Do-it-yourself chrome plating. Features of chrome coating of various bases

You don’t have to be an experienced chemist to chrome plating parts at home with your own hands. This method accessible to the average craftsman, does not require professional knowledge and therefore remains a popular processing method. The technology allows you to obtain a shiny surface on metal, plastic, glass or wooden base, which does not lose its shine under the influence of air and water.

There are similar operations for obtaining an additional metal layer: galvanizing, nickel plating, silver plating. Chrome plating of parts (the process of applying chromium to a product) includes several functions:

1. Protective. The chromium layer is resistant to temperature changes; it improves the physical and chemical characteristics of the surface, protecting it from oxidation, giving objects (car parts, bicycles, devices) additional strength.
2. Decorative. The result of galvanization is an attractive appearance any vehicle. Decorative chrome plating beneficially transforms interior details - fastening elements of ceiling cornices, fittings (door handles or furniture), decorative stands, souvenirs.
3. Restorative. Extends the service life of the worn surface of shafts and bushings (if the wear depth does not exceed 1 mm), thereby increasing the service life.
4. Increases engine wear resistance internal combustion(deposited on rubbing surfaces), all kinds of stamps and dies, measuring instruments.
5. Improves reflective properties (chrome plating of headlight reflectors, production of spotlights, technical and household mirrors).

Chrome plating technologies

Chrome plating at home can be done in several ways:

• Galvanic (electrolytic) method. Chromium atoms from the electrolyte solution are deposited onto the surface of the workpiece under the influence of an electric current. The most popular method has a wide range of applications, including the creation of products with reflective properties. Galvanic deposition of chromium makes it possible to achieve high-quality coating resistant to mechanical and chemical damage.
• Chemical (catalytic). The method is based on the interaction of reagents and the recovery of chromium from its salts; electricity does not apply. The resulting layer is initially gray in color and needs to be polished. Chemical chromium plating, due to the presence of phosphorus among the reagents, makes it possible to coat products of complex shapes, including cavities, with a high-quality hard layer.
• Diffusion method (chrome deposition is carried out using a galvanic brush). Chromium plating of parts at home using the diffuse method is a compact processing method that does not require the organization of a bath. Control of the thickness and quality of the coating is possible directly during the operation.

Preparation of the workplace

Metallization with chromium is a chemical process accompanied by the release of toxic (carcinogenic) substances that are harmful to human health and natural environment. Therefore, for electroplating at home, a non-residential, impeccably ventilated room is selected. Best choice is a garage or detached workshop with efficient forced ventilation(with a hood). Consideration should be given to waste disposal.

Chromium electrolyte releases volatile compounds that can come into contact with and destroy any organic matter. Vapors are hazardous to the skin and mucous membranes. To protect against fumes, use goggles and a respirator mask.

Chrome plating at home is carried out in overalls, boots and an apron. Protect your hands with thick latex or rubber gloves. Before work, it is recommended to lubricate the nasal cavity with an ointment consisting of Vaseline and lanolin (in a ratio of 2 to 1).

Equipment

To carry out chrome plating with your own hands at home at a decent level, it is proposed to make some of the equipment from improvised materials. Items included in the electroplating chrome plating kit include:

1. Galvanic bath - a vessel made of plastic, glass, polyethylene or propylene (resistant to prolonged exposure to aggressive environments); Enameled will also work. For small items, a glass jar is ideal. For high-quality electrolysis, the selected dishes must be thermally insulated (placed in wooden box, upholstered inside with fiberglass with additional insulation mineral or glass wool).
2. Power source - must have the following characteristics: current 50 A, permissible voltage 12 V, total power no more than 1 kW.
3. A heating device for electrolyte that can withstand contact with an aggressive environment (ceramic heating element) of appropriate power. It is permissible to use an external heater.
4. Thermometer calibrated to 100° Celsius.
5. A lid that is hermetically sealed to the vessel with the electrolyte (not metal).
6. Electrodes – the anode is a lead plate. It is immersed in a container, the cathode is attached to the chrome-plated sample. It is convenient to use a clamp holding the part as a cathode. The latter is placed in the electrolyte so as to prevent it from touching the walls, bottom and anode.

