How to blacken metal at home. Burnishing a knife in citric acid

All metal objects (nails, fasteners, tools) turn black and rust over time. To avoid this they came up with the idea of ​​steel bluing. Thanks to this, the steel looked much better in appearance and was more protected from rust.

Of course, real steel bluing is done in industrial conditions, obtaining a layer of iron oxide on its surface, which protects the metal from corrosion.

You can’t argue with industrial scale and quality, but you can also do bluing in a home garage. Apply a coating to steel objects that forms a film and will serve as protection. The quality is different compared to industrial oxidation, but due to lack of availability, we have what we have. Some methods have proven themselves in practice and are quite popular among craftsmen.

So, do-it-yourself bluing methods.

Cold processing: brush or bath?

In the arsenal of craftsmen there are many solutions that cause the formation of a dark deposit on the surface of the metal. During certain chemical reactions, the substances contained in the solution form a black film on the surface of the metal. The most well-known substance for cold bluing is “Parisian oxide”. With an improved formulation it is offered in trading network as Klever Schnellbmenierung (Russian equivalent - “Raven 3”). The substance containing selenium is applied with a brush to the surface to be treated, after which it is thoroughly washed off. The method is quite economical and does not require special expenses.

Rapid bluing can be used for parts that are not subject to high mechanical stress. Whereas high-quality steels with a chromium content of more than 3% are not recommended to be processed in this way. In addition, the blackening will be uniform only with extremely careful processing, after which polishing with a special paste is required.

It is much more effective to perform rapid bluing by immersion. The effect of this procedure lasts longer. In addition, the operation can be repeated several times. A detergent is used to remove the dye. After that, the workpiece must be wiped dry with a rag moistened with alcohol. If you now apply distilled water to the product with a brush, it will not roll off in drops, but will form a uniform film, indicating the absence of fat on the surface.

Hot processing: oil and fire

The ancient artisanal method of bluing, in which the part is first oiled and then burned with a blowtorch, has a number of advantages. The process is not accompanied by the release of harmful substances, is cheap and effective. And although oil firing is also not true bluing in the full sense, the resulting coating lasts on the surface much longer than with cold processing. Those wishing to perform thermal bluing should slightly heat the surface of the product and apply a very thin layer of linseed oil to it.

It is also fashionable to use olive oil or special weapons grade (for example, Ballistol). The advantage of the latter is its slightly alkaline properties, which do not have a destructive effect on the metal. Lignite and petroleum oils, as well as various paraffins, are suitable for these purposes. When slowly heated to 200-400 C, the light fractions evaporate and a dense oil film forms on the surface. Further gradual heating leads to the formation of first a brown and then a black color, which can no longer be removed. It is fundamentally important with this technology not to use too much oil to avoid stains.

The best results are achieved by using a mixture of twenty parts grease and one part sulfur. The latter contributes to the formation of a very dark layer of iron sulfide. Sulfur balm can be made from sulfur by dissolving it in a small amount of turpentine and then mixing it with linseed oil. The composition is distributed in a thin layer over the surface of the workpiece and subjected to flameless combustion, which leads to uniform bluing.

Exposure to oxidizing agents

Steel can also be exposed to molten oxidizing agents. Typically, nitrates and nitrites are used for this, which can be heated until they melt (potassium nitrite melts at a temperature of 395 ° C, and sodium nitrate melts at a temperature of about 270 ° C). Objects to be blued are dipped into the melts of these salts, and they acquire a black color. However, hot molten nitrites can cause organic matter to ignite and, in some circumstances, threaten to explode.

Nevertheless this method Quite widely practiced and suitable for processing cast iron, steel and even copper, which is then painted a rich red color. However, it should not be used on heat-sensitive or hardened products.

Instead of these rather dangerous substances, you can use hot salt or alkaline solutions, working temperature which are significantly lower.

