Surface gilding. About gilding. Story. Methods and types. Types of decorative gilding

This is a special coating that is applied to the surface of other metals in order to give them some of the qualities of a noble metal. Thus, the coating helps to reduce the cost of production and make the item attractive to buyers. Gold does not oxidize, does not react to reagents, does not come into contact with water. In addition, coating helps to improve solder and is used in the manufacture of technology, in particular microcircuits.

What is galvanization?

Electroplating with gold is the application of a thin layer of gold to the surface of a part made of metal or other material. The thickness of the layer is determined by the properties of the product that needs it. The layer may be a few millimeters, or it may be only a few microns.

Product before and after gilding by electroplating

What are the advantages:

Helps to give the product a noble look.
Improves properties and characteristics.
Helps protect against destructive factors.

Gold is electroplated onto the surface using thin sheets of metal. Gold leaf is very thin, and the technology of its application to the surface of products has not changed much over the years.

Oil and glue can be used in the process. Based on the oil, a special mixture is prepared, which helps to fix metal or other material products on the surface. In the process, oil varnish is used, as a result of which the coating has a matte finish; in order to give shine to the product, another coating is additionally applied to it.

If a polymer (adhesive base) was used in the galvanization process, then the product may have a characteristic sheen, but the procedure is carried out under special conditions, since humidity can disrupt the process and affect the result.

Electroplating coating is actively used in the manufacture of jewelry, which is invariably in demand among buyers. Cheaper metal is taken as the basis, and a layer of gold is applied on top. Such jewelry is cheaper and looks like jewelry.

In most cases, such a coating is called gilding, it can be applied both to rings, earrings and necklaces, as well as to watches and glasses.

It is noteworthy that in Russia those products that have a yellow-red tint are in the greatest demand, but in Europe preference is given to lemon color.

What metals are coated?

cupronickel;
nickel;
brass;
copper.

Gilding is applied not only to base metals, but also to silver. In addition to gold, other noble metals of the platinum group can also be used.

Jewelry made in this way helps to avoid allergies, it is difficult to attribute them to cheap jewelry, sometimes such jewelry is on a par with products made of silver.

The coating can be applied selectively, mainly this is done so that a separate part of a product acquires some.

Electroplating is used everywhere, since a coating can be applied to any material, thereby decorating it or giving it certain properties. For example, domes of churches are decorated with gold leaf, used as a decorative element or applied to the surface of porcelain.

How is the procedure?

There are only two ways to apply gilding to the material:

Mechanical.
Electrochemical, using current and reagents.

The mechanical method is the application of gold leaf to the surface of the material using glue and oil.

The precious metal is applied to the surface of the product in a galvanic way, while the master covers the surface of the product with gold in the process of work, using an electric current.

The coating, which is applied using current, has several advantages:

increases the wear resistance of the material;
enhances reflectivity;
protects against corrosion;
conducts current.

When applying a layer, the master himself controls the thickness of the precious metal. For a long time, experts agreed that electroplating has only one drawback - it is limited. It was possible to apply the precious metal only to the metal, since it conducts current well. Today we managed to solve the problem, special varnishes and substances that conduct current were created. Their application to the surface of products helps to cover with gilding those materials that are not related to metal.

Diagram of a galvanic installation

The application of gilding to the surface of products is carried out in three stages:

Training.
Application of metal.
Final processing.

The first step can be called grinding. It is carried out using paste, sandpaper; if the surface is well processed, has been prepared, then we can assume that half of the work is finished. It also removes oxides, signs of rust and contamination. The surface is degreased; gasoline and acetone can be used as a suitable agent.

Then the part is immersed in gold, using galvanic baths for this. For the procedure, special devices are needed, which are called drums, they provide current conduction. The bath itself has a special coating that allows it not to collapse under the influence of electric current.

The whole process takes place under the influence of high temperatures and maintaining the current level, therefore, special equipment will be required for galvanization. You can't do this at home. Chemicals are also used in the process.

Processing ends when the surface of the part is covered with a thin layer of metal. Sometimes putting gold on a part is used to increase its volume, and not just improve its characteristics. Not only gold and base metals, but also chromium, nickel, copper can be applied to the part.

