Home electroforming. Galvanic baths - what is it, principle of operation, design

Electroplating is a home-based process used to coat one metal with elements of another metal.

Electroplating is transmission electric current through a solution called an electrolyte. This is done by dipping two terminals, called electrodes, into electrolyte and connecting them to a circuit with a battery or other power source. Electrodes and electrolyte are selected elements. When electricity flows through the circuit, the electrolyte begins to split, and some of the metal atoms from its composition are deposited in a thin layer on the surface of one of the electrodes. All types of metals can be processed in this way, including gold, silver, tin, zinc, copper, cadmium, chromium, nickel, platinum and lead.

Italian inventor Luigi V. Brugnatelli invented the art of electroplating in 1805. He connected a wire between a voltaic (battery) and a gold solution.

A wire connected to a metal object would ground the circuit, and as current flowed, the gold would become attached to the surface of the metal object to make a smooth, shiny coating.

Electroplating became an important commercial process in the 1840s when John Wright (England) discovered that gold or silver could be dissolved in potassium cyanide for use in plating. One of the first companies to use the new process was the English firm Elkington & Mason, which opened a silver production facility and made spectacle frames, feathers, and other small metal items that could be plated in large quantities.

For many years, electroplating was used primarily to produce expensive items from inexpensive materials.
In the 19th century, national churches used, for example, thousands of religious icons plated in gold or silver. However, in later years, companies used electroplating to create objects that could not be easily duplicated even when using expensive materials. Classic example is a car bumper.
Process Features
Electroplating, including at home, is very similar to electrolysis (where electricity is used to separate a chemical solution), which is the reverse procedure in which batteries produce electrical currents.
It is necessary to use the correct electrodes and electrolyte solution for electroplating at home, having predetermined chemical reaction or reactions that will take place when an electric current begins to act. The atoms that attach to the product come from the electrolyte. Therefore, if there is an electroplating process for copper plating, you need a copper electrolyte, and for gold plating, you need a gold-based electrolyte.
During electroplating, the master must make sure that the product to be used is completely clean. Otherwise, when atoms from the electrolyte arrive at it, they will not form a good bond, and the elements may simply precipitate. Typically, cleaning is accomplished by immersing the electrode in a strong acid or alkaline solution, or by (short) connecting the plating circuit in reverse. If the electrode is truly clean, the atoms from the metallization combine into a very strong crystalline structure.
Electroplating, done at home, involves passing an electrical current through an electrolyte. This is done by dipping two terminals, called electrodes, into electrolyte and connecting them to a circuit with a battery or other power source. Electrodes and electrolyte are made from carefully selected elements or compounds. As electricity flows through the circuit, the electrolyte is broken down and some of the atoms of the material it contains are deposited in a thin layer on top of one of the electrodes. In this way, home electroplating is realized. All types of metals can be plated in this way, including gold, silver, tin, zinc, copper, cadmium, chromium, nickel, platinum and lead.
To achieve an even electroplating finish, the technician must first clean the surface of your metal object and prepare necessary equipment. Dirt and oils on the surface may prevent the donor element from covering the surface. Start with degreasing, detergent (dish soap), and then scrub the metal with an abrasive acid cleaner to get a very clean surface.
Materials for technology
Necessary equipment if galvanoplasty is performed at home
Metal object to be coated (must be steel).
Power supply (3v-6v).
Zinc sulfate / zinc hydroxide / zinc chloride.
Water.
A glass (instead of a glass or plastic object).
Zinc (can be found inside Zn-C batteries).
Sand paper (120).
DIY galvanic bath or similar container.
Tissue paper.
Wires.
Clean workplace sufficient for electroplating.
Source needed direct current with voltage regulation, home socket is not suitable.

What do you need to prepare electrolyte at home? Different products require different solution compositions. For the solution, water with acids and other important inclusions of salts and metals is used. Do-it-yourself electroplating allows you to process many parts and tools for decoration or to increase wear resistance. The temperature of the electrolyte plays a different role in different operations. For example, when chrome plating, the higher the temperature, the brighter the coating is expressed.
Preliminary actions
How to prepare a product made of steel or other material before the process begins at home?
Many of protective coatings include special provisions for surface preparation for electroplating during DIY plating.
Materials that cleaning chemicals cannot remove
There are some materials that chemicals cannot be removed or does so with great difficulty for the galvanizing process. Here is a list of the most common of these materials:
weld slag and other welding flux residues;
splashing and splashing;
burrs (may include excessively rough edges from flame cutting);
mill coatings such as varnishes or varnishes found on some types of pipes;
epoxy, vinyl and asphalt;
sand and other impurities for castings;
oil paints and markers;
pencil markers;
very heavy or thick deposits of wax or fat.