Cold bluing recipes

1.1000 ml distilled water, 30 g ethanol, 20 g 69% nitric acid, 75 g iron (III) chloride, 20 g copper (II) sulfate
2. iron (II) sulfate: 30 g, iron (III) chloride: 15 g, copper (II) sulfate: 15 g, ethanol: 50 g, add water to 1000 ml
3.1000 ml water, 50 g isopropyl alcohol, 75 g 30% of hydrochloric acid, 75 g 69% nitric acid, 150 g iron (III) chloride, 30 g copper (II) sulfate
4.1000 ml water, 13.5 g 69% nitric acid, 4 g 30% hydrochloric acid, 4 g copper (II) sulfate, 170 g iron (III) chloride

The compositions are applied to the surface and left as long as possible for longer exposure under conditions of elevated temperature and humidity. The rust layer is then treated with steam and removed with a brush. the reaction is repeated until the desired result is achieved. It is often necessary to apply the product over 10 and even up to 20 times. In order to refresh old bluing, making it darker, an 8% solution of silver nitrate is sufficient.

Recipes for saline and alkaline solutions

1. 400 g sodium hydroxide, 10 g potassium nitrate, 10 g sodium nitrate, 600 ml water
2. 800 g of sodium hydroxide, 100 g of disodium hydrogen phosphate, 50 g of sodium nitrate, 100 ml of water.

The exposure time of these compositions should exceed 30 minutes. You should work very carefully and carefully. If the remaining alkali is not thoroughly removed, a coating may form on the surface of the product. Therefore, upon completion of processing, the product must be thoroughly rinsed, dried and lightly oiled.

Burnishing at home video

Blueing (blackening) of metal or steel is a coating of the surface with a special layer. It gives the product a certain color: black, blue or another. With this treatment, a beautiful tint appears. However, the method is widely used due to its practical benefits: objects coated with a special film are well protected from corrosion. The process has long been widespread in industry. Some people use bluing at home.

Bluening methods

There are several ways similar processing. In industry, bluing is carried out by changing the structural composition of the surface. Application - in a special way. At home, using such technologies is very expensive or simply impossible.

However, there are ways to blacken steel at home. This does not require industrial equipment. Everything you need can be found in the store. These methods are presented below.

Hot method

The hot method involves exposure high temperature . First, the metal is tarred, then burned, for example, with a blowtorch.

The principle is as simple as possible and has been used since ancient times. Even an ordinary kitchen stove is enough for work. Under the influence of temperature, the top layer interacts with oxygen.

Heating should be carried out slowly, gradually increasing to 400 °C. The surface first turns brown and then black. You will need oil: olive or gun oil. It is important to calculate its amount and not overdo it. Otherwise there will be stains.

The method at home is used less often than others due to technology. Although it has advantages:

• the protective effect lasts longer than with the cold method;
• harmless to health;
• requires low costs.

Before flameless firing, it is advisable to treat the product with a special composition, which includes:

• sulfur;
• grease.

The ratio of components is one to twenty, respectively. Apply as thin a layer as possible. As a result, the protective surface is very smooth.

You can check the quality of bluing in a simple way. Dip the brush into plain water and brush over the treated surface. There should be a film, but not a drop.

Cold way

Another processing method is cold bluing. Often used if products cannot be subjected to heavy loads. It takes a little time and also doesn't require a lot of money.

The idea is to coat the surface with a special solution, for example, Parisian oxide. Typically applied with a brush. For greater effect, the product is immersed in the solution. After the procedure, the product:

1. They wash.
2. Wipe with a rag. It must be moistened with alcohol.

Application of oxidizing agents

There is a method using molten oxidizing agents:

• nitrates;
• nitrites.

This blackening of metal at home involves immersion in a melt. The product remains in it until the surface becomes characteristic color. When working, it is worth remembering that the listed substances are hazardous to health. They can be replaced with the following solutions:

• hot salt;
• alkaline.

Some features

Blueing steel at home is not difficult. Oxidizing agents are used for processing and other metal products:

• cast iron;
• copper, which acquire an intense red color.

