Brass and bronze painting. Brown color (mordant) for copper, brass and bronze items Application of coloring compounds

Using simple chemical treatment, a multi-colored protective and decorative coating is obtained on the surface of the product. A small product is immersed entirely in a container with a chemical solution, a large product is treated with a brush, sponge, or foam rubber. In order for the resulting film to stick to the product more firmly and not become covered with plaque, after washing and drying it is wiped with a rag soaked in machine oil or in drying oil.

In order not to experiment every time in anticipation, in search of obtaining the required color tone on this or that material, stock up on samples of plates of steel, copper, brass, aluminum, treated with one or another solution, indicating their recipes.

Decoration of ferrous metals

Finished products made of ferrous metals require decorative and protective coatings, the technological qualities of which determine their attractiveness and durability.

When processing ferrous metals, especially by the forging method, a layer of scale forms on their surface, at first glance, a beautiful gray-blue color. But this coating does not protect the metal from corrosion, but is iron oxide.

Having different thickness and density, it is subject to gradual peeling from the main product, so scale must be removed. This can be done different ways. For example, chemically, using a solution of hydrochloric acid, methenamine and potassium iodide in various proportions. Or mechanically - emery, wire brush, fine-grained file, a mixture of water and ground pumice. After cleaning and drying, the product is oxidized by heating its surface with a burner or blowtorch. It produces color tones from yellow to dark blue. Having received the desired shade, the heating is abruptly stopped. Considering the different thickness of the product, oxidation can achieve different color shades on its different parts. After oxidation, the product is coated with wax dissolved in gasoline. After drying, polish with a hair brush. The black color of the metal can be obtained by rubbing the cleaned metal with vegetable oil and heating until a film is obtained. the desired shade. The oil must not be flammable; decomposing from heating, it densely fills the pores of the oxides, forming reliable coverage black or dark brown. Landscape architecture products that are constantly exposed to atmospheric influences are coated with paint and varnish coatings.

Coating with automotive sealant, which is applied to the primer, has worked well. Paint steel in dark blue color can be in an aqueous solution of inosulfite and lead acetate: per liter of water - 150 g of sulfite and 50 g of lead. Coloring occurs more easily when the solution is heated to a boil. This solution gives brass a silvery blue tint.

The austere beauty of blued steel is known, when the metal acquires a blue-black color, like a raven’s wing. At the same time, bluing is one of the best ways to protect against corrosion. Along with silver polished to a mirror surface and shot gold, blued iron was revered as a heraldic metal. These are the types decorative processing were used to create coats of arms, as well as artistic royal or princely weapons.

To obtain black steel with a blue tint, 100 g of potassium dichromate is dissolved in a liter of water, commonly called chromium by craftsmen. The steel product is kept in this solution for 20 minutes and dried over a flame or high temperature heat. A gray-brown tint appears. By repeating bluing, a blued color is achieved.

A black matte surface is also obtained by chemical oxidation in a solution of the following composition: per liter of water 80 g of sodium hyposulfate (potash), 60 g of ammonium, up to 7 g of orthophosphoric acid, 3 g of nitric acid.

Dark- Brown color metal is obtained by oxidizing 15 g of ferric chloride, 30 g in a liter of water iron sulfate and 10 g of copper nitrate. The metal begins to change color to brown. Repeated oxidation will result in a thick black-brown color.

Oxidation at room temperature lasts up to an hour, with heating of the oxidizing solution - it is reduced by three times.

The blue color of steel is obtained by oxidizing in a solution of 120 g of water, 30 g of ferric chloride, nitric mercury, hydrochloric acid and 120 g of alcohol; at a temperature of 20 degrees, the oxidation time takes 20 minutes.

Before any method of oxidation, the oxide layer must be decapitated with chemical solutions (3-5-pro-resin solution in water, hydrochloric or sulfuric acid), and also cleanly degreased with acetone or gasoline. These operations are to avoid grease stains or other surface contamination. Products are treated in solutions on wire hangers and washed under running water to wash off the acid.

In addition to chemical oxidation, they also use the thermal method of decorating ferrous metals, as well as non-ferrous ones, from which products are made intended for use in a dry room.

When the product is heated gas burner shades of tarnish (color variability) change on it - from straw to black. At the required color, the master stops thermal tinting of the metal. For oxidation by heating the surface of a product in an individual workshop, a simple gas burner with a wooden handle connected flexible hose With gas canister. You can make such a burner yourself. A homemade burner consists of a nozzle, a plug and a capsule (as in a burner gas stove), tubes and handles. The easiest way to make a nozzle (with internal threads) and a plug (with external threads) is from brass. lathe. Holes for air supply are drilled in the side of the nozzle. In the plug that connects to the nozzle with a thread, two holes are drilled and threads are also made in them for the tube and capsule. The handle is put on and secured to a tube, which is connected to a flexible hose with a thread. The supply (strength) of the gas flame is controlled by a tap on the cylinder. When working with a gas burner, precautions are necessary: ​​you need to ensure that no collateral fires occur, no gas leaks, and no explosion or fire hazards arise. The color scheme, toning, and color transitions can be achieved by skillfully using a burner. In this way, both embossed and other products or works of mixed techniques are tinted. After heat treatment products are covered with a wax layer (wax with a solvent) and polished with felt and felt.

Olifoil-oil firing is usually used to apply a decorative and protective black-brown coating to cast iron products produced by casting - sculptural works, figured gratings for fencing parks, flower beds, and others. The products are moistened with drying oil and then calcined. This method of decoration is also used for works created by artistic forging, since in blacksmithing, when working with ferrous metals, the master often encounters rust. Depending on the degree of damage, rust is removed mechanically or with solvents of appropriate intensity. Partially affected areas of the metal are cleaned with emery, having previously moistened them with kerosene. Rust that has covered a large area is removed with a solution based on phosphoric acid, the content of which determines its intensity. The solution is applied with a prepared swab on a holder, and after drying, the rust area is treated with an iron brush.

