Patina - what is it? Where to apply patination

From lovers of antiques, you can often hear such a word as "patina". What is it, certainly would like to know many Internet users. Below in the article, we will try to give the most detailed answer to this question. So, what is a patina?

Definition of concept

Everyone who ever visited the museum, probably saw the greenish old coins, darkened with time candelabra, sconces, etc. Covering these metal objects with a touch and called patina. The color of such a film can vary widely. Most often formed under the influence of atmospheric factors with natural aging patina has a greenish tinge. But sometimes it is brown, dark gray or bluish.

Chemical formula

The answer to the question: "Patina - what is this?" From the point of view of a chemist is very simple. The copper-formed film is nothing more than ordinary CuCO ₃ . This can be, for example, Cu ₂ (CO ₃ ) (OH) ₂ or Cu ₃ (CO ₃ ) 2 (OH). The raid of the first species has greenish shades (malachite), the second - bluish (azurite).

Natural patination usually occurs for quite a long time. Most often, a film of a substance such as copper carbonate on products, depending on the conditions, is formed within 5-25 years. If the object is in a humid environment, oxidation, of course, will go faster. In a dry room, the product will be covered later, respectively.

Initially, the concept of "patina" (what it is you now know) was applied only to a film formed on copper, bronze or brass. Later, the same word began to be called and the plaque appearing on a tree, a plaster cast, a bluish tinge on blued steel, etc.

Patination history

Everyone knows that ancient things look solid and prestigious. The reason for this is usually copper-patina carbonate. Since it is very long to wait on the surface of this or that product for a particular product, various methods have been developed that allow it to be obtained artificially.

The first hand-made things started to be made in the 14th century in Florence. For patination, a gypsum was used to fill the voids on the surface of the wooden products. After the alabaster mixture dries, gold foil is glued onto the product . Then everything was covered with varnish.

The technology of artificial patination of metals has also been developed quite a long time ago. Ancient masters noticed that the coating formed when the fat burns on metal dishes delays its rusting. Therefore, approximately the same in the chemical composition of the film began to be applied to sculptures and other artistic casts.

Where patination is used

Today, this technique is also more often decorated furniture intended for living quarters. Sometimes patination is used to artificially age the decor in the offices of business people. Very elegant look and finished in this way forged products. Patination can be decorated with metal railings of stairs, fences, balconies parapets, etc.

Also very often this technique is used for artificial aging of copper and brass coins. As in the past, patination can sometimes be seen on cast metal (steel, bronze and cast iron) decor items. It happens that in this way, souvenir "old" coins, medals, coats of arms, etc. are made. In many cases, artificial patina covers copper chandeliers, sconces, decorative plates for sockets, etc.

Artificial patina: aging paint

For the patination of furniture, panels, metal gratings , etc., this very gentle technique is often used. The aging of the paint is as follows:

• A product made of metal or wood is thoroughly cleaned and degreased.

• Its surface is ground, and sometimes lightly bleached.

• The actual patination is in progress. Paints are usually acrylic. Such compounds are resistant to adverse environmental influences and at the same time are inexpensive. For the design of small products, other, more expensive dyes can be used.

• Surface grinding is performed. In this case, the protruding details of the relief are highlighted, and the depressions remain dark. As a result, the patina coating is uneven in tone.

• The product is covered with a protective layer of varnish or oil (for wood).

Grading of forged, chased and cast products by chemical means

Patination with reagents is often used in the manufacture of metallic decorative products. In order to obtain a noble film on such things as embossing, sculpture, grating, etc., a wide variety of chemicals can be used. A natural green coating on copper, bronze and brass objects is very difficult. But you can get a patina of other interesting colors. For example, sometimes the processing of copper products is made by such a composition:

• Sulfuric liver - 2-3 g;

• Table salt - 2-3 g;

• Water - 1 liter.

When copper products come into contact with the resulting solution, a light patina of a pleasant gray shade appears on them.

For the artificial aging of brass decor items, the following composition is often used:

• Sulphonate sodium salt (fixer for film) - 60 g;

• Nitric acid - 5 g.

As a result of mixing these ingredients, a violent reaction begins. The color of the patina in this case is almost black. Such a solution the master tries to use as quickly as possible (maximum within 20 minutes). Otherwise, it loses its properties and becomes unsuitable for patination.

As you can see, for aging of metal objects of a decor by a chemical method often enough dangerous substances for human health are used. Therefore, they produce such patination only in gloves and with open window pane.

Where thermal patination is used

This technology is often used for the manufacture of beautiful steel products. For example, by a very simple technique, blacking is carried out. The metal is placed in a fire and held there until it turns red. Then it is very quickly dipped in a container with engine oil. As a result, a black patina is formed almost immediately on the steel surface.

Here such an image and an artificial "patina" is applied on metal and wooden surfaces. What is it that we have found out. By and large, the natural patina is a physical reflection of the decades since the manufacture of the product, centuries, and sometimes even millennia. Various kinds of artificial aging technologies are used, to a large extent, for the manufacture of all kinds of decorative products that can make the interior of a dwelling solid and prestigious.