Power supply

For electroplating in home laboratory A grounded source is suitable direct current with adjustable voltage 1.5-12 V, with a maximum current of 20 A (it is convenient to use a rheostat to adjust the output power).

The cross-section of the connecting wires is selected taking into account the maximum load (current). For chrome plating of small parts, wires with a cross section of 2.5 mm are used.

Composition and method of electrolyte preparation

The mixture for chromium precipitation contains:

• Distilled (from a pharmacy) or tap (boiled and settled, ideally filtered) water.
• Chromic anhydride (CrO3), at the rate of 250 g per 1 liter of water.
• Sulfuric acid (H2SO4) – 2-2.5 g/l (with a specific density of 1.84 g/cm3).

Preparation procedure:

1. Fill the vessel halfway with water heated to 60º C.
2. Add chromic anhydride; achieve complete dissolution by stirring.
3. Add the remaining water, carefully add acid, stir.
4. The electrolyte is kept for 3.5 hours at rated current (to equalize the density).

If all the rules are followed, the electrolyte turns dark brown, after which the mixture settles in a cool room for 1 day.

Surface preparation

The better the surface of the product is prepared, the less problems will arise during galvanic chrome plating and the coating will be of better quality.

• Preliminary mechanical and chemical cleaning. Are deleted heavy pollution(varnish, paint, rust stains). Rust from the metal surface can be removed by etching in acid, and remaining paint can be removed with sandpaper.
• Fine cleaning. Traces of dirt are carefully removed with a clean piece of cloth.
• Degreasing. The procedure requires a solution of 150 g of sodium hydroxide, 50 g of soda ash and 5 g of silicate glue (calculated per 1 liter of water). The item is kept in the solution for 20-60 minutes at 90°C; time is affected by the complexity of the form.

Chrome plating

1. The electrolyte is heated to 52±2°С (during the process a constant temperature regime).
2. A part with an attached cathode is placed in a vessel (with an anode attached) and heated until the temperatures are equalized.
3. Voltage is applied. The deposition time ranges from 20 minutes to 1-2 hours, which is determined by the shape of the object.
4. The part is removed, washed in distilled water (several times) and dried for 3 hours; Do not touch it while drying. Using this method, parts made of steel, brass, and bronze are chrome-plated.

Method for chrome plating plastic at home

To ensure chrome plating of plastic at home, it is advisable to make an electroplating brush (the method is also applicable for metal products):

• Bristles (suitable from paint brush) with a diameter of 20-25 mm is tightly wrapped with lead wire. It is fixed at the end of a cylindrical vessel, which is filled with electrolyte. It is convenient to use a container made of plexiglass (control the solution level). A diode is attached to the other end.
• The circuit uses a step-down transformer (12 V, 0.8-1 A). The negative side of the transformer is attached to a chrome-plated object (with an alligator clip). The plus goes to the anode of the diode, the cathode of the diode is connected to the bristle winding.
• A layer of liquid is applied to the surface to be treated with smooth, uniform movements; each section is passed with a brush at least 20 times, without lifting it from the surface.
• Once electroplating is complete, the item is washed and dried; dirt is removed with a compressor.

Video: unique technique chrome plating at home.

Possible defects and their causes

1. Chrome does not settle on the workpiece. The reason may be poor contact, oxide film or short distance between the electrodes. The process is disrupted due to incorrectly selected conductor cross-sections, excess sulfuric acid, low current density or too hot electrolyte.
2. The surface shine is absent or uneven (with darkening and spots). The temperature regime of the electrolyte and the concentration of the reagents are not observed. The current has been exceeded.
3. There are growths of metallic chromium on the corners of the object. Current density is higher than recommended.
4. Defects (sinks) on chrome plating. Poor cleaning. Excess current, hydrogen retention.
5. Peeling of coating. Poor degreasing, surges in voltage, current density or temperature.

The process of how to do chrome plating of parts yourself is attractive due to its accessibility and obvious cost savings. No need to have special education to chrome-plate a set of wheels or the entire body, or get original handles for doors or cabinets.