Recipes for solutions of various concentrations

Weak: in a liter of water 15 g of concentrated phosphoric acid, 5 g of butyl or ethyl alcohol;

Average: 700 g of water, 200 g of phosphoric acid, 160 g of technical alcohol, 70 g of washing powder.

Strong: per 100 g of water 275 g of phosphoric and 15 g of tartaric acids, 6 g of potassium nitrate, 3 g of chromic anhydride, 8 g of zinc phosphate and 3 g of thiocarbamide.

To remove rust from works of artistic value, gentle solutions are used for their restoration that can remove rust and minimally damage the main part of the restored product. The preparation of such solutions is possible in a private workshop. This is an almost natural, minimally chemicalized preparation, which is prepared using a 5% solution of hydrochloric acid from crushed leaves and stems medicinal herbs- celandine, marshmallow, yarrow, as well as tomatoes and potatoes.

The acidic solution should cover the crushed herbal mass. Covered with a lid, this tincture is aged for 7-10 days. After this, prepare a solution for etching rust by mixing 5 g of the extract obtained as a result of infusion, 40 g of concentrated hydrochloric acid and 75 g of water. These proportions, if necessary, can be easily changed to obtain an even more gentle etching solution: 10 g extract, 20 g acid, 100 g water (inversely proportional change).

Protective tinting of non-ferrous metals and alloys

Copper and its alloys: brass and bronze are especially susceptible to tinted coatings.

Black (gray) color of copper and brass can be achieved using different oxidizing solutions.

Sulfur liver is obtained by fusing one part of powdered sulfur with two parts of dry potash in a porcelain cup for 15-20 minutes. When reacting with air, the components of the melt interact. Store sulfur sintered with potash longer in large pieces - the activity of this sintering is better preserved - in dark glass vessels, hermetically sealed. An aqueous solution of liver sulfur (potassium polysulfide, also used for oxidizing silver in order to give it a stable sulfide film) is prepared from 10-15 g of liver sulfur per liter of water (store for no more than a day). The product is tinted by immersion in the solution by dipping it with a rag, then the application of the solution to the product is easier to control, and, therefore, to regulate the depth of coloring of the metal surface.

The black color of copper is also given by a solution of the following composition: per 100 ml of water - 0.9 g of sodium hydroxide and 0.3 g of ammonium persulfate - at a temperature of no more than 100ºC.

Old masters carried out blackening of copper according to the following recipe: a solution of copper sulfate is mixed in equal quantities with ammonia (the mixture becomes bright blue), the product is dipped into it for several minutes, then, after removing, it is heated until the copper turns black.

The same procedure applies to the following compositions: a solution of pure copper in nitric acid; a saturated solution of copper sulfate with the same amount of soda carbonate, then after obtaining a precipitate of copper carbonate, the solution liquid is drained, and the washed precipitate is dissolved in ammonia.

Blackening of copper can be done by immersing the product in a solution of ferric chloride in the ratio of one part to one part water.

A gray color is obtained in a solution of 2-3 g table salt and the same amount of liver sulfur in a liter of water.

The most saturated color of oxide films on copper - from light brown to brown-black - can be obtained by preparing a solution in combination of ammonium sulfide with sulfur liver, respectively, in various doses - from 5 to 15 g.

The chocolate color of copper and brass can be given in a solution of potassium chloride, nickel sulfate and copper sulfate - 4.5 g, 2 g and 10.5 g, respectively, per 100 ml of water when the solution is heated to 100ºC.

A brown color with a reddish tint is obtained in a solution of 2.5 g of antimony pentasulphide in a liter of 4 percent sodium hydroxide.

The red-brown color of brass is given by an aqueous solution of zinc chloride and copper sulfate in an equal proportion of parts of zinc and vitriol.

Brown and black colors on brass are obtained by treating the product with a solution of 60 g of hyposulfate and 5 g of nitric, sulfuric or hydrochloric acid in a liter of water. This solution has a toning effect for only 20 minutes.

Olive and black-brown color will be given to brass by treatment with a solution of copper oxychloride and ammonia.

Brass turns black in the following solution: in a liter of water, mix 2 tablespoons of copper oxychloride with two-thirds of aqueous ammonia; This solution must be quickly stirred and sealed. The result will be a mixture of greenish color, and after precipitation - blue-green; brass is tinted in this solution; At the same time, the alloy does not lose its shine. The processing time does not exceed a few seconds.

A solution of 5 g of potassium sulfide in a liter of water will turn a brass product orange-red in a few minutes.

In the old days, brass was given other colors that seemed completely unexpected for this alloy.

The purple color was obtained by immersing the product in a solution of antimony chloride; chocolate brown - fired with iron oxide and then polished with a lead sheen.

The color of antique patina can be given to works made of copper, bronze and brass by treating them in a solution of 50-250 g of ammonium chloride and 100-250 g of ammonium carbonate per liter of water. It is also possible to do this with the following composition: 64 g of ammonium chloride, 132 g of medium acetic acid salt and copper and a liter of 5 percent acetic acid.

A gray-green tint is created with a solution of five components: 50 g of liver sulfur, 75 g of ammonium chloride, 50 g of ferrous acetic salt, 60 g of ammonium, 35 g of 5% acetic acid per liter. The black-green color is obtained by replacing iron acetate with copper acetate.

A blue-green color close to malachite will be created by the following solution: 40 g of ammonium chloride, 160 g of sodium chloride, 120 g of potassium tartrate and 200 g of copper nitrate.

The azure color of brass will be given by a few minutes of exposure to a solution of 3 g of lead acetate, 6 g of hyposulfite (sodium thiosulfite) and 5 g of acetic acid in 100 ml of water at a temperature of 80ºC.

