Even people far from plumbing and other work have heard about GOI paste. It seems like you can use it to polish and grind metal, plastic and even glass. Let's figure out what can be done with it, how to use it correctly, consider the gradation of paste grain size and approximate prices in stores.
It was invented in the thirties and to this day is one of the best pastes for polishing metal products. I won’t list the ingredients for you, because all this can be found on the internet, but I’ll just say that it’s made on the basis of chromium. Among other things, it is used for fine polishing after whetstones.
Sold in different containers, from small 30 gram jars to massive cylinders weighing a kilogram or more.
But what many people don’t know is that pasta comes in different grain sizes. For many, it's just a green paste used to polish metal. However, the polishing process requires that the abrasive (which it is) be of different “coarseness”, because it is used not only at home. Coarse grit may scratch the surface, while fine grit will not be able to remove deep scratches.
Therefore, pasta comes in 4 grains:
- No. 1 very fine, used for polishing and giving the perfect shine
- No. 2 is not much different from number one
- No. 3 medium grit removes all unnecessary material on the metal, leaving the metal with a matte finish that can be brought to a perfect mirror shine using finer grits.
- No. 4 is the largest paste, it can even remove shallow scratches on metal.
General questions are well reflected in the video:
How to use GOI paste.
There are a huge number of different instructions on the Internet, which reflect all sorts of nuances such as movements when polishing, what rags to use, etc. I will indicate the main points that are worth paying attention to.
- How to dilute GOI paste. As you know and have seen, paste is a rather dense and hard mass. How to apply it, for example, on a regular rag to polish a spinner or something else? Therefore, it needs to be liquefied; for this, ordinary machine oil is used. Break off a small piece, add a few drops of oil, stir until smooth. Now you can apply GOI to a cloth and polish whatever you wanted there.
- The second application method is suitable for grinding and straightening knives or cutters. Take a wooden block/board and rub it with paste until there is enough abrasive on the wood to work the metal. Then simply straighten the knives by moving the knife back and forth along the block, maintaining a certain angle of inclination.
- When polishing on emery, felt wheels are used; apply the paste to them as well, diluting it a little with oil.
- Now about materials for polishing - about rags. If you are polishing a plastic surface, use the softest cloth - cotton or flannel. To polish metal, you can use a coarser fabric - jeans, tarpaulin, or the same felt circle. Think about old felt boots - an excellent material for polishing metal using GOI paste.
In terms of cost, small jars cost 20-30 rubles, a kilogram bar costs 200 rubles.
– this is a special abrasive material in the form of a dense granular paste intended for grinding and final finishing of metal surfaces. GOI paste has been used in metalworking, technology, arts and crafts and other fields of activity. The abbreviation GOI means State Optical Institute, the enterprise where this material was developed.
Types and composition of GOI paste
The basis of GOI paste is chromium oxide with the addition of stearin, fat, silica gel and kerosene. The more chromium oxide in the composition, the more granular the material is - the larger the grain size and the rougher the processing. Therefore, pay attention to the composition of the GOI paste you have chosen - the possibility of solving a particular problem depends on this. The coarsest has 81 parts of chromium oxide, the medium has 76, the finest has 74 and, among other things, contains bicarbonate of soda.
In general, the grain size of the paste is determined by its designation - fine, medium and coarse, or by number - from 1 to 4:
- No. 1 - for final polishing and adding shine.
- No. 2 is almost identical to No. 1.
- No. 3 - medium grain, gives the metal a matte shine, removes small irregularities.
- No. 4 – the largest grains, a high abrasive sufficient to remove small scratches. Not suitable for precision grinding.
Features of using GOI paste
A frequent question from users of GOI paste is how to use it in this or that case. The answer to this depends on the specifics of the problem being solved. Let's look at the basic rules of polishing.
So, the answer to the question: how to polish metal with GOI paste, let's start with the main rule - you cannot apply the paste to the surface itself. It is applied to a cloth or, if we are talking about grinding knives, to a wooden block. Before use, the paste must be rubbed on an unusable piece of metal to get rid of large pieces that can damage the surface. This is equally important for successful application.