These materials must be removed from the surface before it is delivered to the galvanizing plant or in the case of domestic conditions.
There are various generally accepted standards for abrasive blasting, hand cleaning and power tool cleaning that are effective in removing these materials. Abrasive blasting is usually necessary for castings to remove sand and other impurities from the casting process. Alternatively, a variety of products can be used that are compatible with the electroplating process to reduce the need for blasting or power tool cleaning. The use of uncoated electrodes avoids the problem of flux deposition during welding, which is harmful during the operation. Markers are available that easily dissolve in the baths used in the galvanizing process.
Electroplating at home with muric acid
To set up a home plating system, you will need water, muriatic acid, a 6-volt flashlight battery, a pair of wire clamps, a piece of copper, a piece of metal to process, and a container to hold the components that are used during liquid plating. The 6-volt battery has two terminals for easy connection to the system. It is acceptable to use a less powerful power source.
Crocodiles fix a piece of copper (as a source of elemental ions that will be used for plating) and the main workpiece. Steel and nickel are two elements that can easily be plated with copper.
After cleaning the surface of the material with various detergents it is necessary to create a galvanic solution.
5 parts water are mixed with 1 part hydrochloric acid. Do not add water directly to the acid! Such actions cause a violent reaction with possible explosions.
Always maintain a 5:1 ratio. For example, if you need more than 5 cups, measure 10 cups of water and add 2 cups of acid. For mixing use plastic tools, since acid destroys metal. The top of the container will begin to heat up as the acid reacts with the water.
Connect the alligator clip to the power source terminals. The battery will supply the current needed for the plating process. Attach one clip to one alligator clip and the other to the second terminal of the battery.
Connect the copper to the positive terminal of the battery. Using an alligator attached to the positive terminal of the source, secure the other end with a metal piece of copper. In another scenario, galvanizing will not be able to work.
Connect to the circuit the part that will be connected to the negative terminal of the battery. If possible, attach the clip in a place where galvanization is not necessary. If there is no clip to attach free space, you will need to change the position of the crocodile during the process so that the product does not show marks from the use of clips and the coating is uniform over the entire area.
If the process doesn't work, make sure you have the correct terminals installed.
Immerse both elements in the prepared bath of dilute hydrochloric acid. The copper piece does not have to be completely immersed in the solution, but the product that is being processed is completely immersed in the working environment.
To ensure an even layer, it is recommended to periodically stir the solution in the container.
The two pieces need to be kept away from each other to avoid spots where copper accumulates too quickly.
Using this method makes it difficult to get a thick layer of copper, but you can get a thin coating. When you are satisfied appearance material, the object is pulled out and dried.

Coating can take from a few minutes to several hours. After the desired layer has been formed, the material must be dried.
Electroplating with a metal ionic electrolyte solution at home
To electroplate at home with this method, you will need a piece of copper, the metal to be plated, vinegar, hydrogen peroxide, clamps, a 6-volt flashlight battery, a plastic container.
Use a container large enough to submerge the material you are trying to pour.
Mix and heat equal parts vinegar and hydrogen peroxide. To make four cups of solution, add two cups of vinegar to two cups of hydrogen peroxide. The combination of vinegar and hydrogen peroxide makes peracetic acid, which should be handled with care.
The copper pig should be dissolved in the composition. The liquid will turn blue, indicating that the solution contains copper ions, which can be used to plate the material.
Soak the copper until the solution turns blue. It is better that the solution has a weak concentration; the solution should not be too dark.
Attach the clamps to the battery. The battery provides the current needed to transport the metals from the donor to the recipient. Connect one alligator clip to the positive terminal of the battery and the other clip to the negative terminal.
Clean metal at home to be electroplated. Before starting the galvanizing method, you must ensure that the metal is clean so that the new atoms can form a solid bond with the recipient metal.
Connect the positive clamp to the copper part.
Connect the negative alligator to the metal cover. Try to attach the alligator in an inconspicuous place. If you attach metal to the positive pole, electroplating will not work.
Immerse the elements in copper liquid. Once both metals are connected, immerse them in blue copper solution, prepared earlier. Since they are connected to the battery, current flows through the circuit. The procedure continues until a satisfactory level of coverage is achieved.