There are a number of features that it is advisable to remember:

1. If the products are heat-sensitive or hardened, then it is better not to touch them. Blueing will degrade performance.
2. To complete the process, you must remember to wash the product. special means. After drying, oil lubrication is sometimes required.
3. It is not difficult to find the necessary substances in stores, for example, saltpeter, citric acid.
4. It is also possible to remove blackening. For this you will need a special pencil.

Preparation is important:

1. Before starting, you need to clean the surface and sand it.
2. Degrease with a special solution.
3. Don't forget about rubber gloves to protect your hands. The processed product must not be touched.
4. Create ventilation, exhaust.
5. Select a vessel with suitable properties. The volume should allow the product to be processed to be completely drowned. A material that is not afraid of the substances used is suitable: glass, porcelain, stainless steel, earthenware.

As for color, it can also be important for some products. You can get different colors: from yellow to black, its shades. Therefore, strictly speaking, blackening and bluing are not the same thing.

To achieve the desired color, you will have to further clarify the components of the solutions or pay attention to the heat treatment mode. For example, one way is as follows:

1. Take copper nitrate (70 g) and alcohol denatured alcohol (30 g).
2. The salt is heated until it melts.
3. Add denatured alcohol.
4. The product is coated with this mixture.
5. Heat until the desired shade is obtained. The color will change.

Secrets of bluing

There are many recipes for bluing. Every master prefers his, someone may have tricks. In ancient times, blued steel recipes were often kept secret. Today you can find various recipes for every taste.

Cold bluing

The following example of cold bluing of a house can be given:

1. Take a liter of water (distilled), two types of acid: 30% hydrochloric (4 g), 69% nitric (13.5 g). Ferric chloride (170 g) and divalent copper sulfate (4 g) are also added.
2. The mixture is treated with the surface and left for some time. The longer the better.
3. Rust is removed using water steam and a brush.
4. Everything is repeated until the result is the desired one. Some do this up to 10-20 times.

Recipe with oxidizing agent

For example, the following recipe for an alkaline solution can be given:

1. You will need caustic soda (400 g), sodium nitrate (10 g), water (600 ml).
2. The mixture should act for 30 minutes or longer.
3. Then the surface is washed well, dried, and slightly oiled. If the alkali is not completely washed off, plaque will form.

Care should be taken during operation. Hot substances and chemicals can cause damage to health or damage property. It is important not to forget about the correct selection of containers, suitable clothing and basic safety precautions.

Blueing of metal is one of the most popular ways today to paint a metal product, with the purpose of decorating any edged weapon, for example, a knife, or simply preventing the appearance of rust and corrosion on a steel item.

The most common methods for bluing steel are:

1. A chemical method, when cleaning and painting a product is achieved by exposing the metal to various chemicals.
2. A mechanical method in which powder or paint is applied to a product by methods such as enameling, sprinkling or hammering.

Due to the fact that the chemical bluing method is simpler than the mechanical method for home use, it more often used by amateurs to apply blackening to a steel product, exquisite pattern or unusual colors.

The procedure for chemical bluing of steel at home step by step (general diagram)

The most common methods of chemical bluing

Alkaline method

This is one of best options for bluing metal at home, which you can do yourself. Before you start you will need:

• Protective equipment such as face mask and gloves.
• Water.
• Sodium nitrate.
• Digital scales.
• Sodium hydroxide.
• Container made of stainless steel.

The bluing procedure is done as follows: during the work, the product will be boil in an alkaline solution, That's why prerequisite The success of your endeavor will be maintaining the temperature required for good luck operations. In other words, you must ensure that the liquid is constantly in a boiling state. The procedure is carried out over 1.5 hours, during which you need to remain close to the product, periodically adding water to the container as needed.

The next step is to degrease the item being blued to remove any fat or oil that may negatively affect the resulting color products. Complete immersion of the object in the solvent helps protect against possible color differences. And at the last stage, a fat-free product, for example a knife, must be washed with soap.

Oil bluing

This method is characterized by small monetary costs and is available for use at home. To complete it you will need the following:

• Alcohol lamp.
• Olive oil.