Let us draw your attention to the following important tips:
- Sufficient density and hardness of the paste requires it to be liquefied before use. To do this, you can use spindle oil, stirring it with the broken fragment until a homogeneous consistency. After this, you can apply it to a rag.
- To polish knives, the paste is applied to a wooden block or board. Then you can move the knife back and forth at the angle required for editing.
- To work on a grinding machine, the paste is applied to a felt wheel. To do this, you also need to dilute the paste with machine oil.
An important role when polishing is played by the choice of rags - soft or harder. To polish plastic, you need the softest flannel or cotton cloth. Fine polishing of metal can be done with denim, canvas or felt. Old felt boots are also suitable for these purposes.
In general, GOI paste is an important tool in metalworking for precision surface processing, high-quality grinding at minimal cost and without the use of special equipment.
The modern chemical industry offers a wide selection of specialized abrasive compounds for polishing and grinding any materials. However, all modern products are united by a narrow specialization (by type of surface being treated and by grain size), as well as the serious cost of branded polishes. As a universal analogue that adequately copes with the finishing of metal, plastic or glass, we can name the long-known GOI paste.
Composition and properties of GOI paste
The abrasive paste produced by the State Optical Institute was developed in the 30s of the last century as a means for high-precision finishing of the surfaces of metal, ceramic and glass parts. The original composition of the paste contained chromium oxide powder, which provided a memorable dark green tint to the composition.
Currently, chromium oxide is prohibited for use as it is a toxic compound. Therefore, modern GOI pastes are made on the basis of aluminum oxide and are red or white in color.
The red paste provides intense polishing, while the white paste is designed to create a smooth, glossy surface.
The paste also contains plasticizing and binding substances, such as stearin, silica gel and kerosene, and auxiliary additives.
Depending on the size of the abrasive fraction, GOI paste is divided into the following types:
- No. 4 is intended for primary processing (removable layer from 20 to 40 microns);
- No. 3 to form a matte surface without marks from abrasive particles;
- No. 2 and No. 1 for final fine polishing (removable layer no more than 0.1 microns).
According to the release form, GOI paste comes in bars, tubes and containers, and there are also polishing wheels for grinders impregnated with the composition.
Car enthusiasts and service stations successfully use GOI paste for grinding and polishing car glass (especially windshield glass), mirrors, as well as headlights and other lighting fixtures.
Headlights
Car headlights are an important element of traffic safety. They must provide the intensity and dispersion of the light flux sufficient for confident movement at night and in conditions of poor visibility. The vast majority of traffic accidents at night occur due to insufficient lighting or malfunctioning lighting devices.
Most modern cars are equipped with plastic headlights, but there are headlights and fog lights with glass lenses.
When using a car for a long time, the glass of the headlights becomes cloudy under the influence of the external environment. Solid dust particles and small stones leave scratches and microchips on the outer surface of the headlights. Plastic headlights also often become cloudy from exposure to tar, motor oil and aggressive auto chemicals. You can restore the transparency of headlights using GOI paste. To assess damage to the outer surface of the headlights, they should be thoroughly cleaned of dirt and dust using specialized detergents. Contaminant particles that are not removed from the headlight glass will lead to additional scratches during subsequent grinding.
Polishing headlights with GOI paste is done manually or using a felt attachment on a drill. To achieve the desired effect, you need to treat the damaged surface for at least 3-4 minutes. Periodically, you should clean the headlight from dust and excess paste using a dry cotton cloth, and evaluate the result achieved. Grinding is carried out until the headlight glass becomes absolutely smooth.
If the transparency of the headlight could not be restored by grinding the outside, it means that the defect is on its inner surface. This problem is typical for plastic lighting fixtures: Under the influence of high temperatures from halogen or xenon lamps, the inside of the headlight becomes cloudy. To restore transparency, it is necessary to disassemble the headlight and polish the inside of the lens. Glass headlights, as a rule, do not need to be polished from the inside; it is enough to wash the light-transmitting surface well with a glass cleaner.