Decorating plastic with a layer of chrome in a home workshop is no more difficult than metal. The key to a brilliant result will be thorough compliance with safety rules and attention to the details of the technological process.

Chrome plating of various parts is often used when tuning cars. Thanks to this treatment, the products become silvery and shiny. Moreover, it provides protection against corrosion. If you have experience and knowledge, you can perform chrome plating at home yourself.

Necessary materials and equipment

To apply a special coating to parts you need have the appropriate equipment:

• plastic or polypropylene bath;
• a rectifier providing a voltage of 12 V and a current of 50 A;
• an acid-resistant heater that will heat the electrolyte;
• thermometer with a scale up to 100°C.

For reasons of economy, it is better to choose a small bath for immersing parts. You can use a rectangular plastic tray instead of this container. To prevent the solution from starting to evaporate during storage, it is necessary to prepare a drainage tank or a reliable sealed lid.

Often acts as a rectifier Charger, used for car batteries. This unit is ideal for chrome plating very small parts.

A must prepare electrolyte. Its components are:

• distilled water;
• sulfuric acid (2.2–2.5 g/l);
• chromic anhydride (220–250 g/l).

Additionally, you will need hydrochloric acid, sheet lead, and acetone.

To apply special protective covering, you must adhere to several rules. Thus, only products can be processed made of nickel, copper or brass.

To perform chrome plating you will need a special electrolyte. It's easy to prepare. To do this, dissolve a small amount of chromic anhydride in water, and then pour in a thin stream of sulfuric acid. Before processing the first part, you should hang a clean metal plate, and then work the electrolyte for at least half an hour. When the shade of the solution becomes burgundy rather than bright red, you can begin chrome plating the parts. You should also ensure that the solution temperature reaches 45°C. When choosing the current strength, the surface area of ​​the parts is taken into account.

Features of self-chrome plating

Many people believe that only real professionals can chrome parts themselves. In fact, this kind of work is not difficult to do if follow simple recommendations.

• First of all, you need to choose appropriate place. The best option There will be a ventilated spacious utility room. A large balcony would also be suitable.
• Particular attention should be paid to the use of protective equipment. We are talking about a respirator, safety glasses and gloves. In addition, you will need an apron.
• Before starting work, you need to prepare the equipment. This is especially true for capacity. Its function can be performed by a plastic bucket or a 3-liter glass jar. If large parts with complex configurations are subject to chrome plating, you should select a larger container.
• Since chrome plating involves preserving high temperatures, it is important to take care of the availability heating element. For these purposes, you will need a heating element, as well as a thermometer with a scale of up to 100°C.
• For chrome plating, you need to prepare clamps and a bracket with which you can secure the parts.

Possible defects and their elimination

If you decide to chrome parts for the first time, then even after watching several videos and studying the basic recommendations, mistakes are possible. A layer of chrome with defects can be removed using a solution of hydrochloric acid, then the parts are washed in water and the procedure is repeated.

For more avoid making mistakes, you need to know their reasons.

Caring for chrome parts

A special feature of chrome-plated elements is their shine, but it may disappear during use. To prevent this, it is necessary provide surfaces with proper care.

Thanks to development modern technologies, you can do almost anything right in your own home, from wooden crafts and ending chemical experiments. And today we will talk about the process of chrome plating at home. You don't have to look far to understand what chrome is: car handles, phone panels, bumper trims, etc. IN Soviet times the parts were covered conscientiously, so the Zaporozhets with chrome elements produced 40 years ago will still retain its shine. With today's cars and accessories the situation is completely different. Coating, if necessary, in specialized centers is expensive, and they are not always available. Therefore, if there is such a need, you can do chrome plating of various parts at home.

Chrome plating methods

Eat various ways applying chromium to a part, for example, spraying. But it requires presence specialized equipment: a compressor, a paint sprayer, and this is very expensive. Therefore, we will not consider this method of chrome plating, but will focus on galvanizing.

Of course, everything is not as simple as we would like. The main thing is desire, and everything will work out. To start working at home, you will need galvanic bath. With its help, you can apply chromium to parts made of steel and copper. Assembling such a bathtub is not difficult, just look at the picture below.

