Chemical decoration of metal. Gold plating at home: gilding methods How to get gold from copper wire

Today we will look at how you can turn copper into gold. This is not from the field of alchemy and the philosopher's stone has nothing to do with it. This is ordinary chemistry, and, of course, copper will not become gold, in terms of its chemical and physical properties, but will simply take on the appearance of gold. In this way, you can make gold: a copper coin, a copper chain or ring, or any other items,. In order to turn copper into gold, we need the following ingredients: about ten grams of zinc sulfate, a piece of zinc itself, and, of course, for example, a copper coin.

Zinc sulfate must be dissolved in fifty milliliters and put on the stove. We put a prepared piece of zinc there, and then a copper coin. The coin must be in contact with the zinc. Now turn on the stove and boil it all for fifteen minutes. During the boiling process, you can see that the coin is gradually covered with a layer of zinc. How does this happen? Everything is very simple. In the process of boiling, zinc begins to give up its ions, and the solution is overflowing with zinc ions. Copper, like less, attracts the more electronegative zinc ions. So it turns out that our copper coin begins to be covered with a thin layer of zinc.

After fifteen minutes of boiling, remove the container from the stove and take out the coin from there. The coin can be washed in water to make it cleaner. Now in our chemical experiment, we need to carry out the most important "trick". Namely, we turn the resulting silver coin into a gold one. Turn on the electric stove to maximum heat and put, directly on the hot burner, ours. You will see how instantly the silver coin will acquire the color of natural gold. This is due to the fact that the zinc layer, as it were, is absorbed into the copper, and it turns out, supposedly, a layer of gold. At least visually, it will be difficult for an inexperienced person to distinguish your coin, chain or ring from real gold.

Why this chemical experience can be useful to you in practice? Well, of course, not for you to turn copper products into, supposedly, gold, and sell them, thus to inexperienced people, at the price of real gold. This, dear friends, is fraught with a long prison term in places not so remote, popularly called the zone. And it will come in handy, this method can only be for personal use. For example, I have a thick chain made entirely of copper. The chain is well made and looks very nice. But wearing copper around the neck is somehow not very aesthetically pleasing, and besides, a black stripe remains on the skin from long wearing. So, I first made the chain silver. And he wore it with a silver church cross (made of real silver). They practically did not differ from each other. Then, when I got tired of silver, I repeated the procedure, and "fried" the chain on a hot stove. Now I wear, supposedly, a gold chain, almost as thick as a finger. Agree, it’s easier than spending your hard-earned rubles on buying real gold. Although this is also debatable. If, for example, you want to keep your money from being depreciated by inflation, then naturally you need to invest it in something. Why not buy gold things for this? They can always subsequently be sold, unless, of course, they are. Personally, I prefer to transfer money to gold in a bank. And you can wear copper for beauty, after giving it the appearance of gold, in the manner indicated above. Good luck, modern alchemists!

The scope of this coating is amazing, gold paint is successfully used for the restoration of buildings and structures, interior decoration, painting household items, car elements and much more.

What do you need to dye gold at home?

How to paint "under gold" at home?

To paint any object with gold yourself, you need to seriously approach the choice of paintwork materials. The range of gold paints is currently quite wide, so choosing the right shade is not difficult. Gold paint is sold on the modern market in the following forms:

1 Aerosol cans

2 hermetically sealed metal cans

3 Instant mixes

What and how you can paint yourself under gold

To date, the most popular and widely available method of painting under gold are spray paints that perfectly imitate this expensive metal. Spray paints can be applied to absolutely any surface: plastic, paper, glass, concrete, metal, etc. Very often, aerosol enamels are used to change the color of a car, since the paint lays down perfectly evenly when sprayed. It can easily and inexpensively ennoble caps on car wheels, as well as such interior items as picture frames, floor lamps, lamps, cornices, furniture elements, parts of smartphones and laptops ... in general, there are a lot of options for using gold paint.