First, you will need to polish the surface of the product with sandpaper. This is necessary in order to remove various roughness and irregularities from the metal, which can spoil the appearance of the item after bluing. Then, having thickly coated the surface with olive oil, you need to start heating the steel or metal over an alcohol lamp. Any exact time firing in this case cannot be specified, main criterion successful operation - make sure that the product has acquired an even black color. After this, allow the item to cool to room temperature and remove excess oil with a napkin or cloth.

Burnishing with egg white

An unusual, but nevertheless effective and intriguing method of bluing that is easy to do at home. You will need:

• Egg white.
• Soda solution.
• Source of fire.

First of all, you need to prepare the surface for blackening. To do this, the product is washed in a soda solution, dried and then covered with egg white, which was previously beaten. Further, it is necessary to ensure proper conditions for complete drying of the surface. To accomplish this goal, the item is placed in a dark and cool place for 2 days. Looking at it after two days, you may notice that the white of the egg is tightly stuck to the metal. Now, to remove the protein from the surface, you need to heat the metal on a fire source until it turns red. After the item has cooled and the egg white has crumbled, you will find that your item has acquired a rich black color.

How to burnish steel surfaces correctly?

Please note that the answer to the question of whether the blued finish of your product will be of high quality or not can only be answered by analyzing the following criteria:

1. How well did you clean the product before the procedure?
2. What is the structure of the metal layer on its surface.
3. What is the condition of the surface of the steel that will be blackened?
4. Is the result of preliminary thermal or machining products.

In order for the results of bluing to please your eyes in all cases, during the preparation process and directly during the blackening work, you need to adhere to several simple rules. Firstly, carry out this procedure only when any rooms where there is good ventilation. Since chemical bluing involves the use of numerous mixtures that can be harmful to human health, be sure to take care of the supply fresh air to the workplace.

Secondly, equip the room with the necessary equipment and fixtures and take care to remove any flammable, fire and explosive substances and objects. Thirdly, keep the bluing room clean, as dust settled on the product can ruin the result of your work.

Fourth, stick to the already proven sequence of actions. If you notice that the steps you have taken are not conducive to success in blackening the metal you are interested in, change your actions by first testing new products on samples. Fifthly, do not try to burnish large or massive objects at home. The larger the working surface, the more difficult it is to obtain the desired result without the use of professional tools. Sixthly, do not forget about safety and take care of purchasing a set of protective equipment for yourself and your loved ones.

Additional processing of blued metal

After finishing painting a metal product, check to see if the surface of the product has a darkened or dull appearance. If you find this, then, as a rule, this is caused by the fact that the object was poorly polished and there were roughnesses that were invisible to the eye. In such cases, it is common to re-sand and polish the surface, then rinse the metal in water and allow it to dry.

What to do if you want to give the metal additional shine, you want it to shine dazzlingly when viewed under a light source? For polishing large or long metal pieces Usually they use cloth or suede; for small things you can try using a sanding wheel. After completing the polishing work, you need to consolidate the result. To do this, paint the surface of the product with varnish.

How to get a faded color?

To achieve a faded color on the surface of your product, you need to know very well at what temperature it appears and what duration of heating is necessary to fix it on the metal. Main condition: Flame firing must occur for a strictly defined time. Therefore, if you want to refine your product with a tan color, choose a small item, because on gas stove or a blowtorch, it will be almost impossible to heat a large area of ​​metal evenly.

Once you have achieved the desired color, immediately remove the product from the heat and let it cool. Then rub it with oil to set the color.

Initially, bluing of weapons was purely practical, protecting the metal from corrosion. Today, coating is also used to return the metal to its original appearance Moreover, blackening looks much more impressive and less noticeable in hunting conditions than metallic shine.

The concept of “blueing” came to us back in 1880, when it was often practiced by the best gunsmiths of that time. Then and now it's best method finishing of high-quality double-barreled shotguns and modern piece rifles.