Most often, a ligature is applied to the details, and not pure gold. The metal is diluted with other elements, thereby giving the products other qualities and a shade that can attract buyers.

Types of coatings that exist:

Nickel plating is the application of nickel to parts as a coating. Most often, this type of electroplating is used in relation to copper, zinc, aluminum. Nickel protects products from corrosion, while the element is applied not only to metal, but also to wood, porcelain and other materials.
Copper plating - a thin layer of copper is applied to steel in order to give the product certain characteristics. Copper is applied to steel wire or wires.
Silver plating is the process of applying a thin layer of silver to products. This helps protect parts from the effects of the external environment, increase electrical conductivity. In addition, silver can be applied to interior details in order to give them a decorative color and shine.
Rhodium plating is the application of rhodium, one of the most expensive elements, to jewelry or parts. Rhodium has unique properties and protects jewelry or parts from chemicals, water, air and dirt.

electroplating gilding

Silver, copper, nickel, rhodium and other elements can give the part the necessary properties, as well as protect the material from oxidation, corrosion.

The only disadvantage of galvanization is that the coating becomes thinner over time. The layer is erased under the influence of adverse factors. In this case, the surface is exposed, the quality of the material decreases, its appearance deteriorates. If we are talking about jewelry or a small detail, then you can give the item for restoration. The old layer will be cleaned off and a new one will be applied to the objects. But for the work you have to pay a decent amount; the procedure is difficult to attribute to cheap, the cost will depend on the type of coating and the thickness of the layer.

With the development of architecture and art, craftsmen used gold as a special kind of decoration. The effect of decoration was achieved by imposing on the surface of objects made of wood, metal, gypsum, stone, leather, the thinnest layer of precious metal - gold leaf.

Story

Over time, the methods of gilding improved, and the method of decorating with gold leaf was used more and more widely, reaching its heyday in the 18th century.

One of the earliest written records of the use of gold leaf is the 8th century Lucca manuscript. This collection of recipes describes in detail the recipe for the preparation of polyment - the basis for gilding. This material was prepared from “thin” gypsum and an Armenian bolus with the addition of a small amount of honey for parchment and the application of gold leaves on it. Armenian bolus, a natural earthen pigment with a significant admixture of clay and limestone, has been widely known since the Middle Ages, when it began to be used to make polyment.

Similar teachings can be found in many treatises and manuscripts. The most detailed set of rules contains a treatise by Cennino Cennini. The Renaissance painting technician devotes several chapters to the process of gilding with gold leaf on a hard base - a gilding primer composed of an Armenian bolus washed with whipped protein, diluted with water. This composition was applied with a brush on gypsum soil up to three or four times with short breaks. The master also talks about the gilding itself, recommending that the bolus preparation smoothed, and better polished with a tooth, be covered with egg white knocked down with water, and then put leaves of gold leaf on it.

Gilding has been an integral part of Slavic icon painting throughout its centuries-old existence. Starting from the first icons, the craftsmen used all the basic techniques of gilding. “If you are going to gild or silver,” says one of the later copies of the icon-painting original, “put plastic on the board, i.e. leaves of gold or silver, and pour liquid glue. And no board all the way. And dry. And after drying, smooth over with a bone and a tooth with a certain exact same. Mix the same egg white with water and anoint with a brush ”[Code, hands. 112(2)].

Gilding technique

With the passage of time, the technique of gilding improved. Considering all the canons of gilding, the gilding technique is divided into two main methods: polyment gilding and mordan gilding.

Gilding on polyment

Apparently, gilding on polyment was the most common method of gilding, since its recipes, starting from the 17th century, have come down to our time in large numbers. This method of gilding surfaces is extremely time-consuming at all stages of gilding. It is used only by highly qualified craftsmen. Polyment gilding is used in the decoration and restoration of furniture, paintings, other interior items, as well as complex moldings. This method is widespread in icon painting.