In a similar way, using GOI paste, you can restore the appearance of faded or worn out rear lights.
Attention! During manufacturing, a protective coating is applied to the surface of plastic headlights, which is removed during the grinding process. Therefore, after polishing with GOI paste, it is necessary to re-coat the treated area with a special varnish in several layers. The protective film dries after at least 24 hours.
The sequence of steps for polishing headlights with your own hands can be seen in the following video:
Glass
When the car moves, grains of dust and debris carried by the oncoming air flow intensively damage the outer surface of the interior glazing with sharp edges. Additional damage to the windshield in the form of chips and cracks is caused by small stones flying out from under the wheels of oncoming traffic, as well as grains of sand that fall on the windshield wiper blades. When the window lifters are repeatedly activated, the door windows are scratched by solid dust particles deposited on the inside of the seals - velvet. Excessive efforts when cleaning glass from adhering ice and snow with a hard scraper or wiping with a dry, rough cloth also add mechanical damage.
As a result, the glass becomes dull, cracks, scratches and abrasions impair visibility, and at night they distort the headlights of oncoming cars, blinding the driver.
Shallow glass damage (up to 300 microns), microcracks, chips and local abrasions from wipers can be eliminated by grinding and polishing the glass using GOI paste.
In the presence of deep scratches, extended cracks and chips, grinding can lead to loss of transparency and curvature of the glass surface. In this case, it is advisable to replace the glass with a new one.
Before polishing car windows with GOI paste, they must be thoroughly washed and dried. It is recommended to highlight defective areas with a marker on the inside of the glass. Adjacent parts of the roof, pillars and hood must be protected from accidental damage with masking tape or other material. When polishing (especially using power tools), be careful not to damage the glass.
To polish the windshield, you should use only GOI finishing paste with a minimum size of abrasive particles (No. 1).
How to dilute
Before use, GOI polishing paste requires pre-softening. In its initial state, the paste can be quite dry, which will make it difficult to apply to a polishing cloth, and hard lumps will lead to the formation of unnecessary scratches on the glass during processing.
The list of liquids used to soften the material is quite extensive: from distilled water, industrial and motor oils to white spirit and purified gasoline for lighters.
It is not recommended to dissolve GOI paste with gasoline or white spirit. due to their flammability, and then it is difficult to neutralize the specific pungent odor of these liquids. The following method is more practical:
- Apply a small amount of motor oil to a block of GOI solid paste using a syringe or pipette;
- the liquid is rubbed into the block using flannel or cotton cloth until the paste has a consistency similar to plasticine;
- With the resulting plastic mass, you can polish defective areas of glass or headlights without the risk of damage.
For greater homogeneity, the mixture of GOI paste with motor oil can be heated before use (for example, in the microwave) and mixed thoroughly.
Advice! Prepare the polishing mixture in batches. Over time, the liquid evaporates and the paste becomes solid again.
The glass or plastic surface to be treated must also be moistened with water and lubricated with industrial or motor oil. If you apply GOI paste on dry glass, there is a high probability that the outer layer will become dull.
How to use
The principle of processing with GOI paste is that the small particles contained in the paste remove a thin layer of glass along with microcracks and scratches.
The pre-prepared paste should be applied to a cloth or polishing wheel and lightly wiped on a hard surface to remove excess and solid particles. After this, the defect areas are ground first with reciprocating movements with partial overlap of the strips, and then in a tapering spiral from the edge to the center of the damage.
Important! The paste should be applied only to the working surface of the instrument, and not to the glass itself.
Periodically you should wipe the element being treated with a damp cloth and monitor the condition of the polished surface.
Polishing with GOI paste using a grinder should be performed at medium speed (no more than 1000 revolutions), with smooth movements without stopping the working tool in one place. The grinding wheel should be positioned at an angle of no more than 5 degrees and have the maximum possible contact area with the workpiece. Should be constantly check the degree of heating of the polished surface(especially for plastic headlights) and, if necessary, stop grinding until the part has cooled.
