Grinding and polishing metal with your own hands. How to polish stainless steel: ways and means to give an expressive shine. Disadvantages of traditional types of metal polishing

Polishing is the final process of manufacturing a part, carried out using various methods to remove the minimum layer of metal to achieve a mirror finish. These are interrelated physical, chemical, electrical influences, the choice of which depends on the type of material, the tool used and the characteristics of the external environment. The required quality is achieved by replacing abrasives and methods of exposure. Polishing time depends on the initial quality of the metal.

GOST requirements for metal polishing

Requirements for the quality of metal and coatings are defined in GOST 9.301-86. Surfaces must be free of pits, pores, rust, cracks after grinding, scale, and burrs. There are no regulatory requirements for the degree of gloss.

At enterprises engaged in metal processing, input control of surfaces is carried out. If necessary, the following is carried out:

• treatment with compressed air containing an abrasive (steel shot) (rust and scale are removed);
• metal brushing to remove oxides and pickling sludge;
• degreasing heated in organic solvents (chlorinated carbons) to remove grease;
• degreasing in alkali solutions (removal of mineral oils);
• degreasing in electrolyte (electrochemical).

At home, surfaces are wiped with a solvent, treated with a file or a grinder with a disk with the appropriate grain size.

Metal polishing class

The polishing class is determined by the surface roughness (roughness in microns) of a particular part. The roughness corresponds to the area of ​​use. In total, there are 14 purity classes, which are indicated in the drawings by an equilateral triangle. Numerical values ​​of roughness after metal polishing are specified in GOST 2789-59.

Metal polishing class

In industry, special instruments are used to measure the height of irregularities: profilers and microscopes. At home, the roughness is determined "by eye".

Existing metal polishing methods

The most common ways to polish metal:

• mechanical (abrasive);
• chemical (pastes, solutions);
• electrochemical (in electrolytes);
• ultrasonic.

Mechanical polishing of metal can be dry or wet.

The process can be carried out:

• manually;
• in semi-automatic mode;
• automatically.

Important! With manual processing, you can monitor the process and influence the result. It is impossible to achieve high quality and productivity.

Semi-automatic is a special equipment and a qualified specialist. Processing is carried out on metal polishing machines, technological parameters are changed manually. With automatic processing in batch production, human participation is not required. The work is carried out very quickly and with high precision. The amount of scrap is minimized.

Hand polishing small parts at home. The paste is applied to a rag and rubbed on the surface in a circular motion. For large surfaces, grinders (grinders) or drills equipped with nozzles of various grain sizes are most often used.

Various attachments can be installed on the disc. If the nozzle is made of felt or fabric, it is moistened with paste. A professional tool is used in auto repair shops, as it allows you to process surfaces of sufficiently large sizes. In small metalworking enterprises, machines equipped with polishing belts or felt (cloth) circles are used.

Mechanical methods also include abrasive technology for polishing metal in vibrating drums filled with dry abrasive or solution. Rotation and vibration can quickly reduce roughness. If the method is dry, then the solution is replaced with oak or ash sawdust, pieces of felt or suede. If a solution is used, then in addition to polishing steel balls, alkali can be added to it (for example, a solution of laundry soap), which speeds up the process.

But mechanical polishing has a number of disadvantages:

• there is a possibility of the introduction of abrasives into the structure of the metal;
• high installation and resource costs;
• processing consists of several stages;
• the process is difficult to manage;
• Requires a significant amount of manual labor and time.

Important! Chemical polishing has a higher potential, especially when it comes to elements of decorative interior decoration made of various alloys or expensive metals.

When using this method, metal products are immersed in solutions of a certain temperature. During the passage of chemical reactions, the roughness melts within a few minutes. There is almost no manual labor, power tools and metal polishing devices are not required. The surface is processed uniformly, the configuration of the part does not matter.

But there are also disadvantages. Mirror gloss is not achieved (the surface is rather matte), the solution needs to be changed frequently, it is quite aggressive (most often it is an acid). Work can be carried out only in overalls, the room must be equipped with a high-quality ventilation system.

In electrochemical polishing, parts are also immersed in a solution, but an electric current is passed through it. Since the surface is uneven, the oxide film is thicker in the micropits. The solution processes even parts of the surface with a thin layer of oxide faster. At the end of the process, the surface is perfectly smooth. Small time costs give an opportunity to increase productivity.

The disadvantage is the high consumption of electricity. If the surface is rough, mechanical grinding is required. It is necessary to carefully monitor the quality and temperature of the solution, the current density. Solutions are created from acids, so safety regulations must be observed. To reduce costs, it is desirable to pre-process the material by mechanical means.

At large enterprises, they try to automate and robotize polishing. This can be done using ultrasound, which increases productivity by 30 times and allows you not to purchase circles and pastes. Energy consumption is lower than when using a chemical or electrochemical method.

Metal polishing products

The technology of manual polishing of metal requires the purchase of equipment (drills, grinders) and various nozzles.

The main means for mechanically polishing metals are various pastes containing silicon, zirconium or titanium carbide, diamond chips, chromium oxide. Hard pastes must be diluted with oil. The costs are high, since the process consists of several stages, each of which requires different nozzles.

If a chemical or electrochemical method is used, large containers and acids are needed for the preparation of solutions, overalls. Nitric, hydrochloric, sulfuric, phosphoric acid, glycerin, benzyl alcohol are used. For a household, these are quite expensive purchases, so chemicals are used only in enterprises.

Metal polishing machines

All polishing machines are divided into 2 groups: with circles and tapes. Belts and circles consist of abrasives, the choice takes into account the requirements for surface roughness after processing. The equipment is semi-automatic or automatic. Automatic machines can become part of the lines used in mass production.

Any machine is equipped with a bed (platform) that does not change position during operation. An electric motor is mounted on the platform, which drives the shaft. You can work with grinding abrasives and circles. The sharpening angle is adjusted manually or automatically. Some designs are equipped with a water tank needed for cooling.