Polyment or, as it is also called, glue gilding is carried out on wood, plaster, mastic, papier-mâché. The gilding process consists of the following steps. The surface for gilding is prepared as much as possible: bumps and all sorts of defects are removed, and dust is also removed. Then, using special brushes, the surface is treated several times with wood glue. Only in the case of high-quality gluing, gesso will hold firmly on it. Levkachenie - the next operation, which is carried out with brushes of different formats on a glued object. Levkas is first applied “vnatych” - with quick vertical blows, and then “smoothly” - with even movements. The levka operation is repeated several times, drying each layer. Next, the object is polished with pumice and horsetail, and then, in several operations, covered with polyment using a soft squirrel brush.

The gilding process is carried out in this way: the gold sheets from the book are transferred to a golden knife, and then to a golden pillow, where they are cut into the necessary parts. Then, with a squirrel brush, the surface is treated with vodka, and after that, gold is laid out with the help of a paw. The gilding process is completed by polishing, which is carried out with an agate tooth.

Gilding on polyment gives the greatest artistic effect: the gilded surface has the brilliance of real cast gold with a glossy effect.

Gilding on Mordan

Mordan gilding or oil gilding is called so because in the process of all preparatory operations materials on vegetable oils are used, and the gold layer itself is superimposed on a special mordan lacquer, also made on an oil basis. This method of gilding is simpler and more affordable than gilding on polyment. In addition, muzzle gilding has a significant advantage: the surface gilded by this method is more resistant to moisture and other atmospheric phenomena. Oil gilding is carried out on metal, wood, plaster, mastic, stone.

Gilding on Mordan also consists of a preparatory stage and the direct application of the gold layer. The cleaned surface is primed with red lead paint - a material prepared on natural drying oil. Thanks to this coating, the surface acquires good anti-corrosion protection. Then they begin to putty in several operations, allowing each layer to dry. After that, the surface is polished. A well-polished object is covered with oil varnish. On a primed and sanded surface, some craftsmen put a thin layer of oil or alcohol varnish and, after this varnish pad has completely dried, they apply mordan varnish. After proceed to the gilding of the surface. There are two ways to apply gold: 1) for large planes, gold is applied directly “from the book” and 2) first it is “blown” onto a special pillow, and then cut into separate parts with a gold knife. Then, with the help of a squirrel tail foot, they are transferred to the surface intended for gilding. The second method is used for gilding small details and surfaces with complex relief.

Today, mordan gilding is the most widely used method. It is used both in interior and exterior works. Gilding in a muzzle way gives the surface the effect of velvety and dullness.

Types of gilding

Combined

This is a special type of gilding, when gold is given a delicate matte shade. All preparatory work is of the same type with gilding on polyment. Surfaces with a polished shiny texture are obtained as a result of gilding on polyment, followed by processing with teeth. Matte places are obtained as a result of gilding “to the touch” or on gelatin without polymer coating and without polishing. Surfaces for matte gilding after gesso are not polymerized, but are covered with a layer of gelatinous adhesive solution, and after the adhesive film dries, they are gilded in vodka in the same way as polymerized places. A combination of polyment gilding with Mordan gilding is possible.

Gilding with crafted gold

Gilding with crafted gold is often found on small antique items, especially murals. This method is necessary for the restoration of miniatures of a crushed drawing; it is widely used in icon painting. Gilders perform gold plating with artificial gold on polyment, but the operations are somewhat different from conventional glue gilding. Before polymerization, a solution is prepared on gelatin glue. And on the surface covered with polyment, bronze powder is applied in the color of gold and allowed to dry. Then, using a squirrel brush, cover the surface with a mixture of gum arabic and gold powder. Objects treated in this way acquire a soft, delicate surface, shining with gold.

Water-synthetic gilding

Water gilding is sometimes replaced by a unified polyment, however, in terms of method and effect, this method is more reminiscent of oil gilding. Unipoliment makes it possible to transfer water gilding to architecture. It retains the properties of oil gilding, but at the same time has the brilliance of water gilding. For example, the Kolner Instacoll System was specifically designed as an alternative to oil-based exterior coatings for maximum gloss. Using the materials of this system, you can quickly get the necessary "tack" and, if necessary, restore it with a special activator. The surface after the application of synthetic materials acquires an excellent glossy finish, without requiring additional polishing with teeth.