Upon completion of polishing, the remaining paste and abrasive dust should be rinsed off with plenty of water, and then wipe the glass dry with a microfiber cloth.
To maintain the effect, it is recommended to repeat the polishing procedure approximately once every 1.5-2 years, depending on the operating conditions of the machine.
The State Optical Institute was founded in 1918. The focus of the organization is the connection between science and industry. GOI invented something that would be useful and have practical application. One of the products is a paste based on chromium oxide. They named the mixture after the name of the institute, or rather, its abbreviation. GOI is still used today.
What is GOI paste?
Paste GOI– composition for grinding and polishing metals and their alloys. Processing occurs due to abrasive particles. The color of the pastes is green. The saturation of the paint may vary depending on the type of composition.
There are 3 types of GOI - coarse, medium and fine. The names depend on the size of the abrasive granules. The color of the mixtures depends on the concentration of chromium oxide. This substance is green.
The composition is produced in the form of bars. To polish, you need to rub them on special wheels or cloth. For convenience, ready-made felt discs impregnated with GOI are also made. The system was developed back in the 30s of the last century.
Composition and use of GOI paste
In addition to chromium oxide, the paste contains organic fats and other binders. Kerosene, silica gel, steorin are used as solvents.
Paste GOI, buy which is available in different consistencies and is used for different purposes. Rough compounds are used to remove the maximum amount of metal from the surface.
At the same time, it becomes matte. Medium-fine pastes provide a clean surface. For a shiny, glossy surface, a thin paste GOI. Price She is most interested in jewelers who polish jewelry, that is, give it a mirror shine.
However, experts do not recommend constantly resorting to cleaning GOI jewelry. Each procedure removes the top layer of metal. As a result, it becomes thinner. It is better to entrust the cleaning after purchase to a specialist.
Even thermally hardened alloys can be polished and ground if in the hands of a master paste GOI. How to use Several specialized brochures and a lot of Internet resources tell the story.
First, the mixture is applied to woolen fabric. It is contraindicated to apply ointment to metal. In this case, the procedure will cause deep scratches on the surface being treated.
The paste is distributed evenly over the material, leaving no lumps. Gasoline impregnation of the fabric helps the GOI lie in an even layer. A spindle is dripped onto the metal. This is what industrial oil is called.
To achieve maximum effect, it is also added during the polishing process. This is not an every-minute task if done manually. In industrial conditions, polishing wheels are used to speed up the process.
How to polish with GOI paste fishermen are interested. With the help of the composition, they bring the spinners to shine. During use, they get scratched, lose their shine, and without it, the fish do not perceive the bait.
Buy GOI paste in Moscow and not only hunters strive. They polish gun barrels with the mixture. They must be perfectly smooth, otherwise the gunpowder or bullet may get caught on the roughness. At best, the trajectory of the projectile will change, at worst, the barrel will rupture. By the way, it is sometimes polished to increase its diameter.
Polishing with GOI paste used for car headlights. Chips and scratches on them are removed with compounds with medium-sized abrasive particles. The paste is ideal for cloudy or darkened glasses, but without significant damage to them. In this case, there is no need to go to the service center.
GOI is suitable for any plexiglass, from which, among other things, commercial equipment and elements of office furniture are made. The material is also used for souvenirs and even costume jewelry.
Price of GOI paste
Buy GOI paste in St. Petersburg(abbreviation for St. Petersburg) is available in Mikronika stores. They ask for about 300 rubles per kilogram. In a small package the composition costs 30, 50 rubles. Pasta is also sold in packs of 800 and 1000 plates each.
In Moscow, the mixture is sold in Voentorg chain stores. The retail outlets are called “Tylovik”. Packaging of the composition from 30 to 1000 grams. The cost, accordingly, is from 20 rubles to 360. Pasta GOI Moscow presented in all 3 types, from fine to coarse.