Professional and amateur hunters, as well as those who simply take care of their weapons, resort to in various ways bluing of weapons. Held this process, both from specialists and at home. What we get as a result:

• The product is completely protected from corrosion, because rust does not form on the blued layer;
• the product looks more presentable;
• when hunting in sunny weather, the black barrel of the gun is not noticeable;
• resistance to abrasion and other mechanical damage.

If you were not lucky enough to become the owner of a blued weapon initially, use one of the many methods and overcome this unfortunate misunderstanding.

Features of technology and methods of bluing weapons at home

The bluing process is essentially a chemical reaction, so it is carried out in special conditions and in compliance certain rules. The room in which manipulations will be performed must be well ventilated or have a powerful exhaust hood. To work with acid and other chemical compounds, do not use metal containers, only earthenware, porcelain or glass.

Materials for processing can be sandpaper, powdered pumice, and fine sand. With their help, the surface of the weapon is thoroughly cleaned and polished. Liquids must be used in the correct proportions, because... most formulations have chemical basis and may cause damage to the weapon.

Regardless of the bluing method, it is necessary to prepare the following tools and materials:

• steel wool;
• latex gloves;
• protective glasses;
• cleaner;
• weapon oils (lubricating and cleaning);
• applicators (cotton swabs, rags, brushes, toothpicks).

It is impossible, as experts say, to perform high-quality bluing at home. This is especially true for the oxidation of steel, which requires industrial conditions.

Home metal processing methods include cold, hot, and oxidizer bluing. Let's look at the features, as well as the advantages and disadvantages of each of them.

Cold bluing weapons

This method is widely used among home craftsmen. If the weapon is not subjected to high mechanical loads during operation, they can be cold blued. Cold bluing is carried out in a bath or special container. It is optimal for it to be made of wood or galvanized.

Burnishing takes place without heat treatment using various solutions. There are ready-made mixtures on sale for applying to metal using a brush. For example, the composition “Raven 3”, “rusty varnish” or “Parisian oxide”. “Rusty Lacquer” is a rare mixture, which if anyone has it, it is only thanks to old stocks. It is not recommended to make the mixture yourself without some experience, because... this occupation is dangerous and labor-intensive.

The prepared compounds are applied to the surface using a brush, after which a protective black film is formed on the weapon. It is necessary to ensure the uniformity of the layer and the penetration of the weapon bluing liquid into all hard-to-reach places. After finishing the work, the part is washed and polished.

There is another method - complete immersion in a weapon bluing agent. Immersion in “rusty varnish” is the most effective and less expensive method. After all procedures are completed, the blued parts are thoroughly washed using detergents.

The advantages of the brush application method are obvious. The compositions do not need to be prepared, they are already prepared. Simple application allows even inexperienced beginners to blue a weapon, especially since there is no need to follow special safety precautions.

Their disadvantages include the difficulty of lubricating parts with a non-standard product configuration. After processing, the surface needs additional polishing. Cold bluing is not suitable for products subject to constant mechanical stress, because the resulting protective layer is quickly erased.

Hot bluing weapons

Many, especially experienced burners, prefer the hot processing method, considering it the most accurate and reliable. The coating made in this way is durable and lasts much longer.

The general principle of hot bluing is simple: heating-oiling-baking. In more detail it looks like this:

• the product heats up to a high temperature;
• Place it completely in the oil for 10-15 seconds or lubricate it with a cotton swab generously soaked in the composition. The best effect is achieved with flaxseed and hemp oil. Machine oil and drying oil behave worse;
• after application, excess oil is allowed to drain naturally so that there are no smeared streaks;
• The oiled part is baked using a blowtorch, gas heater or old stove. A hair dryer will also work.

Baking continues until the surface of the part begins to change its color to black. It is recommended to repeat the procedure of soaking in oil and baking 2-3 times to achieve a high-quality result.

Hot bluing has more advantages than disadvantages. Firstly, this is a method that has been tested for decades. Secondly, the coating allows you to keep the weapon intact for a long time. Thirdly, the absence of chemical impurities eliminates the presence of harmful fumes. The disadvantage of this method is that it requires minimal experience to achieve an even, spot-free coating.