Features of galvanization with various metals at home
The option of applying a thin layer to a metal object at home can have a decorative function, or provide corrosion resistance to parts, and restore performance characteristics.
Nickel plating is the process of depositing nickel onto a metal part. Decorative bright nickel is used in a wide range of applications. It provides high degree shine, corrosion protection and wear resistance. In the automotive industry, bright nickel can be found on bumpers, rims, exhaust pipes and trim. It is also used for bright work on bicycles and motorcycles.
A chrome layer at home can be decorative, provide corrosion resistance, facilitate cleaning procedures, or increase surface hardness. Sometimes a less expensive chrome simulant may be used for aesthetic purposes. Electroplating chrome plating at home can also be done at home.
Copper plating is practiced to produce a protective layer or increase the electrical conductivity of the material. To create such a layer, poisonous cyanides, which are dangerous to life, are used. This operation is not performed at home. Initially, steel products are nickel-plated and only then coated with copper.
Galvanizing is considered the most in a simple way electroplating of products. The electrolyte consists of zinc sulfate (200 g), ammonium sulfate (50 g), sodium acetate (15 g) per 1 liter of water. In such a solution, the zinc will dissolve and then successfully coat the workpiece.
Brass plating is used in decorative purposes for accessories. For the operation, the electrolyte must contain copper and zinc salts mixed in a cyanide solution. Electroplating with brass at home is also not recommended.
Silvering and gilding have found industrial use as a conductor and decorative layer. The product is pre-plated with nickel and then coated with silver or gold. To carry out the operation, the electrolyte must contain silver chloride, ferric potassium cyanide, and soda ash. Such a liquid should be heated to 20 degrees, where graphite material can be used as an anode.
Electroforming at home can be used to create exact replicas of metal parts, plates or circuits. Also, the use of technology will enhance the working properties of the workpiece. For such purposes, gold, silver, nickel, chromium or similar metals are used.
Precautions when working with hazardous chemicals
Proper protective equipment should be worn when working at home. When electroplating metals, you are dealing with acids and other chemicals that you need to protect yourself from. Safety glasses, gloves and lab coats are required. Clothes that you don’t mind getting damaged during the metal galvanization procedure are welcome.

The main task of electroplating with copper at home, or copper plating in other words, is to prepare the metal surface for further processing. Such an operation may be subject to various metals, and non-metals, among which we should highlight:

steel,
brass,
nickel and others.

Use of copper

Due to its numerous advantages, this metal has received wide use. Today, copper and its numerous alloys are widely used in industry. The metal is relevant for aircraft manufacturing, automotive manufacturing, instrument making and other industries. Metal and products made from it are no less popular in the domestic sphere. Copper plating itself is one of the the best ways covering a thin layer of metal surface. At home, copper plating can be done in several ways.

Galvanic copper plating at home

For this you will need:

Water;
Hydrochloric acid in its pure form.

Galvanic copper plating at home

Preparation of the solution

We make a saturated solution of copper sulfate, after which you will need to add 1/3 of this solution to hydrochloric acid. After preparing the copper sulfate solution, it should be thoroughly stirred so that there are no particles. Next, you need to add hydrochloric acid in a thin stream to this solution. Don't forget about safety precautions and use gloves and safety glasses. After you have added hydrochloric acid to the solution, it should be mixed thoroughly.

So, the solution is ready and you can start copper plating at home. To do this, you need to take the metal part on which you are going to apply a layer of copper and prepare it for work. Preparation includes processing it sandpaper. This procedure not only allows you to clean metal surface, but also degrease it. The same procedure will be relevant for parts made of brass or lead. After this, the coating must be thoroughly washed in a solution of soda ash. This will allow the material to be degreased more thoroughly.

Soda ash for degreasing material

Next, the surface must be immersed in a solution of copper sulfate and hydrochloric acid. Please note that the first layer of copper is very thin and weak, so it is advisable to remove it with a wire brush. After you have done this, the surface of the steel or lead should be washed again in a solution of soda ash and again immersed in the copper plating solution. These manipulations will lead to the fact that the layer of copper on the surface at home will be much thicker and much stronger, since it can be removed from the object only using sandpaper, and not a metal brush as before.