Bronzing

Bronzing a part means covering the surface with a special metal powder - bronze powder. This solution is often carried out in a muzzle way, as well as with the help of other varnishes. When the necessary “tack” appears during the work, bronze powder is applied with a soft brush, which adheres well to the sticky surface.

Bronzing gives the surface the appearance of real gilding. This coating is anti-corrosion and very stable.

"Garlic" gilding

One of the ancient Russian methods of gilding is called "garlic". Juice is obtained mechanically from fresh garlic cloves. For the convenience of applying gold to it, the juice can be diluted with distilled water. The juice is applied with a soft brush on the prepared surface in an even layer, when it dries, it is polished. The dried and polished layer is moistened with breath until tack appears. Then the gold leaf is transferred to the surface and pressed with a swab. The surface with such gilding acquires an unusual luster.

Gilding "through the fire"

The method of gilding "through fire", or mercury gilding, consists in the fact that the surface is covered with an amalgam of gold and mercury. This method was used for outdoor gilding - gilding of domes, fountains, bridge and balcony grilles.

The cleaned surface is covered with an amalgam, after which the part is passed through a fire to evaporate the mercury. Then the surface is cooled and polished with agate teeth. This method allows the gold to bond firmly to the metal being coated. Usually such gilding lasts more than 100 years.

The gloss of the surface, its durability, as well as the gilding procedure itself and the set of materials depend on the chosen technique for applying gold leaf. However, any method of gilding requires great skill in performing each operation. Skillful details are born after the meticulous work of a master gilder and can last for decades.

Gold is a noble metal with aesthetic appeal and many valuable properties. Since in its pure form it has a high cost, the best solution is to apply a thin layer of gold to the surface of the products. There are different gilding techniques - their choice depends on the size of the object and the goals pursued.

Scopes of gilding

Gilding is used in many areas of our life - it is performed for protective, decorative, protective and decorative purposes. In particular, coating with 18 and 24 carat gold allows you to give a status look to jewelry made of silver or metal alloys, and also helps to restore beauty to gold items that have lost their original attractiveness.

Gilding of decor and household items ennobles the interior of apartments and houses - door handles, forks and spoons, taps, picture frames, metal parts of lamps, etc. are subjected to the procedure.

Increasing interest is caused by gilding moldings, chrome inserts, car grills, handles, key rings. Coating of discs with gold 24 carats, 18Kt/750, 14Kt/585 is practiced.

Plating white, pink, green gold is used in the case of musical instruments, awards, sports accessories. The gilding of engraving, cigarette cases, lighters, flasks, weapon parts, etc. deserves special attention.

The thinnest layer of gold is sprayed onto automobile, window and stained glass to control heat transfer in winter and summer. Gilding is used in dentistry. It is widely used in microelectronics.

The technology involves the following main steps:

choosing a gilding method and preparing everything necessary for its implementation;
degreasing and etching of the surface;
coating;
finishing processing.

In addition to pure precious metal sputtering (24 carats, 999 fineness), yellow, white, pink, red and green gold plating is practiced. Cobalt, rhodium, copper, silver (nickel) respectively act as alloying additives. Instead of 24-carat metal, 18, 14, 12, 10, 9, 8 carat gold is coated - the figure means weight units of pure gold in 24 parts of the alloy.

The technology of coating objects with gold leaf

Gold coating of plastic, wood, metal and other materials is carried out using the thinnest sheets - the thickness of gold leaf (facing) is 0.13-0.67 microns. In the old days, gold leaf was made by hand, today special equipment is used. Depending on the thickness of the sheet, free and transfer (on silk paper) gold leaf are distinguished. It is very difficult to work with the first one - the slightest breath interferes with the process. The finished material is stored in booklets - each of the 60 sheets is shifted with paper. Applying gold leaf is a painstaking process. The technology is based on the ability of rolled gold from a sheet to be attracted to the surface at the molecular level. There are two techniques for gilding with gold leaf: glue (for polyment) and oil (for mordan lacquer). In the first case, a glossy surface is obtained, and in the second, a matte surface. The adhesive method is used when carrying out interior work.