Indeed, nothing complicated! With one small exception, we do not need a copper plate; it is replaced by a lead one. As for the capacity, it is best to use glass jar, but if the parts are not included in it, you can use a plastic bath. Under no circumstances should you use an iron basin or something similar.

Preparing parts for chrome plating involves completely degreasing them. In addition, if you plan to coat steel elements, then first you will have to cover them with a layer of copper. Only under such conditions is guaranteed high-quality application of chromium to the surface of the part.

Electrolyte preparation

In order to chrome plating elements, you need to prepare an electrolyte solution. There are several types of solutions, depending on what we ultimately want to get. If the element to be coated is not subject to heavy loads and is protected from external influences, then it is quite possible to use the electrolyte composition for soft chrome plating. It includes:

• Chromic anhydride, in an amount of 400 g, this will be quite enough;
• Concentrated sulfuric acid - you will need about 4 grams;
• Distilled water, about a liter.

In such a bath chemical reactions should occur at a temperature of no lower than 25 degrees and no higher than 65. The current density must be maintained at 20-50 A/Dm2.

If you plan to chrome-plate elements that will then be used in rather aggressive environment, then it is better to use a different method of preparing the electrolyte. By the way, if you are going to chrome the external parts of the car body (moldings, door sills, front bumper), then only this option will suit you:

• The same chromic anhydride in the amount of 250 grams;
• Concentrated sulfuric acid – 2.5 grams;
• And distilled water, about one liter.

The water temperature and current density should be the same as in the previous version of electrolyte production. Under such conditions of chrome plating, the coating is more rigid and less susceptible to external influence(at correct application, should not be scratched by a knife).

The electrolyte is prepared approximately like this: water, a little more than half a liter, is heated to 75 degrees, and chromic anhydrite dissolves in it. Then the rest of the water and sulfuric acid are added. Afterwards, the composition is poured into the bath and an electric current is passed through it - this is necessary to saturate the solution with chromium ions. The cathode current density at this stage should not exceed 5 A/dm2. You can find out whether the solution is suitable for use by its color. If the solution in the jar is dark red, then it is too early to use the solution, but when it turns dark brown, the preparation can be stopped. Let it sit for about a day, then proceed to chrome plating.

Chrome plating of parts

Before starting the process, the solution is heated to 50 degrees, all elements are lowered into it, and only then electricity is connected. The process of applying chrome to your part takes place within 1-3 hours. The process is long, so there is little point in watching it. After the part has spent an hour in the galvanic bath, you can remove it and test the coating for strength using a knife. If it is scratched, then it is necessary to lower the part back for further chrome plating and slightly change the current strength.

When the coating process is finally completed, the part must be rinsed in water and dried. Some experts recommend boiling the part on gas and then drying it in the oven at a temperature of about 120 degrees. Only after this can you put it in its place. Do not neglect these tips, remember that chromic anhydride is a strong poison! Therefore, do not use the pan in which you will boil the parts anymore. Do not pour the solution into the street, into the river, or where children can get into it. Be careful when handling these items.

As you can see, the process of applying chrome does not require special skills; you only need strict adherence to technology and safety measures. And if you are planning to do chrome plating in your garage on a small scale, then think in advance about how you will dispose of the waste, because simply pouring it on the ground is a crime under criminal law.

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The spectacular exterior of the car excites almost every car enthusiast. Therefore, many car owners perform various types tuning in order to make your car special, to distinguish it from the mass of others, to give it individuality. One of the common types of tuning is shiny or nickel, which is used to coat various parts in the car's structure. On many cars we can see chrome inside and outside, a shiny radiator grille, etc. Therefore, chrome plating at home and in the factory is in great demand among car enthusiasts.

Technology of chrome plating of car parts

Due to the widespread popularity of such tuning, car enthusiasts often have questions about where and where parts can be chromed. You can do chrome plating by contacting specialists in this field - anyone who has encountered a similar problem knows about this. However, not everyone wants to give such work into the wrong hands. The reasons may be financial considerations or the desire to tune your car yourself. Therefore, there is a category of drivers who are interested in chrome plating themselves at home.