This method allows you to make a very high-quality copper coating that can only be removed with sandpaper. To improve the copper coating at home, the part should be immersed in the solution again. This method is distinguished by its simplicity and high efficiency including for lead products.

Copper plating procedure

Copper plating is usually called the procedure for galvanic deposition of copper; the thickness of the copper layer in such cases can be from 300 microns or more. Copper plating of steel is one of the most important processes in electroplating, since it is used as additional process before applying other metals for chrome plating, nickel plating, silver plating.

The copper layer adheres perfectly to the steel and is able to level various defects on a surface.

Copper coatings are characterized by high adhesion to other surfaces, lead products, especially metal ones, as well as high electrical conductivity and ductility. The newly applied coating has a bright pink matte or shiny color. Under the influence of atmospheric influences, copper coatings can oxidize and become covered with a coating of oxides with various rainbow-colored spots.

Areas of use of copper plating

Generally, electroplating copper plating can be used:

For decorative purposes. Given the enormous popularity of antique copper products these days. There are methods of artificial aging of steel products;
In galvanoplasty. Widely used in the jewelry industry, among souvenir products, for making bas-reliefs, etc.;
In the technical industry. Copper plating of metal is very important in the electrical field. The low cost of copper plating compared to gold or silver coatings makes it possible to reduce the cost of manufacturing electrodes, electrical busbars, contacts and other elements from lead steel.

Copper plating occurs together with the application of other galvanic coatings

If you need to apply a multi-layer protective decorative coating onto a layer of steel. In the vast majority of cases, copper is used here together with nickel and chromium. This allows you to improve adhesion to the base metal and obtain a shiny, high-strength coating;
To avoid cementation of the area. Copper plating of lead will prevent carbonization from occurring on steel areas. To apply the copper layer, use only those areas where cutting will be carried out;
When performing restoration and restoration work. This method Most commonly used for restoring chrome parts on cars and motorcycles. For these purposes, a fairly thick layer of copper is applied, about 100-250 microns or more, which makes it possible to cover all defects and damage to the metal for applying subsequent coatings;

Types of copper plating

Using electrolyte immersion;
Without immersion in electrolyte.

The first method involves processing metal product sandpaper, brush and rinse with water. After which degreasing in a hot soda solution with repeated rinsing. Next, two copper plates – anodes – are lowered into a glass container on copper wires. The part is suspended on a wire between the plates, after which the current is started.

The second method is relevant for products made of steel, aluminum and zinc.

Home copper plating

This procedure is relevant for various cases, since applying a layer of copper can be used for aluminum cutlery, souvenirs, candlesticks, etc. Non-metal products on which a layer of copper has been applied have a unique effect. These can be plant stems, leaves, etc. Due to the fact that the objects being coated do not have a conductive layer, a special electrically conductive varnish is used instead, which is applied to the surface.

The varnish contains a number of organic solvents, foaming agents and finely dispersed graphite powder, which creates electrical conductivity. The varnish is applied in a thin layer to a dry surface, and after drying in an hour, you can begin copper plating. If desired, copper can be given different color shades using special methods. High quality and the uniqueness of such products is quite deservedly equated to real jewelry.

Video: Copper plating at home

To create a uniform coating on the material, a galvanic process is used, which uses electric current. We propose to consider what galvanic baths are, their principle of operation, design, and we will also provide a drawing for creating such a device with your own hands.

What is electroplating?

Electroplating is a process that uses electric current to reduce dissolved metal cations so much that they form a single coating on the metal of the electrode. The term is also applied to characterize electrical oxidations from anions on a solid support, such as in the formation of silver chloride on silver wire, silver chloride electrodes. Electroplating mainly is used for changing the surface properties of an object:

Eliminate physical damage and increase wear resistance;
Increases corrosion protection, reduces slip;
Improved aesthetic qualities;
Galvanic processes are also used to increase thickness on low-growing parts of an object or to form densities.

The process in which it is used galvanic etching, is called electrodeposition. It is the opposite of galvanic action. With its help, you can carry out both electrical cleaning of a part and apply galvanic coating to it. It depends on what the part is connected to (anode or cathode). The vessel of the galvanic bath is filled with an electrolyte containing one or more dissolved metal salts, which increases the passage of electric current and promotes the formation of ions.