Available machines for processing raw materials (sheets of steel, aluminium, brass, profiles) and finished products:

• ship fittings;
• plumbing equipment;
• metal cornices and railings;
• door handles, parts of candlesticks;
• bicycle parts;
• tables and chairs;
• mufflers for motorcycles and cars.

The power of industrial models is 700-950 W, they are connected to a 220 V network. The rotational speed is 90-150 rpm. Adjustment is made depending on the characteristics of the material being processed and the format of the circle. At the first stages of processing, large circles are used, small ones are used for refinement. The package includes a cable and an extension cord. During operation, tools for measuring angles, stabilizers, pastes may be required.

The surfaces of metal products are finished not only to give them a beautiful appearance, but also to protect against rust, corrosion by acids, alkalis, etc. In one case, it turns out to be enough to file the product with a file, in the other, it is necessary to bring the surface to a shine by grinding and polishing , in the third - to cover with paints and varnishes, all this can be done by yourself at home.

Fig, 1. Finishing of metal surfaces: A - sanding; B - grinding with a file; B - grinding of round products; G - polishing with paste.

After processing metals with a file, more or less deep marks from the notch teeth always remain on them. To make the surface cleaner, smoother and even shiny, it is ground and polished.

GRINDING METAL

At home, metals are polished with emery skins after careful surface treatment with a personal file. To make it convenient to hold the skin, it is wrapped around a wooden block (Fig. 1, A) or a wide file; while holding the ends of the skin with the thumb and forefinger of both hands. Convex cylindrical surfaces can be sanded by wrapping sandpaper around them.

First, the surface is treated in different directions, with coarser coarse-grained skins, then with finer ones. The final grinding is carried out in one - longitudinal - direction with a sandpaper with the smallest grain. When grinding, the product must be fixed motionless.

POLISHING METAL

Mirror shine is given to metal products by polishing. Without preliminary grinding, only surfaces carefully processed with personal and velvet files can be polished. The file must be rubbed with chalk. The surface is first processed across the strokes present on it. When the strokes along and across are the same, the direction is changed by 90 ° and this is repeated several times. The surface treated in this way, as well as the grinding one, is polished with special polishing pastes.

The industry produces polishing pastes under the GOI brand. They consist of fine abrasive powders (chromium oxide, iron oxide, etc.), soft plastic substances composed of wax, stearin, kerosene and other materials. GOI pastes are coarse (dark, almost black), medium (dark green) and thin (light green). First, they are polished with a coarse paste, which makes the surface matte, then with a medium paste, and finally, with a fine paste, it is brought to a mirror finish. The paste is applied to a felt swab, cloth or linen cloth and rubbed on the polished surface.

Polishing pastes can be prepared by yourself. For polishing steel products, the following composition is recommended (in parts by weight):

Stearin - 32

Beeswax - 6

Technical fat - 5

Lead oxide - 3

Chromium oxide - 80

For polishing and polishing brass and nickel-plated surfaces, pastes of the following composition are used (in parts by weight):

Stearin - 5

Technical fat - 1

Chromium oxide - 14

The polished surface is wiped with a rag soaked in kerosene, and then dry with a clean cloth.

Well, I will continue in the same spirit, I will share my ordeals on polishing steel. What is written below is just my personal experience, if I'm wrong - correct me, I won't be offended. I made myself a katana not so long ago, although more precisely - a wheelbarrow with variations. The idea was to make an elongated katana and feel what medieval undersized Japanese felt. Those. approximately for them a katana, which for us Europeans is a wheelbarrow, and wakizashi for them, which is a katana for us. I think that if someone went in for sports, then he will understand how problematic is the mechanical transfer of martial arts, designed for undersized and strong Asians, to Europeans. In general, I did something with a blade length of 85cm, with a thickness at the thickest point of 8mm and a blade width of 29mm at the border with the handle. To facilitate the design, the butt had to be made very, very sharp, but in the end something turned out with a completely classic center of gravity 1/3 from the beginning of the blade and a weight of 1.05 kg (manual spring scales). After all the question arose about polishing; the main tool is a grinder with 8500 RPM. I tried almost all consumables, up to bronze end brushes. Of course, I used Velcro emery wheels. For me personally, it was important not to kill the edges on the katana, because. grinder cuts them too easily. Before the grinder, I used a new small and relatively soft grindstone, moistened with water so that a paste of abrasive was formed. With it, I finished the edges and refined the tip. Then I used the following grinding wheels: 80->120->180->400. The smaller the particle size of the circle, the faster it becomes unusable. 80, 120 - it took 2 laps; The 180s took three or four. The 400s are a different story. They took exactly 10 pieces. How to polish them? First, each circle must be walked on the not yet polished 400th surface. The circle wears out very quickly, a large abrasive flies off it, but the remaining particles give a real mirror. Therefore, when the circle begins to leave a mirror surface, it must be postponed "for later" and put a new one. When the entire surface is polished with the 400th, we put the old circles on the grinder and get a real mirror, albeit with individual scratches. The last stage is GOI paste. As for the name - the paste was developed by the State Optical Institute, and not by a Spanish artist of the new time (not a Goya or Goya paste); it is also not made by Jews for non-Jews (goyim; this is not "goyim pasta", although google knows such a request :). For her, I bought a felt circle, but such a circle is heavy and there is no point in putting it on the grinder - the vibration is so strong that either you will not feel well, or the grinder will fail. I put this circle on a drill, especially since it was with a speed controller. We rub the circle with GOI paste, if it has hardened (long-term storage), then we drip a few drops of kerosene onto the circle of paste and wait. until it is absorbed, after that the paste is easily rubbed into the circle. We drip a few drops of kerosene onto the polished surface, for example, using a glass tube (if any) or an eye dropper (sold in pharmacies). What kind of kerosene to take? Roughly speaking, there are two grades of kerosene on sale - one is light, the other is heavy. The first is a lighter-boiling fraction of oil, it smells more like gasoline and boils at a lower temperature. He won't suit us. The second is the heavier fraction, boiling at a higher temperature; it looks like old "aviation" kerosene - it has a characteristic smell. We need him, because. it evaporates much more difficult. we drip kerosene on the surface of the polished part and start polishing. A lot of GOI paste is not needed, kerosene sometimes needs to be added, but without fanaticism. With kerosene, the procedure is absolutely not dusty, but if someone does not like kerosene, get ready for its smell. In the end, we get a completely mirror surface, but do not forget to wipe it with a clean cloth, because. it is hidden under a layer of polishing products. The specularity is about the same as that of chrome surfaces, but small scratches are still present. Unlike chrome or nickel plating, the color is not white, but grey. To remove black deposits after polishing, I advise Kalosha gasoline - a cheap analogue of petroleum ether (yeah, who needs it for something, use this gasoline), which evaporates quickly. In the end, you can wash with soap and warm water, wipe dry and rub with alcohol, which dries perfectly.
By the way, does anyone know a household item with a hardness of 60 HRC? I checked the hardness of the tip - it scratches two types of glass i.e. more than 70 HRC (someone will say that I overheated it, but IMHO - just what you need for the tip), but the blade, of course, is not. But I don't know an object with a hardness of 60. I think it would be good for all lovers of bladed weapons making a table of household items in the hardness range of 45-75 HRC in increments of 5, so that one could immediately say that the hardness of the blade is such and such.