Copper will turn green in a solution of 20 g copper nitrate, 30 g ammonia, 40 g of ammonium carbonate, the same amount of sodium acetate in 100 ml of water (sodium acetate is a mixture of soda and vinegar).

Ammonium in an individual workshop can be tinted in several ways. We will describe those available to a private craftsman, since electrochemical processing of this metal requires special equipment.

The product, pre-treated with alkali (caustic potassium or sodium), is washed and treated in potassium tartrate with alkali, then immersed in a solution of 130 g of copper sulfate or 5 g of zinc chromate, 3-5 g of nitric acid and 15 g of zinc fluoride, mixed in liter of water; aluminum acquires a color from yellow to golden.

There is also a method for tinting aluminum in a golden color. Aluminum coated with a layer of molten paraffin is burned with a blowtorch.

Sometimes the product is rubbed with drying oil or vegetable oil and held over a smoking torch made of roofing felt or roofing felt, which emit resinous soot, the particles of which are firmly connected with hot drying oil, forming a sulfur-colored coating, and the flame should not touch the metal.

Products rubbed with drying oil or vegetable oil are also tinted by calcination. The resulting shiny film of a certain color will reliably protect the metal from corrosion and give the aluminum a piquant decor.

Products coated with vegetable oil will gain olive color, drying oil - red-brown or brown-black.

The easiest way to tint aluminum while protecting it from corrosion is to coat the products with oil paints. Variation color range here is the richest. But this method is only applicable for aluminum.

But calcination is used to decorate steel and cast iron.

Lead is painted gray (dark gray) with citric or acetic acid using a swab on wooden stick. Typically, small products are made from this metal and its alloys, garth and babbitt, by casting. The product, painted to the desired tint, is washed under the tap and dried.

It is known that some plants (herbs) contain various acids in their juice. So, celandine juice contains more than 4 percent organic acids, including lemon, as well as chelidonic, apple and amber; When it gets on the skin, it causes irritation and burns. Celandine juice is used for blackening small products from various metals, including lead and zinc.

Zinc tinting is carried out in different colors due to good reaction with other substances giving colored compounds. Zinc is engravable, good for casting, and, as already mentioned, conveniently tinted. Zinc is given, among other decors, the appearance of old silver.

Gray color is obtained with weak acid solutions. For example, a teaspoon of citric acid and the same amount of copper sulfate per glass of water. “Limonka” can be replaced; the color is given by treatment with a solution consisting of 1 part tartaric acid, 2 parts soda and 1 part water. This solution is mixed with clay, coated with the product, and after drying, washed in water.

The brown-bronze color is obtained by combining 1 part verdigris and 5 parts acid. The surface is also rubbed with the mixture, dried and washed off.

Wetting with vitriol gives zinc its copper color, since zinc is more active than copper.

If you wipe zinc with hydrochloric acid and sand (as an abrasive for preparatory cleaning), and then dip it in a solution of 3 parts of wine-copper salt, 4 parts of caustic soda and 48 parts of distilled water at 10 degrees, then, depending on the residence time of the zinc in solution, you can get completely different colors on it: 2 minutes - purple, 3 minutes - dark blue, 4-5 minutes - golden yellow, 8-9 minutes purple-red.

The blue color of zinc can also be obtained by a solution of 6 g of nickel sulfate and the same amount of ammonium chloride in 100 g of water.

Zinc turns green in the following solution: 10 parts of copper sulfate, the same amount of tartaric acid, 12 parts of water plus caustic soda dissolved in water (1:15) - 24 parts.

Zinc can also be made black; To do this, the metal must be treated with a solution containing the following components: 2 parts copper nitrate, 3 parts copper oxide, 8 parts hydrochloric acid and 65 parts water.

Using these methods, you can tint (paint, patina) not only pure zinc, but also galvanized iron.

And in conclusion, the section on decorative metal trim. If necessary, highlight some fragments of the embossed relief, details of a sculptural metal work or products made in a different technique artistic treatment metal, these parts are wiped with a swab of fine brick powder (as a fine abrasive that removes oxide contamination), moistened with a tinting solution to create an initial tint - an even, ideal, clean layer of primer. This method is especially suitable for finishing relief products.

There is no point in trying to achieve a completely black (opaque) film: no matter what color the coating is, the metal should still seem to be visible through it, hinting even through the decor at its original appearance.

Your name "cuprum" received copper from the island of Cyprus (Surg), where it was mined by the ancient Greeks and Romans. Copper has a characteristic red color; on matte surfaces it takes on a peculiar pink tint, soft, muted. Polished copper is more bright color and shine.

When adding copper to alloys in large quantities they also come in warm reddish tones such as tombac and bronze. Alloys containing a smaller percentage of copper have yellow and greenish-yellow colors; an alloy containing 50% copper and 50% tin and is white in color. Copper-based alloys are made that have a reddish-colored yellow, very closely resembling gold - the so-called French gold.

Copper- soft and malleable metal; it is easily processed by pressure and drawing. Copper is easy to stamp, shape and mint. It easily takes on a wide variety of shapes and allows for high relief carving. Copper rolls well; The thinnest sheets and tapes (foil) are made from it, the thickness of which is no more than 0.05 mm, and various tubes, rods and wire; Moreover, the wire diameter can be adjusted to just 0.02 mm. However, due to its viscosity, copper is difficult to file, it picks up and quickly clogs the file (especially a personal file). Processing of pure copper cutting machines is also difficult - it is difficult to sharpen, drill and mill.

Copper can be finely processed, ground and polished well, but due to its low hardness, parts made of polished copper quickly lose their shine. Copper density 8.94; elongation 45-50%; copper has very high thermal and electrical conductivity; its melting point is 1083°C; boiling point 2305-2310°C. Copper is cast poorly even at high temperatures; pure copper remains thick, mushy and does not fill the mold well. In addition, molten copper greedily absorbs gases, and the castings are porous.