Some general information

Chromium plating is the saturation of chromium by diffusion or its deposition on parts in an electrolyte under the influence of electric current.

This is done for decorative purposes or in order to reduce the likelihood of corrosion and increase hardness. As a rule, metal and plastic surfaces are chrome-plated - technology allows this.

Electrolytic bath

Do-it-yourself chrome plating at home is a complex, time-consuming procedure, but quite doable. Many craftsmen have mastered chrome plating at home. They successfully use it by tuning parts in the design of their car. Let's take a closer look at how you can do this kind of work at home.

Preparing the workplace and equipment

Chrome plating at home requires a specially equipped workplace. Before you make your first attempt, you must fully equip the site and ensure that it meets all safety requirements.

A by-product of chrome plating at home is fumes that are harmful to human body. Therefore, it is very important to take care of the presence of high-quality ventilation - it must be there.

Chrome plating at home requires the following things:

• 3 liter glass jar;
• a plastic bucket or basin where you can place the jar;
• insulated wooden box with thermal insulation from mineral wool or fiberglass;
• thermal electric heater;
• a thermometer designed for temperatures from 1 C to 100 C;
• sheet of wood or plywood;
• a cathode in the form of a clamp and an anode in the form of a rod or plate;
• a retainer that will help ensure the “suspended” state of the part in the jar. This is necessary in order to chrome it evenly in all areas.

Before you take the first steps to prepare the electrolyte, you need to put on the following protective clothing:

• thick apron;
• latex gloves;
• protective glasses;
• respirator.

Chrome plating plastic bumper

Electrolyte preparation

Let's talk about how to make an electrolyte. To do this, you will need to follow the algorithm below:

• fill the jar with water heated to 60 C;
• add and thoroughly stir chromic anhydride at the rate of 250 g per 1 liter of water;
• pour and stir sulfuric acid at the rate of 2.5 g per 1 liter of water;
• drive the solution through electric field for 3 hours. The current should be 6.5 A per 1 liter. The readiness of the solution will be indicated by its burgundy color;
• leave the electrolyte for 24 hours.

Electrolyte preparation

Preparing the surface

Before chrome plating parts, they should be properly prepared. To do this, subject each part to the following operations:

• remove dust, dirt and rust;
• wash and dry thoroughly;
• Perform complete degreasing by wiping the surface with gasoline.

Preparing the surface for chrome plating

Chrome plating process

Chrome plating of plastic at home is no different from working with metal surfaces.

Do-it-yourself chrome plating of parts occurs according to the following algorithm:

• heat the electrolyte to 50 - 60 C;
• place the parts in it so that they are “suspended” and do not touch the edges of the container anywhere;
• apply voltage;
• after the process is completed, finished goods wash and dry thoroughly.

The result of chrome plating of body elements

Conclusion

You can coat products with chrome not only at the factory, but also at home. The technology is not simple, the process is very labor-intensive, but it is possible. Chrome plating plastic at home is no more difficult than metal - anyone who has independently tuned their car knows this.

For the work to be successful, you need to follow every detail technological process and safety requirements. If you make a mistake, it will affect the quality of the coating. But you can fix this by doing the work again.

Various items coated with chrome plating look beautiful and are often used to decorate motorcycles, cars or sports bikes. But few people think that chrome plating of parts is necessary not only to give beauty to the product: with the help of various types this process can be applied to metal parts additional qualities, provide protection against corrosion.

What is the application of chromium to a surface?

All types of chrome plating according to their intended purpose can be divided into:

• decorative;
• solid.

Aesthetic direction

Decorative chrome plating is carried out in order to give the part a stylish look. beautiful view. Very often decorative chrome plating is used for tuning various parts car or to create souvenirs and beautiful household items. Well-carried out metallization, in addition to decorative qualities, may have protective properties. Decorative chrome plating technology can be of the following types:

Hard chrome plating option

Hard chrome plating is often used for the following purposes:

According to the technology of sputtering hard chrome coating, we can distinguish different methods.

Galvanic

With this application of chromium, the product is immersed in a container with a reagent containing all the necessary components and heated to a certain temperature. A transformer is connected to it using a set of electrodes and a physical and chemical process occurs when reagents are created on the surface under the influence of current protective film. The thickness of such a film depends on the galvanization time and the magnitude of the current.