To the question: - “ GOI paste, where to buy“, the answer is in car stores, hardware stores, points selling weapons, in jewelry workshops.
Regarding geography, the opportunity to purchase the composition is available in all cities of the country. Thus, in Ussuriysk the Solnyshko company sells 25 grams of the product for 20 rubles. In Volgograd, GOI is located in Volzhskaya Production Company LLC.
Packaged in kilograms, price – 220 rubles. Intelross from Kirov sells a 100-gram block for 100 rubles. In Novosibirsk, Setka Wholesale LLC sells pasta. They ask for 678 rubles per kilo. GOI is also sold abroad. However, outside of Russia the paste has a different name. You should look for the “Green rouge compound”.
The modern chemical market offers motorists a wide range of abrasives for grinding and polishing. Many compounds have a very narrow specialization, that is, they are intended to treat only a certain type of surface, and branded polishes are also very expensive. Today we will tell you about GOI paste - a universal product that can be used for polishing various materials.
1 Composition and technical characteristics of GOI paste
The GOI (State Optical Institute) abrasive paste was developed back in the 30s of the 20th century and has since been used for high-precision finishing of the surfaces of glass, ceramic and metal products. In those years, the paste included chromium oxide powder, which provided it with a recognizable dark green tint.
Today, chromium oxide is not used in the production of abrasives, as it is recognized as overly toxic. Instead, aluminum oxide is used to make GOI paste, which gives the composition a white or red color. It is better to use red paste for polishing, and white paste to create the smoothest glossy surfaces.
GOI paste is usually spoken of as a universal product that can be used for polishing various materials. In addition to aluminum oxide, modern GOI paste for polishing windshields includes special binders and plasticizing substances, in particular, stearin, kerosene and silica gel. Depending on the size of the abrasive fraction, there are several types of polishing paste:
- No. 4. Designed for initial surface treatment. Capable of removing a layer with a thickness of 20 to 40 microns.
- No. 3. Used to create matte surfaces without traces of abrasive particles.
- No. 2 and No. 1. Designed for fine, final polishing of surfaces. Provides removal of a layer less than 0.1 microns thick.
On the market, GOI paste can be found in different packaging: bars, tubes, containers. Special polishing wheels made from paste are also produced for grinding machines. Car enthusiasts and specialized service centers use this composition for polishing and grinding car mirrors, glass, headlights and other lighting devices.
2 Rules for using paste for polishing car headlights
Headlights are one of the important elements of the car, affecting the safety of using the vehicle at night. They must create an intense luminous flux, powerful enough to ensure good visibility. A significant portion of road accidents that occur at night occur due to poor lighting or problems with lighting devices.
Modern cars are usually equipped with headlights made of plastic, but there are fog lights and other light sources made of glass.
During the operation of the car, the glass of its headlights becomes cloudy due to constant exposure to the environment. Microchips, scratches and cracks appear on lighting devices due to small stones and dust getting into them. Plastic headlights often become cloudy due to exposure to motor oil, automotive chemicals and tar. To restore the original transparency and functionality of headlights, you can use GOI paste.
Periodically, you need to clean the headlight from excess abrasive substances and dust with a dry cotton cloth in order to evaluate the results of polishing. Before starting polishing, it is necessary to assess the extent of damage to the lighting fixtures. To do this, the surface of plastic or glass headlights is thoroughly cleaned of dust and dirt with special detergents. If dirt particles are not removed, they can cause further damage to the surface of the headlights during sanding. In order not to damage parts of the body adjacent to the lighting fixtures with abrasive compounds, it is recommended to dismantle the headlights before processing.
There are several ways to polish headlights with paste. Processing can be done manually or with a drill with a special felt attachment. Damaged surfaces must be treated for 3–5 minutes to achieve the maximum positive effect. Periodically you need to clean the headlight of excess abrasive substances and dust with a dry cotton cloth to evaluate the results of polishing. Processing continues until the headlight becomes completely smooth.