Photo – Galvanic installations

Once direct current is applied to the anode, its constituent metal atoms are oxidized and dissolved in the electrolyte. At the cathode, the reverse process is observed - dissolved metal ions begin to precipitate, forming a coating. The rate at which the anode dissolves depends on the surface area of the cathode along which the electric current flows. This is how galvanic four-chamber automated baths work.

The longer the object remains in the bath's electrical environment, the thicker the coating layer will become. For example, after electroplating, the gold-plated metal layer can be as thin as 10 microns for real gold and 20 microns or more for silver-plated devices.

Photo – Galvanic bath drawing

The shape and contour of the object can affect the thickness of the coating. Metal objects that have sharp corners and the ribs tend to have a thicker coating at the corners and a thinner coating in the recesses. This occurs because direct current flows more densely around the outer edge of an object than in the recesses. Items such as watches with sharp faceted corners and rings are difficult to process evenly. Because of this correspondence it is necessary to use different levels current and angles of influence.

Photo – Galvanization

With rare exceptions, galvanic processes will not hide pre-existing surface defects (such as scratches and dents); on the contrary, they may even make them more visible. Therefore, it is necessary to rub or physically treat any surface before applying the coating.

As a result of galvanic action, the internal structure of the material remains unchanged. For deep impact they are used various technologies, for example, chemical techniques, shot blasting, etc.

Application

Generally, electroplating is used for decorative finishing metals in jewelry and the decorative metallurgical industry. The most popular metals for coating: palladium, gold, silver, rhodium, ruthenium.

There are other galvanic processes that use non-consumable anodes such as lead or carbon. These methods use metal ions; after gilding they must be constantly renewed, because... gold is quickly corroded by salts. Most often, such technologies are used for jewelry production, galvanizing of mechanical parts, chrome plating, degreasing and nickel plating.

Photo – Bell galvanic bath

Electroplating at home - step-by-step instructions

Now we propose to consider how to galvanize metals yourself.

What do we need:

glass container;
copper sulfate (copper sulfate is toxic - be careful);
clarifier;
copper electrode (copper sheet or flexible copper disks);
crocodile clips;
power supply with the ability to adjust the output voltage.

Of course, chamber galvanization is not carried out at home, but this procedure can be used to coat jewelry, cutlery, and wash or clean parts with copper.

Select the object to be electroplated. If it is made of natural material, say, wood or shell rock, then it is necessary to cover it with enamel, otherwise the effect will not be achieved, and the object itself will be damaged. At home, you can use nail polish, paint, or sealants.

Preparing the bath for use

It is necessary to pour copper sulfate into a glass container (this substance can corrode plastic containers, although they carry out lining of production baths) to a level so that the galvanization object is completely contained in the tank. Take the copper anode (+), bend it as shown in the photo. Make sure that the electrode does not break. Check how freely the part fits in the bathroom and whether it is in contact with the anode.

Photo – Home bath for galvanization

If you want to use a very low DC voltage, less than one volt, then you need to organize a large area of water. It is advisable to first calculate the coating and the amount of liquid so that the dimensions of the container correspond to the current parameters.

Photo – Anode

Nutrition

The positive output of the power supply (+) is connected to the copper anode, make sure that it protrudes above the surface of the solution. A negative charge (-) is applied to the cathode on which the part is placed. Place the object in the bath, making sure that parts of the object do not touch the copper. After which you can turn on the power supply. Watch for the formation of bubbles; if they appear, the voltage is too high and should be reduced. Also look at the voltmeter readings, most often 1 volt is enough.

Photo – Galvanization scheme

The whole process will take a few minutes, but you need to check the coating regularly; if the copper coating begins to fade, add a little bleach to the solution.

Rinsing

Immediately after removing the object from the galvanic bath, rinse it with water to remove any remaining copper sulfate solution, and then wipe it dry. Treated areas should be shiny and smooth. After work, you can analyze the dosage of vitriol and the level of desired voltage.

Photo - Galvanization with copper sulfate

This pattern is perfect for creating your own jewelry, refreshing old accessories, and making your own engraving. To coat larger parts with copper, you will need to increase the power of the device. With this device, the design and drawings of which are given above, you can copper-plate (coat with copper) almost any small parts to create home souvenirs.