Stainless steel objects have firmly entered our lives. These are interior elements on the street and at home, various dishes at home and much more. Stainless steel is an alloy of iron and carbon with an admixture of special elements. Steel acquires high resistance to negative environmental factors thanks to these elements. But under the influence of various factors, even such a strong metal can lose its original appearance. How to polish to a mirror finish? If such a need arose, then you have two options:

• Contact a specialized company that provides this kind of service.
• Do it yourself at home.

Let's look at how metal is polished to a mirror finish with our own hands in different ways at home.

Polishing at home

At home, you can also get a shiny and smooth stainless steel surface. There are several ways to help us with this.

Preparing for polishing

First you need to properly clean the product. You can use dishwashing detergent for this:

1. Dilute detergent in water.
2. Clean the stainless steel surface with soapy water.
3. Rinse thoroughly and dry the product.

Polishing with olive oil

This method is suitable for polishing tarnished products. All you need is some olive oil and a soft rag or paper towel:

• Apply a little oil to the cloth and spread it so that the entire surface is covered with an oil film.
• Press the cloth firmly against the surface and polish the stainless steel product with smooth movements.

Important! Continue until you see a noticeable change in structure.

• Now you need to remove the remaining oil. For this, napkins or a dry towel are suitable. Wipe the surface until it is completely dry.

Flour polishing

How else can you polish metal at home? For these purposes, you can use flour, however, this method is more suitable for flat surfaces, for example, for pots, knives or sinks:

• Dust the entire surface with flour and spread it evenly over the metal.
• Polish with a soft cloth in a circular motion.

Important! For greater effect, you can use an old toothbrush.

• Shake off any remaining flour.

Chemical method

You can polish metal at home using a chemical method. To do this, you need to prepare a special liquid. There are several ways to do this:

• For such a solution, you will need 230 ml of sulfuric acid, 70 ml of hydrochloric acid, 40 ml of nitric acid. In 1 liter of solution, add 6 g of acid black dye, 10 g of wood glue and 6 g of sodium chloride. Bring this mixture to a temperature of 65-70 degrees and place your stainless steel items there for a period of 5 to 30 minutes.
• The solution is prepared in the following ratios: phosphoric acid 20-30%, hydrochloric acid - 3-4%, nitric acid - 4-5%, methyl orange - 1-1.5%. Put the product for 5-10 minutes at a temperature of 18-25 degrees.
• Per liter of the composition is 660 g of hydrochloric acid, 230 g of sulfuric acid and 25 g of orange acid dye. Heat the solution to a temperature of 70-75 degrees and put a stainless steel object there for 2-3 minutes.

Important! All these components are very aggressive, so it is necessary to provide full eye protection. hands, face and respiratory organs.

The stages of polishing with chemical solutions are as follows:

• Immerse the previously cleaned stainless steel item in a container with a chemical solution.

Important! Adhere to the strict dosage of the substances included in the solution to get the desired concentration.

• The liquid must be constantly stirred.
• After the expiration date, the product must be removed and the remnants of reagents washed off with clean water.
• Wipe the part with a polished cloth.

Under the influence of chemicals, all roughness will be eliminated and the product will acquire its original shine and radiant appearance.

Mechanical polishing methods

These polishing methods involve the use of tools and devices such as:

• polishing machine;
• Sander;
• electric grinder;
• grinder with lock.

Important! The method has a number of advantages. This is fast, efficient, you can change the frequency of rotation of circles and ribbons, use additional nozzles made of leather, fabric, wool and other materials.

The tool for polishing metal to a mirror finish with your own hands depends on the brand of stainless steel:

• Diamond paste showed itself best, but it has one significant drawback - a rather high price.
• If you don’t have one, then you can use GOI paste. It comes in four types, depending on the grain size.

Important! For manual grinding, you can use the same diamond paste or GOI paste. Its effectiveness depends on the quality of consumables.

This is done as follows:

• Apply a little product to the felt disc and drip a few drops of machine oil to dilute the paste.

Important! For metal, it is best to use a coarse-grained paste.

• Polish the surface in a circular motion, being careful not to rub too hard.
• Do this until you are satisfied with the result.

Important! How can I polish a knife to a mirror finish at home? Such smooth metal surfaces are polished with an ordinary file - a wooden beam covered with a cloth, on which a polishing paste is applied.

Stainless steel care

Polished stainless steel looks very nice. To keep it in this state, use special polishes. They are available as concentrates and liquid emulsions. The polish is applied immediately after the completion of the polishing process. Then periodically you need to apply polish to provide your stainless steel product with a pleasant look for a long time.