Oxidizing agent treatment

The oxidation method is often carried out by specialists in laboratories where the necessary reagents can be found: potassium nitrate and sodium hydroxide. The product is pre-prepared. Using steel wool, surfaces that will be blued are processed. Next comes the dyeing process itself:

• for 10-15 minutes the weapon is placed in a cleaning composition to remove lubricants, dirt, oil. Trisodium phosphate, denatured alcohol, or kerosene can be used as a bluing cleaner;
• rinse off the cleaner under running water cold water, but keep the product for longer than 2 minutes. Kitchen detergent is washed off with hot water;
• Using a steel wire, the weapon and its individual parts are immersed in the prepared solution. Small elements can be loaded using a sieve. The solution for hot bluing is heated to a temperature of 135 degrees. The barrel of the weapon is immersed at an angle. This way you can avoid the formation of air inside;
• the sieve with small parts needs to be moved from time to time so that they are evenly colored;
• The soaking time in the bluing solution ranges from 15 to 30 minutes. You need to navigate by color. When the product acquires the desired shade, it is removed and washed in cold water;
• the washed parts and the main product are placed in a container of boiling water to remove residues chemical reagents. Keep the weapon in boiling water for up to 15 minutes. Parts with figured carvings up to half an hour;
• Finally, the blued parts are placed in a reservoir of water-repellent oil. During operation, it will protect products from corrosion and various contaminants.

The advantage of bluing by oxidation is that the result is quite durable. Knives treated in this way become protected without destroying the hardness of the metal. The disadvantage is that the method is quite expensive and is not suitable for those who do not have at least a superficial knowledge of chemistry.

Criteria for choosing a bluing method

Before you begin the bluing procedure itself, you need to decide which method will be most effective in your particular case. This is done according to several criteria.

1. The degree of wear of the previous bluing. If most of the coating remains, it can be renewed using alkaline bluing or cold bluing. If more than half of the coating has been erased, it is recommended to completely remove the old layer and carry out the processing procedure again.
2. Age of the weapon. Antique samples were processed using thermal bluing. Unfortunately, today this method not in demand due to the length of the process. You can repeat it at home using special preparations available for sale, or seek help from a specialist. There are some rules here. Ancient weapons with silver soldering cannot be treated thermally, because... salts can dissolve silver.
3. The rationality of one or another method of bluing in terms of cost. It is at least unreasonable to bury a cheap barrel using an expensive thermal method.
4. The cost of the bluing methods themselves. Here they are guided by common sense and foresight. If now an expensive coating method seems unnecessary, then in the future such savings may result in expensive restoration. Also, cheap bluing methods will protect the weapon for a short period of time, and the procedure will need to be repeated over and over again. And if you calculate the cost of regular events and one, but for a long period, then the second option will not seem so expensive.

In any case, the choice of method depends on the capabilities and preferences of the weapon owner.

Safety rules and regulations

Any manipulation with weapons requires compliance with safety precautions, especially for manipulations at home. Failure to comply with the rules of conduct is dangerous to the health and life of not only you, but also those around you.

1. Before bluing your firearm, be sure to unload it and remove any woodwork.
2. Solutions with chemical components can emit harmful fumes, so the entire process should take place in a well-ventilated area.
3. Select special utensils and tools for bluing, keep them separate from household equipment and wash them well after use.
4. Working with chemicals requires full protection to avoid burns.

Whichever bluing method is chosen, it requires preliminary preparation:

• cleaning the surface of the workpiece;
• thorough surface grinding;
• degreasing, after which you need to continue working only with rubber gloves;
• using only those products that are suitable for bluing weapons at home;
• final processing of the product.

When starting bluing, you should strictly follow the order and sequence of actions to prevent damage to the weapon.