As for the use of gold paints in spray cans in the automotive sector, small parts, plastic body elements, are usually isolated with gold. Sometimes extraordinary personalities repaint a car completely in gold. The question of how to paint car rims with gold yourself is very popular, because this element painted with gold paint alone can emphasize the general appearance of the car. Today it will not be difficult to find a company that would deal with car tuning, but you can paint wheels with gold with your own hands. Just imagine how unusual and expressive the wheels of a car painted in gold will look like: the paint will shimmer playfully under the sun's rays, and the wheels will look especially impressive while driving. The high demand for aerosol "golden" paint is due to the fact that spray paints can be applied even without preliminary grinding and priming of the surface.

Let's take a look at the main benefits of gold spray paints:

1 Spray paints have excellent coverage and adhesion to almost all materials

2 Fast drying, which allows several layers of paint to be applied in a short time (after painting, it is recommended to apply a layer of varnish to protect the surface)

3 Ease of use at home is one of the main advantages of this coating. In addition, it does not need to be diluted and buy paint brushes

4 The result of spray painting is a perfectly even coating

5 Spray paint in cans is economical

Step-by-step instructions for painting with gold paint at home

Step_1 Clean the surface to be painted from dirt with a sponge (brush) and soapy water. If dust and dirt remain on the product, the paint will lie unevenly and the product will have to be repainted. Dry the surface well before starting work.

Step_2 To degrease the surface, wipe it with a solvent or white spirit, then wash off the applied composition and dry the product thoroughly. Step_3 To create a "rough" structure, if possible, sand the surface with fine sandpaper. Grinding will allow the paint to lie perfectly evenly, due to the bonding of the paint and the porosity of the surface. After sanding, the surface will become slightly matte. Properly selected sandpaper will not give the product unwanted roughness, so it is better to choose sandpaper with a grit of no more than 180. Be sure to remove sanding dust.

Step_4 Before painting the product with gold paint at home, glue the places that cannot be painted with construction tape and a covering film and remove it immediately after the work is completed.

Step_5 Now you can start painting with gold spray paint. Shake the spray in the can for at least 30 seconds, spray the spray paint from a distance of 20-30 cm from the surface. You need to put the paint in smooth uniform movements. After the first layer has dried, which will take 15-20 minutes, apply subsequent layers of paint. When painting "under gold" it is recommended to apply at least 2 - 3 layers of paint.

Step_6 After the spray paint dries, apply varnish in the same way and wait for it to dry. Complete (final) drying takes at least 2 - 2.5 hours. Your golden item is ready to use!

What to pay attention to when painting objects and surfaces with gold?

4 When painting radiators, stoves, fireplaces, etc. for gold, the paint should be not only "gold", but also heat-resistant

5 If you work with an aerosol outdoors, do it in dry and calm weather

6 Once again, we draw your attention to the fact that in order to obtain a more even coating, it is necessary to apply paintwork materials in 2-3 layers. Pause before applying each layer

7 Whenever possible, use paint, primer and varnish from the same manufacturer

8 Do not spray paint near open flames

Summing up, it should be noted that aerosol gold paints have gained really deserved popularity in the last few years, the range of application of gold paint is simply unlimited. They are indispensable for decorating and creating luxurious interiors, finishing small details and painting your favorite gadgets. Gold paint in a spray can has increased brightness and durability, is easy to use and looks great on the product.
Now, after reading the article, you know how to paint any material yourself under gold. Be sure that the product will acquire a bright effect of real gold if you are patient, accurate and creative in your approach to the task!

If this article was useful to you, please rate it (at the top of the page). Thank you!

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By learning how to do gilding at home, which is not as difficult as it might seem at first glance, you will be able to return a second life to your favorite copper and silver jewelry. Products made of gold have been very popular with both women and men for many years. To possess such products without serious expenses for their acquisition, it is enough to master the technology of gilding.

What metals can be gilded?

The most common process is silver plating, but gold plating can also be applied to the surface of other metals. So, gilding can be applied to and zinc, as well as iron and steel, etc.

There is no single answer to the question of how to gild metal at home. It all depends on what kind of metal products need to be subjected to such processing. The choice of gilding technology carried out at home is also influenced by the result to be achieved.

Various methods can be used to gild metal, the most common of which are:

• rubbing the surface of the product with a solution of gold chloride;
• gilding, performed by immersing the product in a solution with a zinc contact;
• electroplating gilding.