As you can see, everything is very simple, and it is very possible to give any metal object in your home a bright and neat appearance with your own hands. Choose a more convenient method for yourself and apply it as needed.

METAL CLEANING

1. CLEANING GOLD

a) Gold rings can be cleaned of iodine stains by immersing the ring for a quarter of an hour in a solution of 1 teaspoon of hyposulfite in a glass of water.

b) Cleaning matte gold. They take 80 bleaching powder, 70 bicarbonate salt and 20 table salt. Pouring a mixture of 3 mugs. distillation water, it is kept in sealed bottles. Blackened objects are placed in a cup and doused with pre-shaken liquid and left alone for a while. Sometimes the mixture is heated. After taking out the objects, they wipe them, rinse with alcohol and put them in sawdust to dry.

c) Gold objects are cleaned with a powder consisting of 16 chalk, 6 1/2 clay, 4 white lead, 1 1/2 magnesia and 1/2 bloodstone, or 80 iron oxide (kolkotar) and 30 ammonia.

2. SILVER CLEANING

a) Silver items can be cleaned by placing them for several minutes in a hot aqueous solution of cream of tartar (cremortartar) and then thoroughly rubbing with suede.

b) Silver spoons will always be clean and shiny if, immediately after use, they are washed in boiling water, to which a small amount of soda is added, and poured over with clean hot water, and then wiped dry with a soft towel. Once a week, spoons should be washed in soapy water with a small amount of ammonia. Thanks to this, even a completely tarnished spoon becomes shiny and looks just like new. Dark stains on silver spoons coming from eggs are removed by rubbing with ashes. Damp stains come off by washing in warm vinegar followed by rinsing in clean water and wiping dry.

c) It is known that both silver and silver-plated things tarnish relatively quickly in the air and take on a very ugly appearance. To eliminate such tarnishing, the following is recommended. remedy: a liquid solution of collodion is prepared and silver or silver-plated objects are lubricated with this solution with a thin and possibly even layer: the alcohol evaporates quickly and a thin, completely invisible film of collodium remains on the metal surface, which perfectly protects silver from tarnishing under the influence of air or gases contained in it . As shown by experiments carried out in foreign museums, silver coated with a thin layer of collodion retains its color, luster and polish for a long time. If necessary, this thin protective layer can be easily removed with hot water or even better with alcohol.

d) Silver items are first cleaned with water and soap, and their still warm surface is smeared with a solution of 1 sodium sulphate (hyposulfite) in 3 water, after which they are wiped with a rag.

3. CLEANING COPPER.

a) Objects made of polished copper are first wiped with a soft cloth soaked in kerosene, then cleaned with a woolen cloth with powdered chalk or Viennese lime. Heavily neglected copper objects are restored to their shine by wiping the object with a rag soaked in dilute hydrochloric acid. Then clean as above, or dissolve in 1 liter of water 30 g of oxalic acid, add 4 tablespoons of alcohol, 3 tablespoons of turpentine. After that, the liquid is shaken well and bottled for storage. When used, the object to be cleaned is lightly wiped with this liquid, and then wiped with a dry linen cloth: copper is quickly cleaned and becomes shiny. b) Mix 1 oxalic acid, 25 red iron oxide, 20 tripoli, 60 palm oil, 4 paraffin. It turns out a paste that perfectly cleans things made of copper and brass.

c) Red iron oxide (Caput mortuum), in the form of a delicate red powder for cleaning copper and brass objects, is obtained by heating iron sulphate until it dissolves into a white powder. This latter is then heated in a crucible, and a delicate red powder of iron oxide is obtained.

d) Mix a transparent powder of ferrous sulfate with the same solution of potassium oxalate. The resulting yellow precipitate is washed, dried and heated as above.

e) Mix 9 crude oleic acid with 1 kerosene, which can be dyed with alkannin or infusion with an alkane root.

f) You can refresh the surface of small copper products by boiling them for 30 minutes in a solution of soda ash (40 g / l).

g) Products made of copper and brass retain their luster if they are carefully rubbed with wax.

h) Darkened copper cleans raw potatoes well.

4. CLEANING OF THE GILDED BRONZE,

a) They take 5 glasses of water and dissolve alum in it until saturated, then boil the solution on fire until it is hot, rub the darkened place with a cloth until the stain comes off. b) Boil yellow peas, grind it until a thick dough is obtained and, while still warm, stick around a bronze thing with it. After a few hours, when the pea dough shrinks, the bronze is washed clean with boiling water and wiped dry with a clean rag. All rust and all stains will come off.

b) Bronze parts can be cleaned with a raw potato or a stiff hair brush dipped in hot vinegar. After that, the part must be wiped with a soft cloth,

5. CLEANING NICKEL.

Nickel objects to be cleaned are first moistened 2-3 times with a mixture of 50% alcohol (or vodka) and 1 sulfuric acid, then they are rinsed with water and washed with alcohol (or vodka), wiped with a thin linen cloth.

Nickel-plated surfaces of various objects can be cleaned with cigarette ashes, pouring it on a damp cloth.

Rust on nickel is removed as follows: smear the object with some kind of fat and leave it for several days, then wipe it thoroughly with ammonia. If the rust has penetrated deeply, instead of ammonia, you can take diluted hydrochloric acid, which, however, is left on the metal for no more than a minute. Then the object is washed with water and polished with chalk and crocus.

If the nickel layer is covered with a bluish coating, then it is washed with a mixture of alcohol and sulfuric acid in equal parts by volume. Rinsing lasts only a few seconds, then the item is washed with water and alcohol and wiped to dryness.

6. CLEANING ZINC.

Zinc things are cleaned perfectly with a solution of 1 hydrochloric acid in 2 water. This solution is rubbed with a brush over the object to be cleaned until the dirt is removed. Then, when the object is not yet dry, lightly oil it with wood oil and rub it with finely ground chalk with a cloth until a shine is obtained.