Amalgam gilding

Amalgam (fire) gilding is another ancient method of applying precious metal. It is characterized by a high degree of durability, but the process itself is extremely toxic and is not used today. The essence of the method is the molecular penetration into the base of the precious metal dissolved in mercury (during the firing process, mercury evaporates, and gold remains). An example of such work is the dome of St. Isaac's Cathedral in St. Petersburg.

electroplating gilding

The process of gilding by electroplating is the most commonly used today. It is applicable if the processing of conductive products is carried out. The electrolyte becomes a solution of gold salts. A part is immersed in it - when the current passes, positively charged particles released from metal salts settle on the surface of the product and form an even layer of gold.

An even better result can be obtained using a selective method of electrochemical gilding. The use of this technique makes it possible to increase the rate of metal deposition on the product by dozens of times. The wear resistance and hardness of the gold coating increases by more than 3 times. The penetration of gold occurs at the molecular level. Galvanic methods are used in the gilding of souvenirs, jewelry, dentures, etc.

Immersion gilding technique

This type of gilding does not imply the application of an external current. When a part is immersed in a solution of a less electronegative metal, the process of immersion deposition occurs. After the termination of the contact exchange, it ends. The technology includes several stages - work begins with acid cleaning of the surface and micro-etching, and ends with chemical deposition of a nickel layer and subsequent application of immersion gold. The technology is used in the production of printed circuit boards, element base leads, cases, microcircuits and other products where ultrasonic welding or soldering is required.

Methods of chemical gilding

At home, gilding decor, gold-plating spoons, decorative flowers and other metal objects is carried out by rubbing their surface with chlorine gold paste or immersing in a solution with zinc contact. In the first case, gold is dissolved in a mixture of nitric and hydrochloric acids (1:3). The ratio of gold and solution is 1 g / 10 ml. The liquid is evaporated, observing safety measures. The resulting chlorine gold is combined with melted (elutriated) chalk, tartar and blood salt. After applying the paste with a brush, the object is left for a certain time. Then it is washed and polished. By mixing chlorine gold with ether, patterns and inscriptions are made.

To prepare a solution for gilding from chloride gold, distilled water is combined with it (its temperature should be about 50-60 degrees), potash and salt. An object degreased, acid-etched and washed in water is immersed in a solution and touched with a zinc stick. After the gold precipitation process is completed, the object is washed and polished. To delve into the details of the technology, it is worth watching a master class on gilding.

Pencil gilding

Another "home" method is the use of a galvanic pencil in which the tip is the anode, and the surface of the product is the cathode. The principle of deposition is similar to the electroplating method, but the equipment used excludes the use of a solution bath.

Noble metal not only decorates products, but also performs protective functions. The gilding process should be entrusted to professionals - lack of experience and the use of hazardous components often lead to undesirable consequences.

The oldest technology, with the help of which products from various materials are given a rich, aesthetic look.

Ancient craftsmen used sheet gilding (gold leaf) for gold plating and unsafe technology with amalgam - an alloy of mercury and gold. Today, safe technologies are used in gold plating, for example, with the help of galvanization.

Applications for gold plating

If earlier gold plating was used in jewelry, interior and exterior items, today gilding is used in a variety of areas:

In the chemical industry in the production of paints, plastics and various materials from chemical raw materials.
in various modes of transport. In automobiles, gold plating is used on wires and contacts, microchips and sensors. It is used in such important control systems as ABS, which are responsible for the safety of the car. It is important that the thinnest layer of gold coating gives the parts high corrosion resistance in aggressive environments.
Energy, solar panels. The addition of gold nanoparticles increases their efficiency by several times.
In modern electronic devices, from mobile phones to spacecraft electronics.
In medicine, in diagnostic equipment, in the production of effective drugs used in the treatment of severe infections. Traditionally, gold plating has been used in implants, both in dentistry and in other areas of medicine.