Copper does not oxidize in dry air. When heated above 180°C, as well as under the influence of water, alkalis, acids, etc., copper oxidizes; Moreover, oxidation sometimes occurs very vigorously, for example in strong nitric acid. On outdoors products made of red copper are quickly covered with a film of green copper oxides and black copper sulfur compounds. This film protects the copper from further corrosion in depth. Copper is extracted from ores.

The following impurities are present in copper: oxygen, bismuth, antimony, lead, arsenic, iron, nickel, sulfur, tin, zinc. The most harmful of these impurities is bismuth, which causes red brittleness of copper in the range of 400-600°C. At this temperature, heated copper becomes brittle and unsuitable for processing by stamping, rolling and other methods. With further heating, the brittleness disappears.

In the artistic industry, pure, or red, copper is used quite often, but still not as widely as its alloys - bronze and brass. The use of pure copper in a number of cases is due to its exceptionally high ductility and viscosity, which allows sheets of relatively small thickness ( 0.8-1.2 mm) obtain complex three-dimensional shapes by punching.

In addition, copper is highly resistant to corrosion. Products made of pure copper are perfectly preserved in the open air without any painting or other anti-corrosion coatings, for example, the chased copper door of the Turkmen pavilion at VDNKh (Fig. 7). These properties of pure copper made it the main material for diffusion work in the manufacture of large sculptural and ornamental compositions for the exterior. An example of such copper-hammered sculptures are numerous statues and decorative figures early XIX c., decorating various buildings of Leningrad (Apollo’s quadriga at the former Alexandria Theater).

In addition to stamping production, pure copper is used for stamping very high and complex reliefs and ornaments, for which brass is not ductile enough. Red copper still remains an indispensable material in the field of filigree works of a mass nature. Red copper wire, used for filigree work, in the annealed state becomes so soft and flexible that you can easily twist all kinds of cords from it and bend the most complex fancy ornamental elements. It can be made of any thickness. In addition, red copper wire (due to its refractoriness and thermal conductivity) is very easily and well soldered with hard silver solder, and is well silvered and gold-plated.

Due to these properties (refractoriness and thermal conductivity), as well as certain expansion coefficients when heated, red copper is an indispensable material for art products(filigree or embossed) followed by enameling. The coefficient of linear and volumetric expansion during heating of red copper is very close to the same coefficient of hot enamels. Therefore, when the product cools, the enamel adheres well to the red-copper product and does not crack or bounce off.

Anodes made of red copper of the highest grades are the main material for the production of artistic galvanoplastic works, as well as for the electroplating of copper sublayers during nickel and chrome plating of steel products, since chromium and nickel deposited directly on the steel surface do not hold firmly.

Due to its high thermal conductivity, red copper is an indispensable material for the manufacture of soldering iron cores. Finally, the high electrical conductivity of copper (it is second only to silver), resistivity, equal 0.0175 Ohm*mm 2 / m, caused the widespread use of copper for the manufacture of conductors electric current- wires, cables, etc.

Copper is the main component of hard solders (copper, silver and gold) used for soldering a wide variety of art products, ranging from jewelry to large decorative objects. In addition, copper, along with gold and selenium, is used to make colored red glass (copper ruby), enamel and smalt. Large quantities of copper are used to prepare alloys.

Copper alloys. Alloys of copper and zinc are called brasses; all other copper-based alloys are called bronzes. In addition, copper is added to special steel alloys.

Brass. Most brass has a beautiful golden yellow color. Artistic brass products coated with special colorless or lightly colored alcohol varnishes or nitro varnishes acquire and retain the appearance and shine of gold for a long time. Brass is used to make unique decorative items (Fig. 8). Brass is also used for haberdashery and cheap jewelry, followed by silvering or gilding.

Brass is well processed on cutting machines, polished and retains a polished surface for a long time, welds and solders well with both soft and hard solders. Most brass is well rolled, stamped and minted. Brass is easily and durablely plated with a variety of electroplating coatings - nickel, silver and gold; It accepts chemical oxidation well and can be tinted in any color. The melting point of brass is 980-1000°C. Most brasses cast poorly, but there are special grades of foundry brass, for example aluminum brass (LA67-2.5), which, due to the admixture of aluminum, has good casting properties and, in addition, differs from other brasses in its high corrosion resistance. Manganese-lead brass (LMtsS 58-9-2) and some other types also have foundry properties.

Compared to pure copper, brasses are stronger and harder, and some of them, for example brasses containing about 30% Dink (L68), are not inferior to pure copper in terms of ductility. In Fig. Figure 9 shows a fragment of embossed sheet brass of this brand. In addition, brass is much cheaper than copper (since zinc is cheaper than copper) and is much more beautiful in color than red copper.

Brass with a low zinc content - from 3 to 20% (grades L96, L90 and L85) are called tombaks; They are distinguished by a reddish-yellow color and are used for the manufacture of artistic tableware, as well as in the artistic enamel industry for the manufacture of sports and anniversary badges, as well as cheap jewelry. Tompak is well processed in a cold state - it is stamped, drawn into wire, approaching pure copper in this respect. In the open air, products made from tombak gradually darken, becoming covered with an oxide film.

Alloys that were especially widely used in the 19th century are very close to tombak. in Western Europe and Russia as “fake gold” for the production of cheap jewelry. They consist of copper with small impurities of zinc (up to 18%) and tin, which improves their casting properties. These alloys had loud, fancy names, for example, “Similor”, “Oreid”, “Chrysochalk”, “Chryzorin”, “Prinzmetal”, etc. Currently, they have gone out of fashion and have lost their significance.

Currently, in the domestic jewelry industry, interest in non-precious alloys that imitate gold and silver has revived.