Applying a paint coating to the surface of metal products is a way to make parts beautiful and protect them from deformation or the formation of a corrosive layer. There are not only special paints, but also a bluing method, which is characterized by the use of iron oxides during a chemical reaction. As a result, it is possible to obtain a surface with a unique appearance and strong resistance to external factors.

Features of metal painting

A huge number of dyeing methods have expanded the color base. Depending on the method of applying the paint and varnish coating and the oils, acids and varying degrees of heating used, it is possible to create any color, even lemon color.

All paint application options are divided into two types:

• mechanical;
• chemical.

When applying paint mechanically, various powders are used, which are sprayed, splashed, hammered in using special tools. This option is not distinguished by quality, beauty or uniqueness, but is appreciated by car enthusiasts due to its low cost. Besides, mechanical dyeing easy to do at any service station or even with your own hands if you have one necessary equipment.

The use of the chemical method requires experience and knowledge of the sequence of the entire procedure. The first thing to do is this is to clean the metal surface from old paintwork. Next, the damaged areas of the primer are restored, which are previously cleaned of rust. After the metal acquires an ideal surface, it is degreased. Small oil removal parts are placed in solvents such as gasoline, ethyl or ether. The treated parts are immersed in boiling water and only then subjected to chemical staining.

Applying a paint coating is not enough if you want the metal to acquire an elegant look and shine of the surface and remain so even with frequent use. This problem is solved by oxidizing the steel.

This procedure involves rubbing the surface with mixtures such as:

• nitric acid mixed with alcohol, water and copper sulfate in the form of sawdust;
• inky-nut-colored acid, including iron and antimony;
• silver nitrate with added water;
• olive oil with antimony chloride.

After applying one of these mixtures to a metal surface, it is subjected to heat treatment. The result of the work will depend mainly on how well the part was cleaned from grease, dust and dirt.

This method is often used to protect the weapon, automobile parts from scratches and chips. Protection can be achieved in other less effective but cheaper ways. For example, many people do metal bluing with oil at home, which, thanks to the crystalline structure of the protective layer of paint, penetrates and creates shine and an additional layer of protection.

If you are doing all the work yourself, then it is important to remember that after drying the painted metal will look darker than when wet. Therefore, taking into account such features, you need to adjust the color in an acceptable direction.

DIY blackening methods

Exists a large number of methods of blackening a steel surface. The most popular of them include the use of alkaline, acidic solutions or heat treatment. Each of these methods requires special equipment, but some options for bluing steel material can be done at home.

A simple, cheap and safe method involves processing metal using an alkaline material. For bluing with alkali You will need to additionally find and prepare:

• sodium hydroxide;
• sodium nitrate;
• water;
• digital scales;
• protective clothing.

The list of protection must include gloves, boots and a respirator. For the rest of the protection, old clothes will do. Some formulations require nitrate or phosphoric acid.

For processing metal parts Stainless steel utensils are required, otherwise chemical reactions with alkali may occur. Burnishing is carried out at a certain temperature, so the solution is first poured into a container and brought to a boil. The alkaline solution remains in this state for about an hour, only then the part is lowered into it. If you can’t immediately dip the entire metal part, you can add a little water.

Applying a protective layer using alkali requires compliance with all rules, including preparatory ones. The metal is first cleaned of dirt and debris, and then treated with solvents that degrease the surface. Without this point, the paint will not adhere well to the surface and will quickly begin to deteriorate.

There are strange and wonderful ways to blacken using butter or egg whites. Both methods are effective and are excellent for carrying out this procedure at home. Oil bluing, for example, is a cost-effective and interesting method of blackening steel. To do this, olive oil is applied to the surface of the metal, which has previously been slightly polished using fine sandpaper. Next, the part is heated over a fire with an alcohol lamp until the color changes. Remaining oil is removed with a simple rag. To add shine to the product additionally polished and ground.

Using egg white is no less effective method. First of all, the steel being processed is washed in a soda solution and dried. Then the surface is covered with a thin layer of whipped egg whites and the part is left to lie for two days in a dark place. After this time, the metal heats up to a red-hot state and a reaction occurs that paints it a rich black color. The hotter the part is heated, the faster and better the bluing process occurs, but you cannot bend it. Using this method in practice, it is easy to find a middle ground that will not reduce quality, but will increase the speed of work.