7. CLEANING STEEL.

A simple and good composition for this purpose is a mixture of paraffin and oil. 1 paraffin is added to a flask for 20 oil, thoroughly shaken until the paraffin is completely dissolved and, having previously wiped the object to be cleaned, cover it with the indicated mixture with a brush; then leave for 10-12 hours. in place, protecting from dust, after which the object is wiped with a dry woolen cloth. If a steel tool or some other object requires thorough cleaning, due to its significant rust, etc., then the following composition is used: a mixture of 5 turpentine and 25 stearin oil is prepared. This mixture is diluted with alcohol until a thick liquid is obtained, with which the object is covered, and when the alcohol evaporates, the metal surface is wiped with a mixture of 45 animal coal and 25 kolkotar (mummy) in powder.

8. CLEANING OF METAL PARTS OF MACHINES.

"Moniteur Industriel" indicates the next best practice in France. 10% of paraffin is added to one liter of kerosene and, having properly corked the vessel, set it aside for a day, shaking from time to time, after which the mixture is ready for use. Then, with the help of a cloth, all the metal parts of the machines to be cleaned are moistened with it. After moistening, leave in this form overnight (or even better for a day) and only the next day wipe dry with a clean cloth.

With this method of cleaning, rust, greasy tar dirt, etc., disappear, and the metal parts of the machines seem to be re-polished. There is no other way to clean them so well, not to mention the extreme cheapness of this method, which makes it quite suitable for cleaning all kinds of machines, tools, and in general products made of steel and polished iron.

POLISHING OF METALS ASSOCIATED WITH CHEMICAL CLEANING

1. POLISHING IRON.

Iron products to be polished are immersed for some time in a mixture of 1 sulfuric acid to 20 by volume of water, then the object is removed, rinsed thoroughly with water and dried in sawdust. After drying, it is immediately immersed for one or two seconds in nitric acid, after which it is rinsed again with water, dried again in sawdust and then thoroughly wiped. In this case, the surface of the object becomes shiny, like glass. According to "Cosmos"a, no other way can achieve such perfect polishing as the above.

2. POLISHING STEEL.

Steel products are polished with a leather mug coated with a mixture of 16 tin and 1 zinc. On the flat side of the mug, a crocus or bloodstone soaked in alcohol is applied and, after moderate drying, polished with agate.

3. POLISHED BRASS.

Equal parts water and ox bile boiled together make a good polish. The liquid, after cooling, is bottled and stored in them. When used, it is applied to brass and bronze objects with a brush or polished objects are dipped into it.

4. NICKEL POLISHING.

The mixture consists of 8 stearin, 32 lard, 2 stearin oil and 48 finely crushed Vienna lime. Objects are polished with this paste using a circle pasted over with cloth (according to Hildebrand).

5. POLISHING ALUMINUM.

a) Aluminum is immersed first in a strong solution of caustic potash or sodium, and then in a mixture of 2 nitric acid and 1 sulfuric acid. After that, it is placed in pure nitric acid and, finally, in vinegar diluted with water. After rinsing well in running water, dry in hot sawdust and polish with a polisher. Aluminum treated in this way acquires its natural pure white color.

b) 1 each of stearic acid and clay, 6 tripoli. If it is a matter of polishing smooth surfaces, then the paste is applied to a leather circle. After this treatment, the object is polished with another crocus using a leather mug, which makes the shine even more beautiful.

c) If polished by hand, then the most suitable is a mixture of vaseline and ceresin or a solution of borax in hot water, to which a few drops of ammonia are added.

6. POLISHES FOR METALS.

a) 90 g of finely sifted tripoli and 90 g of guinealithic acid are triturated with 450 g of liquid paraffin. After strong shaking, rub with a woolen cloth and polish with suede.

b) 60 Paris paint (pure iron oxide), 10 wax, 30 oleic acid and 2 rosin. From the addition of gasoline, iron oxide is mechanically distributed in the liquid, and large grains of polish sink to the bottom, and when drained, an elutriated mass is obtained that does not form scratches on the metal at all.

c) Equal parts of iron sulphate and common salt are ground well in a mortar and the mixture is heated in a flat crucible or other vessel to a red heat. Various chemical glassware at affordable prices can be ordered on the site moslabo.ru. In this case, vapors are formed, and the mass turns into a liquid. When the vapors no longer rise, the vessel is removed from the fire and allowed to cool. The resulting brown mass is washed with water to remove all undecomposed ferrous sulfate particles. The remainder is an excellent polishing powder.

7. MEANS FOR POLISHING ALUMINUM.

According to Morny, equal parts of olive oil and vodka are mixed in a bottle by shaking until the liquid resembles an emulsion. The polishing stone is dipped into the emulsion, and the aluminum is polished like silver, but without applying too much pressure. The black streaks that sometimes form from the polishing stone are not harmful, but they can be removed from time to time with a soft cloth.

8. POINTING A MAT ON ALUMINUM.

First, aluminum objects are launched for 20 seconds. in a hot 10% solution of caustic soda, which is previously saturated with common salt in a cold state. Then the objects are rinsed with water and rubbed with a brush, after which they are again immersed for 30 seconds in the above solution. After a second rinse and washing in hot water, the objects are dried in sawdust.

9. POWDER FOR MATCHING JEWELRY.

Consists of 40 g of saltpeter, 25 g of table salt and 35 g of alum. Mix into a homogeneous mass and heat in an enameled vessel, with constant stirring with a glass rod, until water vapor escapes. Then cool the mass by placing the vessel in cold water, turn into powder and store until use in well-closing glass vessels.

If the objects are to be only partially made matt, then the parts that are to remain shiny are covered before matting with a layer of the following mixture: 50 g of carbonic lime in powder, 5 g of sugar and 5 g of gum arabic are triturated with water into a slurry, which is applied with a brush to remaining shiny areas.