Price overview

Independent production of gold-plated and copper parts is a very expensive task, because galvanic baths are not so easy to buy, and their price is high. We propose to consider how much these devices cost in various cities of Russia, Belarus and Ukraine (the price is taken as the average for countries and individual regions):

Sales are carried out either from manufacturing plants or in specialized stores. Be sure to check the GOST, certificate and passport of the device before purchasing. Sellers often provide a 12-month warranty on bathtubs.

Galvanoplasty - a technique of electrolytic deposition of metals on the surface of various objects (matrices) in order to obtain exact metal copies - was first developed and put into practice in 1838 by the Russian scientist, academician B. S. Jacobi. With his direct participation, many wonderful works of art, statues and bas-reliefs were made for St. Isaac's Cathedral, Hermitage, Winter Palace, Peter and Paul Cathedral, including the famous quadriga for the pediment of the Bolshoi Theater in Moscow.

Electroplating is based on the crystallization of metals from aqueous solutions their salts when a direct electric current is passed through them. This process is called electrolysis.

Current is supplied using two metal plates - electrodes placed in an electrolyte. The plate connected to the positive pole of the current source is called the anode. The other plate connected to the negative pole of the current source is the cathode.

In electroplating, cathodes are objects (matrices) on which metal is deposited, and anodes are plates or rods of metal with which this object (matrix) is coated.

The electrolysis process is shown schematically in Figure 1. When current passes through the electrolyte, the anode attracts negatively charged ions, and the cathode attracts positively charged ions. When the ions reach the electrodes, they lose their charge, releasing as neutral atoms or groups of atoms.

Electroplating is widely used in industry for the manufacture of molds, hollow thin-walled tubes, and complex parts with wall thicknesses from several microns to tens of millimeters. The dimensions of the parts are limited only by the volume of the electrolyte baths.

Matrices are made of plastics, glass, stainless steel, aluminum, various low-melting alloys, and lead. An electrically conductive layer is first applied to the surface of the matrix of insulating material.

Matrices can be destructible or permanent. The former are made from low-melting metals and plastic alloys. The materials for the manufacture of the latter are steel, copper, nickel or aluminum and its alloys.

To make metal tubes at home, you need a glass, ceramic or vinyl plastic bath, copper sulfate, sulfuric acid, a 20 Ohm rheostat (maximum current 1 A), an ammeter with a maximum needle deflection current of 1 A, a power source, wire (copper, steel or from low-melting materials and their alloys, for example, tin-lead) as a matrix.

The diameter of the wire corresponds to the internal diameter of the tube being manufactured, and the length of the first should be twice longer second.

If tubes with an internal diameter of less than 1 mm are needed, use steel wire. When producing tubes with an internal Ø of 5 mm or more, the matrix is made of low-melting metals and their alloys (for example, bar solder).

The wire should be smooth and even. To do this, it is sanded with fine sandpaper and then finished with micro-skin (“zero”). Then the wire is tinned, excess solder is removed by pulling the heated wire through a rag clamped in a fist. Non-working areas of the matrix are covered with plasticine.

IN warm water(50-60° C) dissolve copper sulfate (200-250 g of salt per 1 liter of water) using a glass container. The settled electrolyte is filtered and then sulfuric acid is poured into it at the rate of 50-60 g per 1 liter of solution.

It should be remembered that you cannot pour the solution into concentrated sulfuric acid. When it comes into contact with water, it causes a violent reaction with a large release of heat and vaporization. As a result, acid may escape from the vessel. Therefore, you need to pour the acid into the copper sulfate solution in a thin stream, stirring continuously with a wooden stick.

To ensure that the copper deposit is dense and fine-grained, it is recommended to add a little ethyl alcohol to the electrolyte (5-10 g per 1 liter of electrolyte).

The finished electrolyte is poured into a working bath, where matrices and a copper plate or wire are placed.

The matrices are connected to the “minus”, and the copper plate or wire is connected to the “plus” of the power source. The anode area should be 5-10 times more area cathode

The installation diagram for home electroforming is presented in Figure 2. The power supply transformer has the following data: core Ш20Х20, winding I contains 2200 turns of PEV-1 0.12 wire (at 220 V) or 1300 turns PEV-1 0.15 (at 127 V ), winding II-35 turns PEV-1 0.8.

The electrolysis process and the quality of the coating depend mainly on the composition of the electrolyte, its temperature and current density.

Electrolyte temperature 18-25° C.

Current density - the amount of current per unit surface - is calculated using the formula:

where i is the current in the circuit, A,

S – surface of the product, dm 2.