Oxidation of various alloys

Burnishing of aluminum alloys helps protect the surface from the spread of corrosion. A thin layer of protection firmly resists any external factors that affect the painted surface. Usage chemical compositions is the most popular method for applying such a coating.

The chemical method is immersion into a pre-prepared bluing composition, which includes components such as:

1. Sodium dichromate and chromic anhydrite.
2. Potassium hexacyonferrate, chromic anhydride and sodium fluoride.
3. Carbon dioxide and sodium chromate.
4. Chromium anhydride and sodium fluorosilicate.

All components are mixed using liquid and, according to the instructions, applied to the aluminum surface to be painted, where they enter into a chemical reaction on their own or by heating.

The process of blackening metal at home is not all, because after obtaining the required color, the aluminum must be processed to consolidate the result. First of all, after removing the parts, all the liquid must drain and only then the product is lowered into nitric acid. The oxide film is fixed, which will only enhance its qualities during drying at medium temperature. It is difficult to say exactly the oxidation time, because the black color can be different, and it depends on how long the part is in the chemical solution. After all the procedures have been completed, the surface is painted with special dyes to treat the blued surface.

Anodizing of aluminum parts

This method has become most popular when processing aluminum surfaces. The idea is to cover the entire area with a thin layer of passive insulation using simple components and tools.

The first step is to prepare a saturated electrolyte solution, similar to the procedure for chrome plating steel. Anodizing involves processing aluminum in a container of liquid where current is applied. A simple medium-power battery is suitable as a current source.

Aluminum parts, before being immersed in an electrolyte solution, should be degreased using solvents or simple washing powder. When exposed to current, a bluish-gray coating appears in the container if degreasing of the product was successful. Next, the aluminum surface is wiped with a solution of potassium permanganate, which removes plaque and makes the surface shiny and smooth. Aniline dyes of any color are suitable for further dyeing.

Although the process is considered the easiest method available, it still requires experience and practice. Therefore, for the first time it is better to practice on the working part of the ax or other unnecessary materials.

The protective layer that appears after bluing can make the surface durable and resistant to any mechanical and chemical influences, which is especially useful for equipment or machines that are constantly in use. Chemical oxidation of steel at home is carried out without the help of specialists, if you follow all the rules of the step-by-step instructions.

Artificial ventilation must be provided in the room where painting will take place, because small debris can fly in through open windows or doors and settle on the surface of the metal just during the blackening process. It is important to remember about dust getting on the product if polishing or grinding is carried out in close proximity to the drying part. The temperature in the room should be room temperature and constant regardless of the time of year outside.

Experts in the field of painting have long studied how to stain metal at home, so you should stick to the established procedure and change it only if it is incompatible with the material. They put their rules into practice only after a long study and repeated application of the new bluing technique.

The quality of blackening of a steel surface depends on several conditions:

1. The stained area must be in good condition. It is impossible to achieve the perfect bluing effect if the metal is rusty, has obvious deformations, holes, fractures, etc.
2. Any chemical compound comes into contact with the cleaned surface and therefore any dirt particles must be removed.
3. Quality also depends on the structure of the metal.
4. When all requirements for mechanical and thermal treatment are met.

These are the main conditions that have a direct impact on the connection of the chemical mixture with the steel or aluminum surface.

The difficulty of painting various parts mainly depends on their size and shape. Small items, weapon elements and machine parts can be easily coated in black at home using a simple earthenware, glass or porcelain container. Large objects will be difficult to paint without the use of special equipment. At a minimum, a small tap or hanging machine may be required to drop the metal evenly into boiling water or solution through which a current is passed.

Metal bluing is great way protect it from external damage and at the same time give it a piquant and unique look. This method is especially suitable for painting car parts, weapons or public objects. You can do everything yourself, but it is important not to forget about the rules of the bluing process and safety.