In table Figure 12 shows some of the alloys that are undergoing industrial testing (or are already in use).

The last three alloys are identified as the most appropriate for implementation. They have a favorable combination of mechanical and chemical properties, satisfactory corrosion resistance, etc.

Brass is available in the form of sheets of various thicknesses, strips, wire rods and tubes. Foundry brass is produced in the form of ingots (pig brass). It should be noted that most brass assortments cannot be stored for a long time in cold, unheated warehouses, since changes in temperature, humidity and other conditions destroy brass.

Artwork made of brass “works” well indoors in warm and dry rooms. In the open air, brass quickly loses its shine and golden color, becomes covered with sulfur and oxide films, turns black and loses its artistic qualities. Therefore, it is not advisable to use brass for exterior artistic products; Bronze is used for these purposes.

Despite the fact that zinc was discovered only in the 16th century, brass was already known to the ancient Romans. They obtained it by alloying copper with galmey, that is, with zinc ore, which contains a mixture of carbon-zinc and silicic acid salts. It was believed that galmey has the property of coloring copper yellow, but until the end of the 17th century. It was not known that brass was composed of copper and zinc. This method of preparing brass was also used in the Middle Ages and survived until the 19th century. By alloying copper with the metal zinc, brass was first produced in England in 1781. Currently, brass is produced by alloying copper with zinc.

From the middle of the 18th century. They began to produce “bronzing powder” from brass for bronzing artistic products made of plaster, wood, papier-mâché, as well as using it for printing wallpaper and for other purposes. It was obtained by mechanically grinding the thinnest brass plates, previously rolled and flattened under a steam hammer to a thickness equal to several microns.

Bronzing powder is also obtained in another way - by reducing a solution of copper sulfate metallic iron. The resulting spongy copper mass is crushed, washed and dried, and then given a bronze tint by heating with paraffin in iron boxes until tarnish appears.

Bronze. Bronzes have been known to mankind for a very long time, several thousand years BC. In the history of the development of human society an entire era is called the "Bronze Age". During this era, man for the first time learned to smelt bronze from copper and tin ore and produce household items and weapons from it, and later coins and various jewelry. In all the most ancient centers of human culture - in Egypt, China, India, in the art of the ancient Assyrians, Etruscans, Greeks and Romans, there are monuments of art made of bronze. Already in the seventh century BC, ancient artists learned to cast bronze statues, for example, the bronze figure of the “Delphic Charioteer”, cast in 470 BC. e. (Fig. 10).

Rice. 10. Bronze figure of the "Delphic Charioteer" 470 BC. uh

The composition of the most ancient bronzes, dating back to the Bronze Age, included approximately 88% copper and 12% tin. Antique, or Corinthian, bronzes contained even more copper - up to 90%. In addition, they often contained iron, cobalt, nickel, lead, zinc, and silver as impurities. This is explained by the fact that bronze was obtained by smelting copper and tin ores, which always contain impurities of various metals. Byzantine and Korsun bronzes, as well as Old Russian bronzes of the 9th-10th centuries. were very close to the ancient ones. They contained no more than 8-10% tin, and the rest copper.

In the XII-XIV centuries. V Ancient Rus' castings were made from an alloy of copper, tin, zinc and possibly lead, called "Spruda".

In the XV-XVII centuries. castings were made from red copper with tin, and from the 18th century. from yellow copper - bronze with the addition of zinc. From the middle of the 19th century. For the casting of monuments, the so-called “Sukrasnaya” bronze was used, which included a zinc alloy (up to 5%). About 70 different monuments were cast from this bronze at the St. Petersburg Bronze Casting Factory A. Morana: monuments M. I. Glinke in Leningrad and Smolensk, I. K. Aivazovsky in Feodosia, N.V. Gogol in Moscow in the courtyard of a house on Suvorovsky Boulevard, I. Kruzenshtern in Leningrad, etc. late XIX V. wide application For artistic casting, bronze containing 2-4% tin and 10-18% zinc was obtained.

In Western Europe, bronzes close to this composition were used for statue casting. For example, in France bronze was used, consisting of 82% copper, 13.5% zinc, 3% tin and 1.5% lead.

Currently, casting of artistic products is made from special artistic bronze. GOST includes three grades of bronze of the following composition (Table 13).

In addition to zinc and tin, these bronzes contain a small admixture of lead, and the rest is copper.

Ancient bronzes were an alloy of two components - copper and tin (except for occasional impurities). However, using bronze, consisting only of copper and tin, for casting large figures and statues has a number of disadvantages. Such bronze has a dense melting point and does not fill the mold well; it is expensive and difficult to cut. In addition, with the most common tin content ranging from 7 to 15%, the alloy is easily subjected to segregation, i.e., with slow cooling, the alloy separates, the part with a high copper content solidifies earlier. Liquation is further enhanced if lead is present in the bronze (over 3%).

Liquation is a big hindrance when casting large monuments, as it negatively affects the finishing and oxidation of the finished figures, as well as the appearance of a natural patina. Segregation can be prevented by adding small amounts of zinc, phosphorus and some other components to the alloy, as well as by rapidly cooling the casting. However, excessive additions of zinc negatively affect the color of bronze and its ability to develop a natural patina.

Bronze color with magnification percentage tin changes from red with a copper content of at least 90%, to yellow with a copper content of at least 85%, white with 50% and steel gray with a copper content of less than 35%.

Modern artistic bronzes are a material for casting monuments and monumental sculptures. In northern climates, bronze is an excellent material, extremely durable, unaffected by weathering and resistant to mechanical damage, as well as resistant to frost. In terms of its color qualities, bronze looks equally good both in open space in a city square and in the greenery of a square or park.

Along with products for the exterior, bronze is widely used for casting highly artistic decorations. public interiors- theaters, palaces, halls, for example, large chandeliers, sconces, candelabra, floor lamps and other items.

