Application of gold plating. Algorithm and rules for gold galvanization. Applications for gold plating

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.

The workpiece is pre-calcined.
The surface of the object is etched first with a solution of sulfuric acid, and then with nitric acid.
The pickled product is momentarily immersed in a mixture of sulfuric, nitric and hydrochloric acids.
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.
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 solution in which galvanization is performed, the formed 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.

60 grams of sodium phosphate are dissolved in 700 milliliters of water.
In 150 milliliters of water, 2.5 grams of gold chloride is diluted.
In another 150 milliliters of water, 1 gram of potassium cyanide and 10 grams of sodium disulphide are dissolved.
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

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 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 are used on vegetable oils, and the golden 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 preparatory phase and directly applying 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.

Gilding is the process of applying a thin layer of gold or its imitation to an object. There are two types of gilding - gold leaf and potal.

GOLD LEAF AND POTAL - WHAT IS THE DIFFERENCE?

GOLD LEAF

Gold leaf- natural gold in the form of the thinnest sheets, which are stacked in books. Classic 960 gold leaf, but there are also other varieties. 960 sheets have a warm yellow native gold, it was these gold sheets that began to be used back in Ancient Rus'. The rules for the production of 960 gold leaf are enshrined in GOST 6902-75.

Gold leaf is suitable for use on almost any surface (wood, glass, ceramics, marble, porcelain, metal, plaster, canvas, paint layer, etc.), and is the only suitable material for gilding large objects such as domes, statues, etc. Gold leaf can be used for gilding objects inside and outside the premises, it does not oxidize and does not darken.

POTAL

Applies to interior work only. Recommended for water-repellent surfaces (glass, metal, plastic, etc.) and vertical surfaces. The adhesive is applied with a flat brush on the prepared surface, reaches technological stickiness after 30 minutes and remains usable for 3 hours.

Diluted with alcohol thinner.
For professionals

These tools are usually used when working with gold leaf.

Professional mordan, it is applied both to internal, and to external works. Suitable for all types of surfaces. The adhesive is applied with a flat brush to the prepared surface. The time after which it reaches technological stickiness depends on its type: slow-drying - 12 hours, quick-drying - 1.5 hours. Slow-drying mordan remains usable for 24 hours, quick-drying - for 1.5 hours.
Diluted with white spirit.
Rabbit (rabbit) glue
For special techniques and restoration work. Glue of animal origin, available in granules for easy storage. It is used to create an adhesive base for sheets of gold leaf or gilding. To prepare the glue, it is necessary to dilute the glue in a water bath (100 g of granular glue per 1 liter of water) and filter it with a fine mesh. You can start gilding a few hours after applying the glue.

Fish glue (gelatin)
Gelatin is usually sold in the form of flakes, which must be soaked in water for about 24 hours before use. After softening, it is necessary to finally dissolve the glue in a water bath. Unlike other adhesives, when diluted with water, it slightly increases in volume. Gelatin is used to stick the gold leaf onto the bolus.

Aging

Makes gold shine darker and duller. It is used to give products an aged look. After drying, after 12-24 hours, the bituminous varnish is fixed with shellac varnish.

Paste bitumen is a dense, viscous substance of dark brown color. It has the same properties as ordinary bitumen. Lays down practically on any surface. Dries out in 12-24 hours. Lacquering is recommended to prevent rubbing.

It is used to give an aged look to decorated objects, and in the technique of gilding. Applies to any kind of base. After drying, it requires fixing with a finishing varnish.

Finish coat

Varnish Mecca- protective lacquer applied to gilded objects to protect against aging and impact environment. Available in two types: colorless and gold. The second varnish is used if you want to darken the tone of gold or give a golden hue to silver.

Varnish Tsapun(lacquer Tzapon) - nitrocellulose transparent varnish for protection of products covered with potal. Dries quickly, forms a transparent protective film on shiny metal surfaces, preventing discoloration and corrosion. Suitable for processing products made of silver, copper, brass, bronze, tin, iron.

Water-based varnishes can oxidize potal, therefore, if the use of such a varnish is required, at least three protective coats of alcohol-based varnish must first be applied.

Shellac (Pure gummilac)
After drying, shellac forms a strong, abrasion-resistant, vitreous film. Interferes with formation of cracks and protects a leaf from mechanical and atmospheric influence. Ideal for gilded pieces of furniture that are in frequent use.

Shellac is available both in the form of flakes, from which you can make your own varnish, and in the form of a ready-to-use varnish.

Tools

Brush for transferring the gold leaf/solid onto the gilder pad or surface. The brushes are made from oxhair or squirrel and range in size from #35 to #85 and larger. Thanks to the use of lampenzel, the thinnest sheets of gold/gold do not crumple or tear during transfer.