10. FINAL FINISHING OF MACHINE PRODUCTS.

To give locksmith products a beautiful look, they resort to various means, depending on the nature of the work. Small artistic forgings acquire a beautiful appearance if, at the end, they are supplied with an intense black color. But for such works, the paint is not applied by spreading, but the following operations are performed: a fire is lit in the furnace, corresponding in size to the size of the object being processed. The fire should not smoke (it is best to use coke for this). Then they lubricate the object with ordinary linseed oil and expose it to fire, but only for such a time until the oil evaporates and the rest of it burns to the iron. After cooling, rub the object firmly with a cloth lightly soaked in linseed oil.

The smoother the surface of the iron received during processing, the more beautiful the deep black color will look. This coloring is extremely strong and perfectly protects from atmospheric influences.

In order to pickle iron parts black, they must be clean, brilliantly straightened and polished. Then they are lubricated with liquid oil and sprinkled with wood ash, then they are held over hot coals until a run-down black color is obtained. After cooling, the objects are washed in water to which a few drops of sulfuric acid are added, and immediately wiped thoroughly with a coarse, clean cloth.

Rubbing with oil protects the product from exposure to air.

Fly marks on scales, panels and other parts are very difficult to remove with gasoline, alcohol and other solvents. At the same time, these stains disappear without a trace if the contaminated areas are wiped with a cloth or cotton wool moistened with saliva.

To make iron particularly soft, it is heated red-hot, quickly cooled in soap, heated again to red heat, and, after laying lime powder, is allowed to cool slowly. When processed in this way, the iron becomes very malleable and soft.

CLEANING THE GILDING.

Cleaning gilding, especially on wood, requires very careful handling. Previously, all dust must be swept away from the gilding, then the gilding is carefully wiped with a soft sponge, even better with a piece of cotton wool slightly moistened with wine alcohol or turpentine.

Instead of these liquids, good strong beer, a solution of the so-called Marseille soap, or a mixture of 10 parts of ammonia and 40 parts of soap alcohol are also used.

Egg whites are also considered a good cleaning agent for gilding, with which the object is carefully wiped with a piece of flannel.

You can use a mixture of proteins (2-3 eggs) with 18 g of sap water; With this liquid mixture, using a soft brush, lightly wipe the gilding, especially the most tarnished places.

Finally, pure wine vinegar can serve the same purpose, with which the gilding is covered with a soft brush, sponge, or piece of stalemate. After 5 minutes, the vinegar is carefully washed off with clean water, without wiping with anything.

For cleaning gilded bronze, in addition to ammonia diluted with water, the following method also gives good results: the gilding is wiped first of all with a brush moistened with water. Then cover with a soft brush with a mixture of 60 parts of water, 15 parts of nitric acid and 2 parts of alum, after which the liquid is allowed to dry without wiping.

CLEANING OF METAL PARTS OF MACHINES.

We give the best method, now practiced in France, for cleaning metal parts of various kinds of machines. To one liter of kerosene, 10% paraffin is added and, having clogged the vessel well, leave it for a day, shaking from time to time, after which the mixture is ready for use. Then, with the help of a cloth, all the metal parts of the machines to be cleaned are moistened with it. After moistening, leave in this form overnight (or even better for a day) and only the next day wipe dry with a clean cloth.

With this cleaning method, rust, oily resinous dirt, etc. are removed. and the metal parts of the machines seem to be re-polished. In no other way can they be so well cleaned, not to mention the extreme cheapness of the method itself, which makes it quite suitable for the indicated purpose with respect to all kinds of machines, tools, and in general products made of steel and polished iron.

Definition of the concept of "polishing" and its types

Polishing is a type of metal treatment that restores the shine to the metal surface. At the present stage, the following grinding methods are distinguished:

What tools and machines are used? Mechanical methods involve the use of the following tools and devices:

• polishing machine;
• Grinder;
• electric grinder;
• drills with clamps.

This finishing method has a number of advantages. Firstly, it allows you to change the frequency of rotation of circles and tapes, which has a positive effect on the quality of processing a metal plane; secondly, additional nozzles made of fabric, leather, wool, etc. can be installed on the polishing machine.

Special grinder - angle grinder

Manual grinding differs from automated grinding in that its effectiveness depends on the quality of polishing consumables. In manual finishing, diamond paste and additives based on chromium or iron oxide are used. Smooth metal surfaces are polished with an ordinary file - a wooden block covered with a cloth, on which a polishing paste is applied.

Metal polishing with a special tool

Combined processing methods

Metal polishing can be carried out by combined methods, in the case of an unprepared and rough surface with a rough relief. In this case, a long-term electrolytic-plasma finishing is prescribed, which consists of removing a significant layer of metal.

This processing method is used in extreme cases when a quick restoration of the gloss of a metal product is required. Among the shortcomings of the technology, one should highlight the high energy intensity, especially at the initial stage of processing, when 100% more energy is used than usual.

The electrolytic-plasma polishing machine processes the part in two stages. On the first one, the surface is degreased, and on the second, the grinding itself, which, in turn, also consists of two cycles: cutting the rough layer and grinding the metal. Grease removal is mandatory, since the viscous surface leads to oxidation of the metal and a deterioration in the quality of its finish.

Classification of metal polishing pastes

You can bring the metal surface to a mirror state with your own hands without using machines, just pay attention to special toolsdivided into the following groups:

• Water. The substance does not contain fat and does its job perfectly;
• Organic products - contain paraffin and a variety of oils. They are diluted with various oils and fatty acids;
• Diamond paste is a revolutionary solution that allows you to instantly achieve a shine on any metal surface.

Let us dwell in more detail on the last version of grinding. Diamond paste is so effective that it completely replaces the polishing machine. Diamond Substance is available in two types: ASN and ACM (expensive).

Diamond paste has the following advantages:

• Accuracy. Synthetic diamonds allow you to polish any metal product to a shine as accurately as possible;
• Wide range of grain sizes. More than 12 types of grit can be found on the market today;
• Simple operation allows you to carry out cleaning procedures with your own hands without the use of a special tool;
• Diamond paste requires a minimal tool: a rag, water and rubber gloves.