In practice j=1-1.5 A/dm 2.

Example 1. Determine the value of the working electrolysis current for the manufacture of a tube with an outer diameter of 5 mm and a length of 100 mm. Let's take the current density equal to 1 A/dm 2, then

I=jS=1*3.14*0.05*1 =0.16A.

Calculation of the exposure time of parts under current in a galvanic bath to obtain a layer with a thickness of σ mm is determined by the formula:

t=σ*d*1000/j*C*η,

where t is holding time, hours;

σ - tube thickness, mm;

d- specific gravity copper, g/mm 3;

j - current density, A/mm 2;

C - electrochemical equivalent of copper, g/Ah; η - calculated current output.

Specifically for our case we have

d = 8.95 g/mm 2, i = 1 A/mm 2; C = 1.186 g/Ah; η = 95.

Example 2. Determine the exposure time of the matrix under current in a galvanic bath to obtain copper tube with a wall thickness of 0.5 mm.

t=σ*d*1000/j*C*η=0.5*8.95*1000/1*1.2*95= 40 hours.

After the calculated time has elapsed, the matrix is removed from the galvanic bath and washed with water. The end of the wire is bitten off at a distance of 1.5-2 mm from the tube and after heating to a temperature of 200-250 ° C, the extended tube is easily removed from the matrix.

In the same way, tubes are made from nickel, chromium, and iron.

V. BUSHUEV, A. NOVIKOV, Voronezh

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Electroplating is a branch of electrochemical science that studies the deposition of certain elements onto any surface. Using electroplating at home or in industry, you can apply a thin layer of metal to a product, which will act as a protective layer or perform decorative functions. IN Lately decorative coating is gaining popularity among those who want to make original gift to your friends and family.

General information

Galvanic coating can be technological or decorative and protective. This is a thin metal layer that, depending on the galvanic elements, can perform aesthetic functions. Electroplating does not increase the strength of the product, since in this case large production capacities are required, but for beauty and giving “freshness” it is quite suitable.

Galvanic reactions occur using direct electric current. A solution - an electrolyte - is poured into a special dielectric container, into which two anodes are immersed. Anodes must be made of a metal that will be deposited on the product being coated.

The workpiece is connected to the negative terminal and placed between the anodes. It acts as a cathode. The anodes, in turn, are connected to the positive contact of the power source. They become part of the circuit, conducting current into the electrolyte and giving it their metal elements. The electrolyte transfers the necessary particles of the workpiece, they gradually envelop it with a thin layer. The area of the anodes must be several times greater than the size of the workpiece.

In other words, galvanization is the transfer of solution metal molecules to the product while an electric current flows through them.

Any galvanic process can be broken down into general steps:

Assembly of galvanic installation.
Preparation of electrolyte solution.
Sample processing and preparation.
Start of the galvanic process.

You can prepare the equipment yourself. First, a suitable power source is selected. This can be a battery (for processing small-sized products) or a battery. A step-down power supply is suitable, which produces a direct current output of up to 12 volts. Sometimes an inverter is used welding machine. A rheostat is selected to regulate the current strength.

A wide and deep bath is selected from a neutral material that is resistant to chemically aggressive substances. It must be taken into account that the electrolytic solution during the galvanic process can heat up to ninety degrees Celsius.

Two plates are prepared that will be conductive anodes.

To heat a container with electrolyte you need electrical appliance with the possibility of smooth adjustment temperature regime. Most often they use the soleplate of an iron or a small electric stove. With their help, the solution is heated to the required temperature and the reaction is accelerated.

Chemical reagents must be stored in tightly sealed glass containers. It is advisable to sign each item.

You will need a scale to accurately measure the mass of substances, since the required accuracy of the weight of the components is one gram. You can purchase such scales, or you can make them yourself, using old Soviet coins instead of weights. The weight of the “yellow” coins exactly corresponds to their face value.

After the necessary substances have been collected, containers have been found, an electrical circuit with power has been assembled, and the heating system has been prepared, you can start cleaning the workpiece.

If the part is not cleaned well enough, the galvanic coating will not adhere firmly or be uneven. Sometimes simply degreasing the item is enough. A solution of acetone or alcohol can degrease the surface well; gasoline can be used.

Some craftsmen keep steel products in a sodium phosphate solution heated to 90 degrees Celsius. Non-ferrous metals can be cleaned in the same solution without heating it.