Technologies of modern gilding

Mechanical or sheet gilding

One of the ancient technologies for applying the thinnest sheets of gold to the surface. It is still used in the decoration of interiors, temples, in arts and crafts. Leaf gilding is possible on different surfaces, but more on metals. For example, in the gilding of church domes. But the technology is very expensive, which is associated with a large consumption of gold and is not used on small items. The method has two versions:

Gilding carried out on oil varnish. At the same time, the surface itself can be different in texture: metal, glass, ceramic, plastic, etc. Externally, the gilded surface looks matte, since it is impossible to achieve a golden sheen.
Adhesive gilding. This technology has ancient roots and has not changed much. The method is used only indoors, as the coating is afraid of the influence of atmospheric moisture.

Electrochemical gilding

In the middle of the 19th century, the Russian scientist B.S. Jacobi, performing scientific work on electrochemistry, developed new technologies for applying coatings to metals using electroforming. These developments served as an impetus for obtaining a new method of gilding - electrochemical. This method has two options:

Electrochemical metallization is a modern technology with great efficiency. Coating with gold particles with this method is characterized by strength and fine porosity. A characteristic feature of coatings made by this method is long-term operation with unchanged properties. It is possible to apply the coating on surfaces of different sizes, while the product does not require disassembly. Scope of application from jewelry to elements used in electronics, medicine and other fields of human activity.
Electroplating gilding is currently the most popular gilding technology. A characteristic feature of the method is that the product must necessarily be metallic, or conductive. The essence of the method is that the product, which is in a solution of a metal salt, is exposed to an electric current. As a result of electrolytic dissociation, metal salts decompose into particles with positive and negative charges. Particles with positive charges settle on the metal surface of the item being gilded. Such a coating has good chemical resistance, does not react in aggressive environments. The advantages of the method are the cost-effectiveness of gold consumption, the possibility of coating in hard-to-reach or local places. The method is used on all types of metals and alloys.

Today, gilding services for various items used in various fields are offered by specialized companies with the necessary equipment and consumables. This makes it possible to perform gold plating of products using various technologies and varying degrees of complexity.

In the old days, it was fashionable to decorate interior items of palaces with precious metals, which created the impression of unthinkable luxury and wealth. Nowadays, it is possible to make items sparkling and luxurious with little financial cost. In addition, gilding is a creative process. With it, you can make gilded, gold-plated picture frames from wooden candlesticks, as well as paint boxes and even walls.

It is worth knowing that gilding is a laborious and painstaking process. The naturalness of the type of gilded products depends on the accuracy in the performance of this work. If any cracks, notches or scratches are found on the base, all work will go down the drain. Therefore, before processing the product, it should be well sanded, cracks should be covered, and dust should be carefully wiped off.

You can use the finished gold paint to cover the surface of interior items. However, the imitation of gold will be approximate and will not give the effect that we would like to get.

Even in ancient times, there were two ways of gilding. The first is with the help of a gold leaf sticker (gold foil), and the second is with the fire method using mercury. The second method was very dangerous, since mercury vapor, which stood out during work, were poisonous. Thus, during the gilding of the domes of St. Isaac's Cathedral, 60 people were poisoned by the vapors of this metal. Therefore, this method of coating the surface with gold is not currently used.

Leaf (facing) gilding is widely used in modern technologies. It is divided into free and transfer.

Free gold is so thin that even a simple human breath can easily transfer it from one place to another. Transfer gold has a silky base. After gilding with such material, silky paper is removed from it. Therefore, it is much easier to work with transfer gold.

Leaf gilding can be oil (matte) and glue (glossy).

Oil gilding is the most common and is used to process almost any surface - plaster, metal, wood, plastic. Oil varnish (mordan) is used to cover objects with an oil method.

Adhesive (water) gilding is used only for interior work. The technique of water gilding allows only wood and, in rare cases, polyurethane to be gilded with gold.

Since a real gilded product is quite expensive, they found a worthy replacement for it - potal. Potal is a very thin sheet of an alloy of copper and zinc or copper and aluminum that does not contain precious metals. Therefore, the decoration technique with the help of gilding is much cheaper than with the use of real gold leaf.

With a big stretch, the technique of gluing a gold rolled self-adhesive film can be attributed to potal gilding. With this material it will not be difficult to paste over wooden baguettes or other decorative items that have a flat, smooth surface.

At the end of gilding, both gold leaf and its imitators are usually covered with a protective varnish.