Each of these home gilding methods requires the use of certain chemicals, tools and equipment.

Preparation and use of chlorine gold

To cover a metal with a layer of gilding, a solution called gold chloride is often used. To prepare such a solution, gold is dissolved in aqua regia, which is a mixture of hydrochloric and nitric acids. Hydrochloric and nitric acids are taken in a ratio of 3: 1. Gold is placed in this composition, and then the liquid is evaporated. The procedure for evaporating liquid from such a solution should be done very carefully so as not to get burns of the skin and respiratory tract. The dry matter remaining after evaporation is precisely gold chloride.

Before using chlorine gold for gilding, it must be mixed with a solution of potassium cyanide and elutriated chalk, resulting in a mushy mass. Such gruel, using a brush, cover the product, after which it is kept for some time, and then thoroughly washed and polished.

For gilding steel, chloride gold is mixed with ether. The product covered with such a composition is left for some time until the ether completely evaporates, and then the treated surface is simply rubbed with a cloth to give it a golden sheen.

Using chloride gold, previously mixed with ether, various inscriptions and patterns can be applied to a metal object. In order to carry out such a procedure, a quill pen is dipped into the resulting solution and the required inscriptions and patterns are made, which, after evaporation of the ether and polishing, will sparkle with a golden sheen.

As mentioned above, gold plating is often applied to silver, for which chlorine gold can also be used. To perform chemical gilding of products from this metal, it is necessary to prepare a mixture that includes the following components:

• chloride gold - 10 grams;
• potassium cyanide - 30 grams;
• table salt - 20 grams;
• soda - 20 grams;
• water - 1.5 liters.

Chemical gilding to which silver is to be subjected can also be carried out using a mixture of:

• chloride gold - 7 grams;
• ferrous-cyanide potassium - 30 grams;
• potassium carbonate - 30 grams;
• food salt - 30 grams;
• water - 1 l.

The very procedure of deposition of a layer of gold on the metal surface using chemical solutions is performed in the following sequence.

1. The workpiece is pre-calcined.
2. The surface of the object is etched first with a solution of sulfuric acid, and then with nitric acid.
3. The pickled product is momentarily immersed in a mixture of sulfuric, nitric and hydrochloric acids.
4. After treatment in a mixture of acids, the product is rinsed with water, then immersed in mercury and finally in water, where it is kept for 30 seconds.
5. After a container with water, the product is placed in a solution for gilding, kept for the required time, then washed with water and dried in sawdust.

Application of zinc contact

To get a thicker gold layer, a zinc contact is used. This method can, for example, cover silver with a layer of gold. For gilding, a composition is prepared from such components as:

• chloride gold - 15 grams;
• carbonic salt - 65 grams;
• yellow blood salt - 65 grams;
• edible salt - 65 grams;
• water - 2 l.

Products made of copper and brass are covered with gold in a solution of the following composition:

• chloride gold - 2 grams;
• caustic potassium - 6 grams;
• potassium cyanide - 32 grams;
• phosphate-sodium salt - 10 grams;
• water - 2 l.

Objects, on the surface of which it is necessary to apply a layer of gilding, are thoroughly cleaned of dirt and grease, then they are placed in a pre-heated composition for gilding. Products already there are connected to a zinc rod, which acts as a contact.

In order for the gilding applied to the surface of products made of steel, zinc and tin to be of high quality and to have good adhesion, they must be subjected to a copper plating procedure before gilding.

Galvanic gilding method

The most durable and high-quality gilding layer makes it possible to obtain electroplated gold plating, performed in special electrolytic solutions. This technology of gilding is very similar to zinc plating, since it uses electroplating and similar electrochemical processes.

Depending on the chemical composition of the solution in which the galvanization is performed, the resulting gilding may have a reddish or light yellow tint. Basically, gilding of metal products using this technology is carried out in solutions of two types.

Electrolytes for gilding of the first type are prepared in the following sequence.