Since the 18th century. gilded bronze appears. Chandeliers, candelabra, floor lamps, decorative vases made of gilded bronze in combination with cut crystal, polished stone and colored glass played an important role in the overall artistic design of palace interiors (halls of the Kremlin Palace, Hermitage, etc.).

In addition to tin bronzes, our industry currently produces special tin-free bronzes. These alloys do not contain tin - it is replaced by aluminum, zinc, lead, silicon, nickel, manganese and other elements. Tin-free bronzes are distinguished by a number of new mechanical and technological properties and in many respects are significantly superior to tin bronzes. For example, manganese bronze has high heat resistance; silicon bronzes with the addition of nickel or beryllium bronzes have the property of being hardened and are not inferior in strength to steel. However, in the field of the artistic industry they are almost never used, but are used for the manufacture of various parts for technical and special purposes.

Dyeing copper items reddish brown.

To paint the surface of copper things in a beautiful and durable reddish-brown color, the following composition can be used: 4 parts by weight of copper acetate (verdienne), 4 parts of crocus and 1 part of horn trimmings. Crush thoroughly and mix with enough vinegar to form a paste. Having lubricated the surface of the thing with this composition and allowed it to dry, the thing is heated until the composition turns black; After this, it is washed off and the item is polished - a beautiful reddish-brown color is obtained. If you want the color to be dark chestnut, then add 1 part of copper sulfate (in powder) to the above mixture; for a lighter, yellowish (bronze-like) coloring, instead of copper sulfate, add 1/2 - 1 part of borax.

Coloring of artistic copper products.

Artistic copper products (figurines, medals, etc.) are best painted with one of the following compositions:

1. Boil 32 parts by weight of copper acetate (verdigris) in powder, 30 3/4 parts of crushed ammonia and 1 part of strong vinegar with 20 parts of water. Give after boiling. stand and carefully drain the clear solution without sediment, into which to immerse things for 1/4 hour.
2. 5 parts copper acetate (crystalline), 7 parts ammonia, 3 parts acetic acid and 85 parts water. Highly heated over fire charcoal Immerse the copper item in the solution. When the item is painted, take it out, rinse, dry and rub with a solution consisting of 1 part wax and 4 parts turpentine.
3. Boil 2 parts by weight of ammonia, 1 part of table salt, 1 part of saltpeter, 1 part of strong ammonia with 96 parts of strong vinegar and immerse things in the boiling solution, keeping them there until they are properly colored. Having taken it out, rinse first in a hot solution of ammonia in water, and then in boiling water.

If things are inconvenient to immerse in solutions, then they can be lubricated with a sponge moistened with these solutions; but you need to lubricate evenly and, most importantly, quickly, otherwise the coloring may turn out to be spotty.

You can also lubricate things with liquid gruel prepared from 2 parts copper acetate, 2 parts cinnabar and 5 parts ammonia with the right amount vinegar. Oiled items are heated, washed and dried several times until the coloring takes on the desired shade.

Painting things made of real bronze.

To dye things made of real bronze (i.e., an alloy of copper and tin) brown, it is better to use one of the following solutions;

1. 4 parts ammonia, 1 part potassium oxalate and 200 parts vinegar. Things are lubricated with this composition and allowed to dry. This operation is repeated until things acquire the desired color. The rather sharp metallic gloss remaining on things after this soon disappears, and they receive that pleasant soft brownish color, which under ordinary conditions forms on bronze only after several years (patina).
2. 1 part crystalline copper acetate, 1 part ammonia and 200 parts water. After smearing the surface of the item with this composition, dry it over the fire until the green color begins to disappear. Dilute the above composition with another 340 parts of water and lubricate the item with this diluted solution another 10-15 times, each time drying it over the fire. This diluted composition can be prepared separately: 1 part copper acetate, 2 parts ammonia and 600 parts water. This is even necessary if you want to operate on many things sequentially. After the first smears, the color has an olive green color, but then it gradually takes on a more and more pleasant color. brown tint, which does not disappear even from very strong heating of things.

Painting copper, brass and bronze items.

Copper, brass and bronze items can also be painted a very beautiful brown color using a solution of bismuth in strong nitric acid: after immersing the items in this solution, they are kept over the fire until the desired brown color is achieved.

Bronze(chemical). - This is the name for alloys of copper with tin in various proportions (copper in excess), then alloys of copper with tin and zinc, as well as some other metals or metalloids (lead, manganese, phosphorus, silicon, etc., in small quantities). The presence of foreign metals in real bronze (copper-tin alloys) is sometimes random in nature and is due to the incomplete purity of the source material (some examples of antique bronze), but usually the addition of a certain amount of certain substances is carried out knowingly, for certain purposes, and then such bronze receives special names (manganese bronze, phosphorus bronze, etc.). With the addition of tin, copper becomes more fusible, hard, elastic, and therefore sonorous, capable of polishing, but less malleable, and therefore bronze is mainly used for casting various items. The qualities of bronze depend on the composition, methods of preparation and subsequent processing. If alloys of copper and tin, containing from 7% to 15% of the latter and most commonly used in practice, are subjected to slow cooling, then the alloy separates and the part richer in copper solidifies earlier; This phenomenon, called bronze segregation, is a great hindrance when casting large bronze objects; it can be eliminated to a certain extent by adding certain substances (for example, phosphorous copper, zinc) or quickly cooling the cast objects (conversely, the admixture of lead causes an easier separation of the alloy, so the addition of this latter above 3% should be avoided). When bronze is hardened, a phenomenon occurs that is completely opposite to that observed for steel: bronze becomes soft and, to a certain extent, malleable.