If the product has corrosion or other flaws, then the surface of the workpiece is sanded with sandpaper.

Sometimes about safety precautions when various works at home they tell it in passing. But when performing any galvanic work, safety must be strictly observed.

The danger lies in the use of toxic chemical substances, high temperature heating the solution and the increased risks that accompany electrochemical reactions.

It is best to carry out galvanic work in a garage or workshop at mandatory ventilation or ventilation of the room. Special attention Care should be taken to ground the equipment. It is necessary to observe personal safety measures, namely:

The respiratory tract should be protected with a respirator.
Hands and wrists should be covered in tall, durable rubber gloves.
Shoes should protect against burns, and clothing should be covered with an oilcloth apron.
Be sure to wear special safety glasses.

Before starting copper plating work at home, you need to prepare necessary materials and equipment. You need to take care of the voltage and direct current source. There are many recommendations regarding current strength, the spread of which can be large. Therefore, it is desirable to have a rheostat with the ability to smoothly adjust the voltage and to gradually complete the process. The source can be a car battery or a rectifier with an output voltage of no more than 12 volts. For the first experiments it will be enough regular battery from 4.5 to 9 volts.

Then a container for the electrolytic solution is selected, preferably made of heat-resistant glass. In any case, all containers for electrolysis must be dielectric and withstand temperatures of at least 80 degrees Celsius.

Two large copper sheets are suitable as anodes. They must overlap the size of the workpiece. From chemical reagents you will need:

Copper sulfate.
Hydrochloric or sulfuric acid.
Distilled water.

Copper plating at home is deservedly popular because it adheres very well and reliably to steel products. The main condition is to correctly follow the process technology.

There are two ways to apply copper to the surface:

Placing the workpiece in an electrolyte solution.
Non-contact method. In this case, the product is not immersed in the solution.

The surface of the product is prepared and processed using fine sandpaper and a brush. After this, the part is washed in running water, degreased and washed again.

The stages of the copper plating process are as follows:

Two copper anodes are connected to the network to the positive contacts and placed in a glass jar.
A contact with a negative voltage value is brought to the processed product and suspended freely between the anodes.
Connect the rheostat according to electrical diagram for the ability to regulate the current strength.
A solution is prepared in correct proportions. For 100 g of distilled water you need 20 g of copper sulfate and 2-3 g of hydrochloric acid. Instead of hydrochloric acid, you can use something else.
The solution is poured into a container with copper plates and the part so that they are completely hidden under the surface of the solution.
The voltage source is connected. Using a rheostat, the required current is achieved at an approximate rate of 10-15 milliamps for each square centimeter of part area.

The whole process takes approximately 15-20 minutes. After turning off the power source and cooling the solution, ready product with a copper layer on the surface is removed from the jar.

This method is interesting because it can be used to process not only steel objects, but also those made of other materials. For example, aluminum and zinc. The process order is as follows:

From stranded copper wire a “tassel” is made. The end of the wire is exposed. A kind of brush is created from copper wires, which is then attached to a wooden handle holder.
The second end of the wire is connected to the positive contact of the electrical circuit.
A standard electrolyte solution of copper sulfate and hydrochloric acid is poured into a wide container.
The pre-cleaned and washed metal workpiece is connected to the negative contact and placed in an empty container.
An improvised brush is dipped into an electrolyte solution and passed over the surface of the workpiece without contact. This action is repeated until the result is obtained.

When the part is completely covered with a layer of copper, the power supply is turned off and the process is completed. The part is rinsed in water and dried.

Cutlery made from aluminum is often renewed using copper electrolysis. If you have no experience in carrying out this process, then you can practice applying copper to aluminum plates. Procedure for carrying out the process:

Electroplating is an electrochemical method of giving an object a certain shape by depositing metal on it. Most often, this method is used when processing non-metallic objects with metal or when making copies of jewelry.

If during electroplating the product does not have electrically conductive properties, then it is first coated with graphite, sometimes with bronze. The master then makes a cast of the copy and begins the galvanic process. The cast material used is gypsum, graphite or easily melting metal.

Electroplating is a very interesting and cognitive process, but it is related to active substances which may be harmful to health or damage property or environment. Therefore, before you start electroplating with your own hands, you need to take all safety measures, study a little theory of the process and the behavior of chemical reagents.