1. 60 grams of sodium phosphate are dissolved in 700 milliliters of water.
2. In 150 milliliters of water, 2.5 grams of gold chloride is diluted.
3. In another 150 milliliters of water, 1 gram of potassium cyanide and 10 grams of sodium disulphide are dissolved.
4. First, the first two solutions are carefully mixed, and then the third is added to the resulting mixture.

To gild silver or any other metal by this method, the prepared composition is brought to a temperature of 50–62 ° and a platinum anode is used to carry out the process. After the depletion of such an electrolyte for gilding, chloride gold is added to it.

Defects when using gilding electrolytes and ways to eliminate them

It does not belong to noble metals, but has long been used for the manufacture of banknotes and decorative elements. People drew attention to the ability of the material to change its color under the influence of time, taking on various shades (from green to black). The oxidation process, accompanied by a darkening of the surface, can be accelerated - this is the blackening of copper. There are several ways to artificially induce a patina (plaque) on the surface of a non-ferrous metal, giving it the appearance of patriarchy and antiquity.

Purpose of patination

The main purpose of using darkened copper is to give the effect of aging to the metal being processed. In ancient times, most items (coins, figurines, various souvenirs, household items) were made from this material. Having reached our time, objects have undergone some transformations - oxidative processes have changed the color and general appearance of these things, creating all the signs of antiquity and, therefore, value.

In our time, copper patination is done artificially, but at the same time they pursue a single goal - to give things a rare look, to attract attention, to arouse a desire to purchase it.

Preparing for patination

As with any work with chemicals, safety must be the first priority. Most of the compounds used in blackening are very toxic. Emitted vapors can be hazardous to health if released into the atmosphere. There are certain standard rules that should not be neglected:

• it is necessary to store substances in special test tubes, tightly closed with stoppers for sealing;
• keep solutions out of the reach of children;
• the process must take place in a specialized cabinet with built-in ventilation (the cabinet doors should be slightly open).

Before processing, the material should be thoroughly washed, cleaned and degreased to achieve the best effect.

Oxidation and patination- these concepts are not synonymous, the consequences of each of these processes differ from each other in order.

Copper oxidation- the formation of oxides and oxides on the surface of the metal due to its interaction with oxygen-containing elements and other certain chemical reagents.

Patination- formation of a thin layer of chlorine and sulfur compounds by exposing the metal to the appropriate compositions. Both processes lead to a change in the color of the material, for which, under natural conditions, considerable periods of time would be required.

Patination at home

There are several most common and universal methods for blackening copper. The use of these methods allows using chemistry to achieve the desired result in the shortest possible time. The most popular among them are:

• use of boiled eggs;
• exposure to potassium sulfide or sulfate;
• applying a solution of copper sulfide;
• placement in a solution of copper sulphate with zinc chloride or potassium permanganate.

Obvious visual differences between material exposed to time and nature, or treated with a special solution, are negligible, and in some cases not at all. Therefore, artificial patination is a fairly effective technique.

boiled eggs

The easiest way that does not require special chemicals. All actions to achieve the expected result must be performed exactly, following the instructions:

1. boil eggs (at a high temperature, chemical processes take place in the yolk, accompanied by excretion);
2. after 10 minutes of cooking, remove and cool;
3. after cooling, peel and crush into small pieces;
4. place the eggs with the prepared object in a container, cover with a lid (copper should not come into contact with the eggs, but simply lie nearby);
5. leave the ingredients in the container for 30 minutes or more (the longer the metal is inside, the darker it will become).

As a result, from the interaction of copper with sulfur emitted by a boiled egg, the product should change color, taking on a dark brown hue. The number of eggs used in the experiment depends on the dimensions of the copper object (the larger the object, the more eggs). The method of blackening copper with a boiled egg has two significant drawbacks: fragility and instability. Over time, the result will disappear. The advantage is the simplicity and accessibility of the experiment itself.

potassium sulfide

One of the best ways to darken metal is to use potassium sulfide. Before starting the experiment, the product should be thoroughly washed and degreased so that the patination of copper takes place correctly and gives a good result.

The necessary reagent for the reaction is sold in three aggregate forms: solid, gel-like and liquid. Each type is characterized by a different shelf life: liquid - up to two weeks, solid - several years.

