clearly visible. For this coin, such an operation gives a more advantageous appearance, but for heavily worn coins it allows you to raise the relief and sometimes distinguish details that were not noticeable before.

Patination of silver coins with egg

This is the simplest method of patination; no reagents are needed at all; in addition, the process is not fast and you can always settle on the desired degree of patina.

To patina with an egg, you will need to hard-boil one chicken egg, when the egg has cooled to a temperature slightly above room temperature, you need to peel it and put it in a container (ordinary plastic with a lid), then put a silver coin or several in the container and close the lid. It is better not to use a hot egg as it is not convenient to clean and steam comes from the hot egg and condensation may form on the coin which will lead to uneven patina. It is worth noting that it is advisable to first clean the coin with ammonia or citric acid so that the surface is completely clean and the patina lies evenly.

These 5 stamps were patinated with egg for five hours in a closed container, during which the coin was turned over several times. A coin patinated with egg produces a very specific patina, the so-called rainbow, it is very durable and shimmers in different colors depending on the viewing angle.

Patination of bronze/brass coins by electrolysis

In most cases, bronze or brass coins do not need additional patina, this is due to the fact that they are naturally quickly covered with a strong protective film of oxides and are perfectly preserved in this form.

But sometimes, during the cleaning process or when stored for a long time in the ground or in improper conditions, coins become covered with uneven spots with a patina of different colors. In other words, when a brass coin with good relief does not look beautiful, you can try to cover it with a patina using electrolysis.

These five kopecks are a dug coin; oxides of uneven color have formed on it in the ground over decades. Electrolysis was used to give it an even patina. A soda solution was used as an electrolyte, the current source was a charger for a car battery (current 2 A), a coin was attached to “-”, a sacrificial coin was attached to “+” (about the same nickel, it is important that the metal was the same , the same as the coin being processed). Patina application time is 2 minutes. After electrolysis, the coin was ground in soda paste.

Probably every more or less experienced numismatist collector has been involved in the procedure of patination of metal banknotes. This process means treating the coin so that its appearance matches well-preserved antique examples. It is better, of course, not to bring a collectible item to the point of having to apply an artificial coating of various shades that imitate centuries-old existence.

However, sometimes metal coins need to be cleaned of stains of corrosion and dirt - after all, they could have lain in the ground for many years. This is where the danger arises of not only not increasing the marketable value of the coin, but, on the contrary, completely destroying it, since along with the dirt, the noble layer of oxides (patina) formed as a result of natural aging is also removed.

It is better for beginners not to get involved with cleaning coins even if they really want to. Well, or if you try, then on “killed” coins that you don’t mind. All kinds of copper “poop” are quite suitable for initial experiments. Collectors with experience can take up this business, but following a certain technology for different metals. It is the metal of which the coin is made that dictates the rules for its cleaning and patination.

Gold money does not need to be cleaned at all. In special cases, if they are thoroughly dirty, they can be washed with warm soapy water, and then dried thoroughly between pieces of soft cloth, which will not leave microscopic scratches on the sanded surface.

Heavily oxidized silver coins can be cleaned using ammonia or a baking soda solution.

Slow reagents (for example, Trilon B) are best suited for cleaning copper or bronze coins. It is not recommended to use strong reagents such as sulfuric or nitric acid, since they, together with rust, can destroy small details of the design.

In general, one of the best ways to clean copper coins is considered to be ordinary laundry soap - plan it, dilute it in warm water to the consistency of sour cream and put the coin there. Let it soak and over time you will see that the soap turns green - unnecessary oxides and dirt come off. Often, after a coin has been in soap for a couple of months, it is ready and can be put into a collection.

If you nevertheless cleaned the coin in such a way that all its collectible advantages were washed away, then you cannot do without artificial patination (aging). From a scientific point of view, the noble patina on ancient coins is a surface oxidation of the metal. Gold products are practically not subject to such a process due to the extreme inertness of this chemical element - therefore they can not be taken into account. There are many ways to restore the patina on silver, copper or bronze coins. Let's list some of them.

Silver

To artificially patina silver coins, you only need a freezer and a bottle of ammonia. The money is placed in the freezer and after being there for half an hour, it is carefully removed using tweezers. Now all that remains is to hold it for a few minutes on both sides over an open container with ammonia.

Under the influence of alcohol vapor, the metal surface begins to oxidize and acquire a grayish tint (patina). All that remains is to achieve a uniform color on both sides - and we can consider it done.

Copper

A very natural patina is obtained as a result of the use of elements such as manganese and copper sulfate. The process consists of using a solution prepared from 0.5 liters of warm water (90º C), 3-4 g of manganese and 10 g of copper sulfate. Place coins in the solution and wait until a bright brown color appears on their surface. Moreover, as the water cools, it is necessary to warm it up a little, and turn the money over every 5 minutes. The result is a beautiful patina that is wash-resistant.

We tried this method a couple of times - we rubbed the coin with sulfur ointment, the patina also appears, but we can’t say that it is very similar to the natural one, the color is more grayish. But overall the coins look good.