If grinding did not restore the original transparency of the headlight, it means that it also has defects on the inside. They occur under the influence of elevated temperatures when using xenon or halogen lamps, causing the inside of the headlamp to become cloudy. To restore the transparency of the device, you will have to completely disassemble the headlight and polish it from the inside. Glass headlights do not require polishing from the inside; they simply need to be treated on the outside and then washed with glass washing liquid.
It is important to note that the surface of modern plastic headlights often has a special protective coating that is erased during grinding. Therefore, immediately after processing and cleaning the lighting devices, they need to be re-coated with a special transparent varnish in several layers. Complete drying of such varnish occurs no earlier than a day after application.
3 Is it possible to use Goya paste to treat car windows?
While the car is moving, dust, particles of dirt and debris, carried by oncoming air currents, constantly fall onto the outer surface of the interior glazing. They can damage glass and negatively affect its smoothness and transparency. The windshield receives more serious damage when colliding with small stones flying out from under the wheels of oncoming vehicles.
Glass also gets scratched when using power windows due to dust and sand particles getting stuck on the inside of the seals. And the windshield is scratched by grains of sand deposited on the windshield wipers. You can damage the glass surface with your own hands if you use excessive force when cleaning the glass with a scraper of snow and ice.
GOI glass polishing paste should be used only if you are confident in your abilities and will not allow scratches to appear during use. All this leads to cracks, scratches and dulling of the glass, which impairs the visibility and appearance of the car. Minor damage to glass (up to 300 microns) can be effectively eliminated using GOI polishing paste. However, grinding cannot be carried out if there is significant damage; such work can lead to curvature of the glass surface and an even greater loss of transparency.
Before processing, glass must be thoroughly washed and dried. It is best to mark areas with damage on the inside with markers, and adjacent parts of the body, hood and roof should first be protected with masking tape. Polishing glass manually and especially using electric tools should be done very carefully and carefully. Any sudden movements can damage the glass or other parts of the car.
4 How to properly dilute and use abrasive paste?
Before polishing the car with the purchased paste, the abrasive agent must be softened. In its original state, this material is too dry, which makes it very difficult to apply to a polishing cloth, and hard lumps of paste can damage glass and other vehicle parts.
To soften the paste, you can use different liquids, from motor oil and distilled water to refined gasoline and white spirit. We do not recommend using flammable chemicals to dissolve the paste. With them, you not only expose yourself to danger, but also endow the treated machine parts with a pungent odor that will be difficult to get rid of.
In its normal state, GOI paste is very dry, which prevents it from being easily applied to a polishing cloth. The easiest way is to dilute the paste with motor oil, a few drops of which should be applied to a hard abrasive block using a pipette or syringe. Use a cotton or flannel cloth to rub the liquid into the block until the paste becomes similar in consistency to plasticine. In this form, the product no longer poses a danger to the surfaces being treated.
To increase the homogeneity of the resulting paste, the mixture of GOI with motor oil can be slightly heated in the microwave and mixed thoroughly.
The principle of polishing surfaces with a paste is that the small particles contained in it remove the thinnest layer of plastic or glass along with the microcracks present on them. The prepared paste is applied to a cloth or polishing wheel and rubbed a little on hard surfaces to remove solid particles. Then the surface with existing damage is processed with reciprocating movements with the next strip partially overlapping the previous one. After this, it is allowed to treat the surface with a cloth or in a circle in a spiral direction from the edge to the center.
The surface to be treated must be damp, and during processing it must be periodically wiped with a wet cloth. Cleaning from dust will also allow you to monitor the condition of the processed part. To polish with a grinder, use a power tool at medium speed - less than 1000 rpm. Glass and other materials should be processed with smooth movements, without stopping in one place. The abrasive wheel should be positioned at an angle of less than 5 degrees to the surface being treated in order to have maximum contact with the workpiece. If the part becomes very hot, processing should be stopped. It is better to repeat polishing every year or two so that important elements of the car remain operational.
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