For work, you will again need a container in which sulfide will be diluted. The reagent has a high level of toxicity, so precautions should be taken - be sure to wear gloves and goggles. The procedure itself is recommended to be carried out on the street or in a room with a good ventilation system.

The chemical element is diluted only with water (hot or cold), based on the state of aggregation. Dilution of the solution is carried out according to the instructions attached to the purchase. The solid reagent should first be ground into a powder, and then mixed with water until dissolved.

After completing all the preparations, you can place the copper object in the solution and observe the process of the chemical reaction. First you need to prepare the composition of water with soda (1:16) to stop the action of an aggressive substance. At the end of the process, carefully remove the product from the solution with tongs and place it in prepared water with soda to stop the reaction. The copper patination process is over.

Potassium sulfate is produced during the oxidation of the sulfide at high temperature. Its effect on the copper product is faster. The effect produced is similar.

Use of copper sulfide

This chemical is obtained by the reaction of bivalent copper salts with sulfur. The resulting copper sulfide compound is capable of causing discoloration of copper. Moreover, the quality of the shade depends on the saturation of the sulfur solution.

The black substance used is insoluble in water and dilute acid formulations, so the darkening produced is durable and resistant to abrasion or washout.

The termination of the blackening process, as in the previous method, occurs after the product is placed in water with soda dissolved in it. If the resulting color is too dark, it can be lightened by rubbing with scouring powder. Then the copper object is washed with water and dried.

Patination with copper sulphate solution

It is possible to achieve the appearance of a brown film with a red tint on the product. The preparation of the solution is prepared as follows:

• water is poured into a glass container;
• copper sulfate powder is diluted in it;
• zinc chloride is added and everything is mixed.

The ratio of ingredients: 50% - water, 25% - copper sulfate, 25% - zinc chloride.

Depending on the time the object is in the resulting compound, its color can change from red to brown.

The formation of white-green plaque on copper occurs by immersing the metal in the composition obtained by adding potassium permanganate (5 g per 1 liter) to a five percent aqueous solution of copper sulphate.

Artificial copper color

In addition to the methods described, there are other methods for patinating and oxidizing copper, which make it possible to give the material the following colors and shades:

• brown-gray - when immersed in a solution of sulfuric liver;
• dark gray - when the product is heated in a combination of a solution of sulfuric liver and ammonia;
• brown-black - occurs under the action of platinum chloride (if the result is not satisfactory, hydrochloric acid can be added);
• black - as a result of exposure to ammonium sulphur, diluted in water;
• green - from the application of low concentration copper nitrate mixed with common salt, or from oleic acid;
• golden - from being placed in a heated solution of copper sulfide, caustic soda and milk sugar.

The use of each method gives its own result and differs not only in the color of the patina, but also in the duration of the coating. Sometimes, to protect the product, varnish is applied, then the blackening does not disappear at all from time to time.

Nickel plating of iron or steel products is carried out in a solution containing 5 g of nickel sulfate and 4 g of ammonium chloride in 100 ml of water, where several pieces of metallic zinc are additionally added. As a result of the release of nickel, a beautiful silvery film forms on the surface of the product.
*** To cover a copper or brass product with a nickel film, prepare a solution of 10 g of nickel sulfate and 25 g of ammonium chloride in 100 ml of water. This solution is brought to a boil, some iron filings are thrown into it, and then the product that is going to be nickel-plated is lowered.
*** Isolation of metallic nickel on the metal surface occurs as a result of the reduction of nickel sulfate with zinc or iron. The addition of ammonium chloride, which undergoes hydrolysis in an aqueous solution, creates a slightly acidic environment.
*** A high-quality nickel coating on an iron surface is obtained as follows: 3 g of nickel chloride and 1 g of sodium acetate are dissolved in 100 ml of water heated to 60 o C, then the solution is heated to 80 (C) and 1.5 g of sodium hypophosphite is added Then the defatted product is immersed in this solution and heated to 90 o C. If the temperature is lower, nickel plating will go too slowly, and at 95 o C the solution begins to decompose.
In this case, the reason for the release of metallic nickel is the reduction of nickel chloride with sodium hypophosphite in an alkaline environment, which is created during the hydrolysis of sodium acetate. When heated above 95 o C, sodium hypophosphite decomposes with the release of hydrogen, turning first into sodium phosphite Na 2 PHO 3 and then into orthophosphate Na 3 PO 4 .