The color of bronze, with increasing percentage of tin, goes from red (90% - 99% copper) to yellow (85% copper), white (50%) and steel gray (up to 35% copper). As for ductility, at 1% - 2% tin alloys are cold forged, but less than pure copper; with 5% tin, bronze can be forged only at a red-hot temperature, and with a content of more than 15% tin, malleability completely disappears; alloys with a very high percentage of tin again become somewhat soft and tough. Tensile strength depends partly on the composition, partly on the state of aggregation determined by the cooling method; with complete homogeneity and the same composition, bronze with a finely crystalline structure has greater resistance. The specific gravity of bronze is usually greater than the average specific gravity components, and changes from forging and more or less rapid cooling. According to Riche's research, the alloy corresponding to the formula SnСu3 has the highest specification. weight 8.91 (hence, during its formation the greatest compression occurs); its structure is crystalline, its color is bluish; with slow cooling it remains completely homogeneous; there appears to be a certain chemical compound involved. The SnCu4 alloy has similar properties. Under the influence of humidity and carbon dioxide in the air and similar reasons, over time, bronze sometimes develops an excellent bluish-green coating, or a layer of basic copper salts, so valued in bronze objects by connoisseurs and called Aerugo nobilis, Patina, Verde antico. Patina protects the bronze from further alteration; whether the composition of bronze has an effect on the speed of its appearance is a controversial issue; It is known that the formation of patina can be accelerated artificially, but only to the detriment of beauty. Not long ago, the question was raised about the fact that bronze statues in big cities (London, Berlin) either directly turn black, or the green patina that has formed on them gradually acquires a darker, almost black color. A commission assembled on this occasion in Berlin decided that this phenomenon depends on the smoky and dusty atmosphere big cities, where buildings are heated primarily with coal containing sulfur compounds. To preserve statues, it is recommended to clean them with a solution of spermaceti in gasoline.

Antique bronze was known much earlier than brass; in very distant times, it is known to have been used for making weapons, coins, various jewelry, etc. ( bronze age). Bronze was then obtained by smelting copper and tin ores, and therefore antique bronze often contain, as impurities, iron, cobalt, nickel, lead, zinc, silver, etc. The most ancient bronze, golden in color, contains approximately 88% copper and 12% tin (F. Wibel, “Die Cultur der Bronzezeit Nord- und Mittel-europas", Kiel, 1865).

Cannon or artillery the metal consists (in round numbers) of 90 -1 parts of copper and 9 - 10 parts of tin (also sometimes containing small amounts of zinc and lead). Alloys with this composition are very prone to segregation. Ud. the weight of artillery metal containing 10% tin is 8.87. Bronze for tools must be hard, tough, elastic, have high tensile strength and possible indifference to chemical agents; Alloys of the specified composition satisfy these requirements, but only to a certain extent. The so-called Uchatzius steel bronze (Stahlbronze) contains 8% tin. To increase tensile strength, such bronze is subjected to strong pressure, using a hydraulic press to drive a steel cone of larger diameter into the drilled mouth of the gun.

Bell metal differs from the previous one in its high tin content; its average composition: 78% copper and 22% tin; beat weight 8.368. The silver content in some bells is an accidental or excessive admixture: it is mistakenly thought that silver increases the sonority of the bells. An alloy of copper and tin of the specified composition has all the properties that can be required from a good bell, i.e. sonority, sufficient hardness and strength (resistance to tearing). When fractured, it is fine-grained, yellowish-gray in color), fusible, and fragile. The known tone of a bell depends on its shape, casting and composition. The alloys used for the manufacture of musical percussion instruments and for the Chinese tam-tam or gong-gong have a composition similar to bell metal. The special sonority of Chinese instruments is achieved by rapid cooling of the alloy (hardening) and prolonged forging.

New statue bronze. The use of casting bronze consisting only of copper and tin, in addition to its comparative high cost, presents quite a few other inconveniences: such bronze is quite difficult to melt, is not so well cast into a mold, and when solidifying is easily subject to segregation, which has an unfavorable effect on the appearance of the cast objects and on the formation of a uniform layer of copper salts (patina); Moreover, it is difficult to process with a cutter. These inconveniences can be eliminated by a certain change in the composition of bronze, and therefore, at present, when casting statues, part of the tin in bronze is replaced with zinc. Alloys with 10% - 18% zinc and 2% - 4% tin are distinguished by a beautiful reddish-yellow color, perform well in the slightest indentations of the shape, are sufficiently tough for processing and gain from action atmospheric influences beautiful green coating (patina). A higher tin content makes bronze too brittle, and from an excessive addition of zinc it loses its color and becomes unattractive. dark coating metal compounds. From the admixture of lead, bronze becomes more capable of processing, but already at quantities above 3%, the alloys are very easily subject to segregation. According to D'Arce, bronze consisting of 82% copper, 18% zinc, 3% tin and 1.5% lead is most suitable for casting statues. Normal Elster bronze contains 862/3% copper, 62/3% tin, 31/ 3% lead and 31/3% zinc.

Phosphor bronze, proposed by Künzel in 1871, consists of 90% copper, 9% tin and 0.5% - 0.5% phosphorus; used for casting cannons, bells, statues, bearings, various machine parts, etc. The addition of phosphorus (in the form of phosphorus copper or tin) increases bronze's elasticity, tensile strength and hardness; The molten metal is easy to cast and performs well in the recesses of the mold. By changing the weight ratios of the constituent parts, you can give the alloys the desired properties: make them soft like copper or tough like iron, and hard like steel; the structure of phosphor bronze does not change from blows and shocks; when the phosphorus content is over 0.5%, its color is golden.