Calculation of process parameters is carried out depending on:

• type of metal (copper, iron or aluminum);
• degree of wear (new or damaged);
• nature of operation (shafts, rods or engine cylinders must be processed to the maximum).

In addition, the temperature of the reagent affects the calculation: the higher it is, the more active the reaction occurs.

Catalytic

Catalytic chrome plating involves reduction using silver salts and ammonia. This method well restores and protects from wear those things that are not subject to mechanical stress, for example, mirrors made of aluminum and copper or other household items. This chrome plating is often done manually or in private workshops using a portable chrome plating machine.

You can also paint the car body using the catalytic metallization method by contacting a workshop that has the appropriate apparatus. There they will be able to do metallic painting of the body, choosing the color in accordance with what is indicated in the title. The cost of the work will be about the same as with regular painting, but this automotive coating will make the metal impervious to corrosion. Sputtering can be carried out not only with chromium, but also with copper, zinc or aluminum.

Vacuum

Another option is vacuum chrome plating. This chrome plating process is only possible in factory conditions, in special vacuum chambers.

The principle is that a product coated with a reagent (usually chromium, but it can be copper or zinc) is placed in a special chamber. Air is pumped out of the chamber, negative pressure is created, and the reagent begins to interact with the base. Calculation of pressure and spraying time is carried out taking into account all components of the process:

• purpose of the part;
• the degree of its wear;
• the reagent used (copper, chromium, aluminum or combinations thereof).

chrome plating is one of the most effective. It is this method that most often protects and restores car parts such as engine shafts, rods and cylinders. It is recommended to process the barrels of hunting and underwater guns using this technology.

Thermochemical

The method is one of the most simple ways coating an item with a necessary component, such as chrome, aluminum, silver or copper. The use of this method for metallization of products in muffle furnace, perhaps only if they are not subjected to strong mechanical stress and have a heat-resistant base.

A mixture of metal chips and a flammable substance is applied to the base. Under the influence of high temperatures, substances burn, and the metal spreads over the surface. The disadvantage of this method is that the material is distributed unevenly, additional grinding is required, and the protective properties of the coating are weak.

What you need to chrome yourself

To do self-application chromium, copper, zinc or aluminum on the surface of various products, it is necessary:

1. Purchase or make equipment for chrome plating yourself and know the features of its use.
2. It is good to understand the chrome plating process, and also be able to calculate the time taking into account the reagent used and the nature of the material being processed, the degree of its wear.
3. Stock up on the necessary set of reagents for carrying out protective and restoration reactions, as well as for decoration.
4. Take training in chrome plating. Having such a certificate is important if you plan to use the equipment for a small business. He is mandatory requirement, because there are needed specialized knowledge: how to calculate the combination of all physical and chemical components, the use of which reagents is better to obtain the optimal result.

The basis of the spraying installation

The set of purchased equipment for chrome plating, as a rule, includes additional components that provide:

• cleaning from mechanical contamination;
• grinding;
• washing and degreasing surfaces.

Also, factory spraying machines often have a calculation table for most of the materials used in the attached instructions. This table is a convenient guide for beginners when they need to calculate the time and force of action of a reagent on various items, and especially on car parts when hard chrome plating is carried out. It is especially important to calculate the ratio of active spraying components, exposure time and temperature conditions for automotive parts subject to stress such as shafts, rods or cylinders.

For gun barrels, the requirements are less stringent, but it is advisable to carefully process them, because hunting guns are affected by powder gases, and underwater guns are exposed to high humidity.

Operating principle

Chrome plating equipment works simply. The installation performs a number of actions:

• cleans the base from unevenness and coloring residues;
• polishes until smooth;
• degreases;
• applies a layer of primer;
• subjects the item to heat treatment for more reliable adhesion of the primer base to the surface.

Chrome plating is one of the most optimal protective equipment for protection automotive components from overloads, and gun barrels from adverse effects. Chrome plating also makes it possible to create beautiful souvenirs or items for interior decoration.