The main disadvantage of this cleaning agent is its high price. On average, diamond paste on the consumables market costs more than 500 rubles per 35 grams of the substance.

Working principle of diamond paste

Diamond paste acts on a metal product mechanically and chemically, forming dispersed films. The composition of the cleaning agent includes active substances that promote the flow of adsorbing processes, which facilitates the grinding of the material.

Diamond paste is applied to various types of fabrics (felt, microfiber or jeans), paper, rubber, plastic and other types of non-metallic materials. It should be noted that diamond paste can also be applied to polishing wheels to improve the efficiency of metal surface treatment. In this way, you can achieve a mirror effect. Circles made of felt, felt or leather are installed on the polishing machine.

Description of the polishing process

To grind a metal surface, you will need: lapping laps and several tubes of diamond mixture with different grain sizes. Diamond paste is evenly distributed over the working surface of a rag or other material. Experts have noticed an interesting pattern that improves the quality of metal processing.

It turns out that castor or olive oil must be added to the polishing agent. The ideal ratio is considered to be a mixture consisting of 40% diamond dust and 60% oil. After dilution, the mixture is immediately applied to the metal surface.

Experts recommend starting work only with large grains, gradually moving to abrasive products. During processing, make sure that no extra elements get into the mixture - dust, sawdust, hair or pieces of rags. The presence of third-party objects greatly impairs polishing to a shine. It is also recommended to wash your hands after changing from one grit to another.

Types of diamond dust

On the modern market, you can find tools not only for polishing metal, but also other materials, such as wood, glass, stone, etc. You can classify them by color, for example:

Huge range of diamond paste

• Yellow packaging indicates that the substance is intended for grinding ceramic materials and glass products. It should be noted that this dust can also be used for metal finishing;
• Blue packaging. This type of product is used for glass finishing. The grinding tool has a fairly wide selection of abrasive elements - from 60 to 10 levels;
• The red packaging is suitable exclusively for the treatment of metal surfaces.

As for the packaging itself, diamond paste is sold in compact plastic jars, 35–45 grams in volume. The average cost of a jar depends on the size and quality of abrasive materials. The finer and better the polishing material, the cheaper the paste is. The average price is 450-600 rubles.

Paste GOI

Chrome paste GOI is a universal tool for polishing metal and non-metal surfaces. Although it was invented in the early 1930s, it is used to polish metals even today.

Polishing paste GOI

The GOI tool comes in different grain sizes (classified by the size of the abrasive materials). There are three types of grit: fine, medium, and coarse. Fine dust is used for polishing soft and non-ferrous metals, coarse grain - for rough finishing of ferrous metals and steel.

Features of use. Initially, the polishing agent has a solid structure, which can be diluted with a few drops of machine oil. If you need to polish an uneven metal surface with bends, then it is recommended to apply the paste in a diluted form to a rag.

The second polishing method is designed for smooth metal surfaces. Its peculiarity lies in the fact that a small amount of abrasive material is applied to a wooden block. Then it is recommended to make methodical movements back and forth on the surface to be treated.

With force, the rolled bundle retains its shape. Prepared 5 nozzles marked P400, P500, P800, P1000, P1200. There are large transverse scratches. Shaft torque is highly dependent on speed.

Up to 12,000 rpm, the speed drops when pressed, and above 20,000 rpm, the skin wears out quickly. Sand perpendicular to the scratches until they disappear. Such a nozzle is quickly updated and provides the necessary pressure on the surface.

A lot of things for the home master in this Chinese store.

The worn and greasy part is cut off. The direction of grinding periodically changes to perpendicular. So the material is removed more efficiently and chaotic scratches are better removed. Increasing the paper number. In the process of grinding, the paper wears out, its aggressiveness decreases, and a large abrasive crumbles. Therefore, less pressure should be applied to the new paper so as not to get deep scratches. Coarse paste for fine grinding. 320 is all that was indicated on the package.

Before changing to a thinner paste, the polishing area must be cleaned of its residues. Another no name paste. The composition contains a dye. One can only guess about the type of abrasive. It is not necessary to do this, the paste is applied only to the nozzle. Noticeable quick sanding. Sanding is better.

Metal polishing is more than sanding with fine abrasives. There are also chemical processes (dissolution of oxide films by substances that are part of the pastes) and thermal (thermal softening of the material and smearing it over the metal). Before polishing, the surface must be cleaned of scratches, gradually reducing the size of the abrasive. Before moving on to finer sandpaper, make sure that all scratches are removed. Depending on the depth of the scratches, the number of sandpaper is selected, from which grinding will begin. If there is a medium paste GOI No. 3, sandpaper with a number greater than P1200 can be omitted. their grain size is comparable, and the sandpaper itself with a small grain size is quickly salted.

For polishing steel, the optimum nozzle pressure is 1-2 kg/cm^2 and peripheral speed is 30-35 m/s. Peripheral speed formula. V=(3.14* D* n)/60 (m/s); D-diameter of the nozzle (m); n-speed (rpm). In the case shown, V=(3.14*0.01*15000)/60=7.8 m/s. This is 4 times less than recommended. Those. it is possible to increase the diameter up to 4 cm without loss of quality. At the same time, it will quickly crumble from cotton wool, but it will withstand leather or cotton threads.

Polishing at a higher speed and pressure than recommended reduces the quality of the surface, but increases the amount of metal removed, so this can be used at the initial stage of polishing. To obtain a better polishing, the speed and pressure are reduced to values ​​lower than those recommended.

During the polishing process, the binders included in the paste melt and act as a lubricant in the process of cutting the material with an abrasive, and also remove heat from the surface. At the same time, the polishing nozzle itself heats up and the binder begins to penetrate deep into it, leaving the abrasive grains without lubrication and heat sink. After that, the grains, having lost the binder, fall off and leave scratches on the treated metal. For the same reason, the paste should not be applied to metal. The nozzle passing through the metal cannot capture all the material, and the captured abrasive grains are not held well enough, moreover, the grains themselves are not evenly distributed over it. Too much pasta isn't good either. It simply slides over the binder layer between the metal and the nozzle, and the abrasive grains float in the layer without coming into close contact with the surfaces.