Aluminum bronze- alloys of copper and aluminum, containing from 5% to 10% aluminum and 90% - 95% copper. The color of bronze, with a content of 5% aluminum, is very similar to gold; besides beauty, it is distinguished by many other excellent qualities (by the way, alloys with 8% - 5% aluminum are very malleable). There are five grades of aluminum bronze available in the trade, with varying degrees of ductility and resistance to tearing; it resists oxidation and seawater well, much better than other alloys. The silicon impurity changes the color and properties of aluminum bronze. As a material for the manufacture of various parts of machines, it replaces phosphorus bronze in paper mills and gunpowder factories ("Jahresber. ub. d. Leist. d. chem. Technol.", 1890, 359).

Flint Bronze It has the same tensile strength as phosphor bronze and is characterized by high electrical conductivity; it is used for telephone wires. Weyler flint bronze (for telephone wires) contains, according to Gampe's analysis, 97.12% copper, 1.62% zinc, 1.14% tin and 0.05 silicon.

Manganese bronze is obtained by alloying manganese cast iron (ferromanganese) with copper, then with copper and zinc or with copper, zinc and tin. The Crown Company in England produces five grades of it, which differ from each other in their properties (hardness, viscosity, tensile strength) and are used for various purposes (Heinzerling, "Abriss d. Chem. Technologie", 1888).

In addition to these types of bronze, there are other alloys that have various applications; such as, for example, bronze for mirrors, medals, coins, bearings and various machine parts, etc.

Metal is widely present in our premises, and is used where its uniqueness compared to other materials is needed physical qualities. However, metal often also decorates the living area with its presence. And in order to make its visual characteristics even more interesting, the metal surface can be given a particular color or texture. Metal painting itself is most often done with defensive purposes, however, technology decorative painting has a lot of differences.

Coloring with decorative properties Most often, various metal objects, lamp caps, heating radiators, sinks and similar elements are affected. In this case, work can be carried out both on objects used indoors and on external metal elements.

Advice for those who are planning to paint a metal surface at sub-zero temperatures

Although this advice may apply more to ordinary painting than decorative painting, situations are different. For example, you need to immediately paint a part that has just been brought in from the cold. Therefore, we will give some tips:

• The best way to paint in the cold is to use alkyd enamels with a jelly-like consistency, having high adhesion(ability to penetrate the surface structure);
• Painting of surfaces cooled to temperatures below +5 degrees Celsius should be done exclusively with pre-treatment this very surface with a torch or heat gun. Otherwise, condensation will form on the surface on which the paint simply will not adhere;
• If the room itself is cold when painting, then the drying time of the layer can increase several times, which is especially unpleasant for decorative painting. Therefore, it is recommended to install heat gun, and cover the surface with film.

What are blacksmith paints

Recently, forging paints, specially optimized for working with forged materials, have become very popular. Such paints are applied to forging for decorative purposes, which makes it possible to imitate the most various surfaces, starting from gold and ending with cast iron.

The cost of such paints is higher than that of ordinary ones. However, this is due to their increased shelf life, which reaches 5 years or more. At the same time, such paints also look really impressive, allowing you to give the required visual effect by the very fact of their presence. Without the need for different painting methods.

Today there are many types similar coating, however, the most popular is the German paint WS-Plast, produced by Weigel & Schmidt GmbH. These paints allow you to give metal surfaces a variety of different colors and textures. Here you have emerald color, and graphite with red tones, and different kinds antique colors. Moreover, such a coating not only decorates, but also protects the metal surface from corrosion and other troubles caused by the influence of nature.

Also popular hammer paint(Hammerite), which is currently becoming increasingly popular. The reason is that such paint does not require the application of a primer, and can even be used directly on surfaces damaged by corrosive processes. However, if the rust is loose, then it will still have to be removed. The surface treated with this coating becomes monochromatic with the effect of unevenly shaped patterns and aluminum flakes.

The application of this paint is mainly practiced on ferrous metals such as steel and cast iron. However, it can also process some non-ferrous metals.

How to show patina

Patina is a characteristic greenish coating that appears on the surface of copper and bronze products after oxidation. On this moment in the best possible way This effect can be achieved using WS-Patina paint. In this way, it is possible to age the metal and give it a characteristic respectable shine.

Antique painting

One of the most popular ways to paint black metal is the antique effect. In this case, several coating options are applied to the metal surface in a certain order. But first, the metal itself must be properly prepared. It must be cleaned of corrosion, sanded, and dirt and grease are removed. Only when you are confident that the surface is clean can you begin the process, which is divided into several stages:

• Using a brush, apply metallic paint to the surface. Don't be afraid to do it casually, as this will only help with the effect we are creating;
• Once the first layer has completely dried, it is necessary to apply a craquelure primer. The latter allows you to get a layer transparent film made from polymers;
• The craquelure coating is applied after the primer layer has dried, which makes it possible to obtain characteristic cracks, similar topics that appear on things that have been used for decades and even centuries.

Important! Instead of a craquelure composition, the effect of antiquity can be achieved by applying burnt umber to the paint. In this case, it is best to work with a dry cloth, and remove the residue after the paint layer has dried.

Bronze metal painting

Bronze coating is one of the most visually impressive. Therefore, people often strive to recreate it. And there are several ways to do this, and they all involve the use of bronze paint.

First of all, the surface is prepared. Dirt, grease and rust are removed. After this, a layer of metal primer is applied to it, which will increase the adhesion of the layers applied above. At the third stage, bronze metallized paint is applied in 2-3 layers.

If you want to give this bronze layer the effect of antiquity, then the recesses must be treated with patina, which allows you to get the effect of darkening over time. After this, glazing is carried out, during which we paint over the protruding elements and those places that are characterized by abrasions with white paint. After the latter has dried, a transparent varnish is applied to seal the effect.

Conclusion

Painting for all other types of metals occurs in a similar manner. Modern metallic paints allow you to create the effect of brass, copper, silver, gold and other metals.

Don’t be afraid that you won’t succeed. Practice shows that such methods of metal processing are feasible without any serious knowledge. The video tutorial below will give you comprehensive information on this matter.