copper plating. Copper coating of iron products can be carried out in a solution of 1-5 g of copper sulfate and 1-5 ml of concentrated sulfuric acid in 100 ml of water; the process takes only 3-5 seconds at room temperature. The treated thing is removed from the solution, washed with water and dried. When copper plating in this way, the copper salt is reduced with iron.
*** A denser copper film is formed if the product is first treated with a brush with a solution of 10 g of zinc chloride and 20 ml of concentrated hydrochloric acid in 20 ml of water, and then a solution of copper ammonia reagent is applied with a brush. A copper ammonia reagent is prepared by dissolving 5 g of copper sulfate in 80 ml of water and adding ammonia until a clear dark blue solution is formed. Copper-ammonia reagent is a solution of an ammonia complex of copper of composition SO 4 . The separation of a thin copper film is associated with the interaction of the surface layer of iron with the copper-ammonia complex, and pretreatment with a mixture of HCl and ZnCl 2 makes iron more chemically active.
*** For lead copper plating, a solution of 16 g of copper acetate and 15 ml of glacial acetic acid in 80 ml of water is used.

Chrome plating. Coating of steel, copper and brass products with a thin layer of chromium is carried out in a solution containing in 200 ml of water 3 g of chromium fluoride, 1.5 g of sodium hypophosphite, 1.5 g of sodium citrate, 2 ml of glacial acetic acid and 2 ml of 20% - th sodium hydroxide solution. In order for the chromium film on the surface of the product to be sufficiently thick, strong and even, the process is carried out at 80 o C for 3-8 hours, and then the product is washed with water and dried. Before chromium plating, steel objects are additionally coated with a copper film to ensure better adhesion of the applied chromium film to the surface. Chrome plating of metals by the method described here is based on chemical reactions in which sodium hypophosphite and sodium citrate serve as metal reducing agents.

Tinning.(plating with a layer of tin) iron or steel products are carried out at room temperature in a solution containing 2 g of tin chloride SnCl 2 and 10 g of sodium lactate in 100 ml of water.
*** For tinning copper, bronze or brass products, prepare a solution of 1 g of tin chloride and 30 g of ammonium alum in 100 ml of water.
*** Zinc objects are covered with a layer of tin in a solution that contains 20 g of tin chloride and 40 g of potassium hydrotartrate (tartar) in 100 ml of water. A film of tin on zinc forms as a gray coating after just a few seconds. The product is removed from the solution and wiped with a cloth until it shines.

Silvering any fat-free metals are carried out in a boiling solution containing 12 g of yellow blood salt, 8 g of potash and 0.75 g of silver chloride in 100 ml of water. When heated, the sparingly soluble silver chloride is converted into a complex compound of composition K, which is then reduced on the iron surface to metallic silver. At the same time, potassium carbonate removes excess iron salts from the solution, which prevents the formation of a strong silver film, and precipitates a brown precipitate of iron hydroxide.
*** You can also silver metal products with a liquid paste consisting of 10 g of silver chloride, 60 g of table salt, 60 g of cream of tartar and 50 ml of water. Grind in a mortar a mixture of the specified composition, and then, immersing the product in the resulting slurry, heat it for 15--20 minutes. The silver coating obtained by this method is beautiful, but lacks luster. To make it shine like a mirror, the paste is washed off the product, immersed in a solution of 6 g of sodium hyposulfite and 2 g of lead acetate in 100 ml of water and heated to 70-80 o C for 1-15 minutes.
*** Photo paper can also be used for silvering. It is cut into pieces and dipped in a solution of sodium hyposulfite. A fat-free product is also placed in this solution and, wearing rubber gloves, rub its surface with an emulsion layer of photographic paper until a sufficiently dense layer of silver is formed. After washing, the product can only be wiped with a dry cloth.