Since the binder must melt for normal operation of the paste, such pastes will work only in a certain temperature range, when the binder has already melted, but is still thick enough to hold the abrasive grains on the nozzle. For most pastes, the range starts at 70 degrees Celsius. And it is for this reason that polishing by hand is extremely inefficient. For normal operation, this must be melted, add any liquid oil and mix. Conventional softening solvents are not suitable. quickly evaporate and the product thickens.

Source: youtube.be/lMjLMd1dY8Q

Matting and polishing aluminum

We have been working with manufacturers of metal products for a long time, and we know that the appearance of the product is very important. When it comes to technical products, everyone here is already accustomed to polishing, satin or matting the surface.
But sometimes our partners have to work with decor items. And sometimes the customer wants the surface to look unusual.
One of the options for such an unusual solution, we offer you below.
The so-called "muddy polishing".
This time we processed flat aluminum parts.
For aluminum, one of the most convenient processing methods is an orbital sander. It allows you to get the most even and monotonous surface on such a soft and capricious metal.


For pre-grinding aluminum, we used our matting technology, only changed the number and graininess of the circles used:
Grinding wheels Velcro AO (aluminum oxide) d125, grit P180- the first step by which we remove all defects and level the surface.
Grinding wheels Velcro AO (aluminum oxide) d125, grit P220- reduction of roughness.
Grinding wheels Velcro AO (aluminum oxide) d125, grit P400- reduction of roughness.
Grinding wheels Velcro AO (aluminum oxide) d125, grit P600- final grinding.


After processing the OShM, the surface already becomes uniform and beautiful. But this time the task was to get something new.
It was decided to polish our workpiece from above using the same eccentric machine.
If you polish the surface with a conventional polishing angle grinder, it will be very difficult to achieve an ideal result. Such a process will take much more time.


Surface after P600.
It is better to use liquid polishing pastes for polishing with OSM, since hard paste is difficult to apply to the polishing wheel during orbital movement.
The polisher itself should also be used softer.
We recommend:
Polishing wheel Finesse-it d125 soft felt
Liquid polishing pastes G-Polish Pink
We apply the paste on the circle and proceed to polishing.


After polishing, the surface looks dirty and the gloss is almost invisible. This is because there is a lot of paste left on its surface.


To remove the remaining paste, use Viennese lime with a microfiber cloth:
Vienna lime
Cleaning cloth


Now the surface looks great.


Aluminum is a fairly soft metal. Therefore, to prevent aluminum from oxidizing and tarnishing, we varnished the product.
There are different ways to finish such a surface - you can grind to a finer grain or polish in two steps to get more gloss.
But that's a completely different story.

Metal polishing will help to significantly improve the aesthetic appearance of the product. If it is not possible to turn to professionals, then you can polish yourself, at home, the main thing is to follow the technological process.

The process of polishing to a mirror at home

There are several proven methods for polishing metal at home. One of them is chemical (without the use of mechanisms). It does not require much effort, the main thing is that it follows the safety requirements. Metal polishing at home by a chemical method occurs in the following order:

1. Sulfuric acid is diluted with water in a ratio of 1:20. The volume of the resulting mixture should be sufficient to completely cover the thing to be polished;
2. We lower the polished object into the resulting solution for several minutes, and, having taken it out, wash it in running water. Next, place in a container filled with sawdust;
3. We lower the metal object dried in sawdust for 2-3 seconds into nitric acid, after which we again thoroughly rinse;
4. After another drying in sawdust, carefully wipe the metal.

After such simple procedures, the metal object will look like new. A smooth and shiny surface will be perceived by the eye as a mirror.

TIP: Before lowering a metal thing into acid, you need to remove all elements made of other materials from it. Other materials can be adversely affected by acid and destroyed.

One of the most popular types of home metal polishing is processing with GOI paste. This paste was created in the last century and has been successfully used to this day. Initially, it has a solid shape and comes in varying degrees of granularity. For better application, it is recommended to dilute it with a few drops of machine oil.

For manual polishing of soft metals, it is recommended to use a soft flannel cloth coated with a fine-grained paste. Ferrous metal can be polished with a piece of canvas or denim with a coarse paste. For faster results, instead of a rag, you can use a felt circle attached to a hand drill, or a small wooden block.

Required equipment and chemicals

To get a good result at home, you will have to spend a little money and stock up on some chemicals, fixtures and mechanisms. Depending on the method by which the metal will be polished to a mirror finish with your own hands, you will need several items from this list:

• Sulphuric acid;
• Nitric acid;
• Water;
• Sawdust;
• Paste GOI;
• Felt circle;
• Drill;
• Wooden block;
• Textile.

polishing process

Polishing metal to a mirror finish at home is a rather lengthy process, the main thing here is not speed. If the process (mechanical) is carried out without the use of electrical assistants (after all, some metal objects can be “wiped”), then each square centimeter of the product should be carefully and for quite a long time, with extreme caution.

Advice! For items with recesses, you can use an old toothbrush smeared with GOI paste. It is convenient for her to get to hard-to-reach places.

Safety

When using a chemical polishing method, be sure to use special gloves, respiratory protection, special dishes that do not react with acid. Polishing metal to a mirror finish with a grinder or drill should be carried out using eye protection. And most importantly, it is necessary to strictly adhere to the technological process. It is necessary to always have a first-aid kit on hand, with which you can provide first aid before the arrival of the ambulance, although it is advisable to prevent such cases.

Result

Grinding and polishing of metal at home, carried out in compliance with all technical requirements, is able to completely restore the appearance of a metal object. With minimal financial costs and a certain skill, you can achieve high results.

If you need to compare your work with the ideal result, you can always watch a video on the Internet - “Grinding and polishing metal at home”, where you can find lessons on various polishing methods. They tell in detail about all the nuances of polishing metals at home.