Turning brass into "gold". If a brass product, after cleaning and degreasing, is immersed in an aqueous solution of copper acetate heated to 30--40 o C, then, depending on the duration of processing, it will take on a new color - from light yellow to ruby ​​red and even purple. Then the product is washed with water and dried. The concentration of copper acetate is selected empirically.
Brass is an alloy of copper and zinc. The appearance of color during the chemical treatment of its surface is due to the reaction of zinc reduction of the dissolved copper salt. Copper, standing out on the surface of brass, gives it different (depending on the thickness of the layer) shades of red. To make the copper coating more durable, it is coated with a colorless varnish.

Turn tin into "bronze" you can, if you immerse it in a solution of 5 g of copper sulfate and 5 g of iron sulfate in 100 ml of water. You can simply wipe the surface of the product with a swab moistened with the same solution. After processing, the product is washed with water, dried, wiped with a cloth and immersed in a solution of 25 g of copper acetate in 100 ml of 10% acetic acid.

bluing- This is the coloring of iron or steel objects in blue-black.
*** This process is carried out by immersing steel or iron objects in a solution heated almost to boiling, containing 7 g of sodium hyposulfite and 2 g of lead acetate in 100 ml of water, and keep it there until the surface of the metal turns black and blue. . When bluing, a thin film of lead sulfide is formed on the product, firmly bonded to the metal.
*** The dark blue color of an iron or steel product is given by keeping in a mixture of equal volumes of 0.5% solutions of red blood salt and iron (II) chloride. The mixture is prepared immediately before metal processing, since the reaction of the formation of a blue complex compound - turnbull blue (iron-potassium hexacyanoferrate) immediately occurs.
*** Brass can also be painted in the color of the "crow's wing" if the brass part is lowered for 1-3 minutes into a solution of the copper ammonia complex, obtained by dissolving 12 g of the basic salt of the Cu 2 CO 3 (OH) 2 composition in 100 ml of 25% th ammonia solution and add 0.1 g of brass filings.

Brass will turn brown, if processed:
*** heated to 70 o With an aqueous solution of 10 g of sodium sulfide in 100 ml of water;
*** heated to 70 o With an aqueous solution of 5 g of sodium hyposulfite and 5 g of copper sulfate in 100 ml of water;
*** heated to 80--90 o With a mixture of equal volumes of 6% lead acetate solution and 18% sodium hyposulfite solution.

For "coloring" copper products in various colors We recommend using the following recipes:
*** 4 g of sodium hydroxide and 4 g of lactose (milk sugar) are dissolved in 100 ml of water, the solution is boiled for several minutes, and then 4 ml of a concentrated solution of copper sulphate is added in small portions with continuous stirring. The defatted product is immersed in a hot solution, and depending on the duration of treatment, its surface acquires a color from golden to green, brown or even black.
As a result of the redox chemical reaction of copper sulfate with lactose in an alkaline medium, gluconic acid is obtained and a precipitate of copper (I) oxide is released. First, a thin yellow Cu 2 O film is formed, which gives the copper surface a golden hue. With prolonged heating, the Cu 2 O crystals become coarser and turn dark red, hence the change in the color of the coating.
*** prepare a solution of 2 g of nickel sulfate, 4 g of Bertolet salt, 18 g of copper sulfate and 0.2 g of potassium permanganate in 100 ml of water. Processing copper products with a warm solution of this composition gives them a "bronze" look;
*** Dissolve 12.5 g of ammonium carbonate in 100 ml of water and add 4 ml of ammonia. The resulting solution is applied with a brush to the surface of the product and a greenish surface is obtained. Under the action of ammonia on the copper surface in the presence of atmospheric oxygen, a complex salt is formed, which then interacts with ammonium carbonate, releasing a green precipitate of copper hydroxide carbonate Сu 2 CO 3 (OH) 2 on the metal surface.

Aluminum "pearl". Clean the aluminum surface with a metal brush, applying strokes in different directions. Chips and dirt are removed with a clean rag and on the prepared surface heated to 80 o C, a 10% solution of sodium hydroxide heated to 90 o C is applied with a brush in an even layer. After the solution dries, a beautiful film similar to mother-of-pearl forms on the metal surface. For better preservation, it is covered with a colorless varnish.