Since most stones are mined in the form of a shapeless massive rock, they need processing, which will make it possible for their further use in a particular area. The exception is rocks that have natural decorative value (boulder, pebbles, coral, pearls, etc.). Various textured processing of natural stone gives it an aesthetic appearance, helps to reveal and emphasize decorative properties, or hide imperfections.
Modern technologies for processing natural stone
Mechanized stone-cutting production allows you to process any rock and give its surface the required texture after mining and sawing. There are the following technologies for processing natural stone to obtain the desired surface texture. Some of them can be found below.
Sawn surface - obtained by cutting the workpiece. For this purpose, machines with linear movement of the saw frame, band, rope and circular saws are used. The surface becomes rough with intermittent grooves up to 5 mm deep.
Surfaces with this texture are used for paving areas, garden paths, cladding plinths and walls. In addition, these products are used as a material for subsequent, finer processing - polishing, grinding, glazing.
Grinded surface - is formed as a result of processing the workpiece with grinding wheels, on portal and bridge type machines, grinding and polishing conveyors and grinding and polishing machines for volumetric products. The surface acquires a uniform roughness, with relief irregularities up to 0.5 mm high. This technology is applicable for light-colored breeds with an undefined pattern. It is not suitable for dark, especially patterned rocks, as it significantly hides the pattern and color.
Such products are used for finishing floors, platforms, steps of stairs and places where it is necessary to reduce slipping.
Polished texture - achieved by using special grinding wheels coated with micro-grinding powders. The surface is smooth, but does not have a mirror shine. Polishing opens up the design well, highlighting the structure of the stone.
The slabs obtained in this way are used for cladding the floor plane and external walls of buildings.
Polished - achieved by subsequent grinding of the polished surface on a conveyor with powder-coated wheels, and then with felt and fabric wheels. The use of Goi paste or tin nitrate gives the polished stone a special shine.
Polishing perfectly reveals the pattern of the stone and emphasizes the color.
This material is used for interior decoration, the production of window sills, countertops and other interior elements.
Conchoidal - has uniform depressions from 1 to 4 mm deep, giving the stone a special decorative appearance.
Slabs with this texture are used for exterior decoration of buildings and for interior design.
Melted - obtained as a result of the use of thermal technology for processing stone on a thermal gas-jet machine. It reveals texture and color well, while creating the impression that the stone is slightly melted.
Products after heat treatment used for finishing building facades, staircases and landings.
Rocky surface texture - is an imitation of roughly processed rock with the presence of depressions and protrusions from 50 to 200 mm, located in a chaotic manner and not undergone additional processing. The effect is achieved by chipping rock from a previously weakened surface.
A material with such a texture is used for finishing the facades of large buildings, emphasizing their significance and monumentality, as well as their natural connection with the surrounding landscape.
Common methods of processing natural stone
Modern methods of processing natural stone are divided into 2 types: mechanical and physical-mechanical.
Mechanical methods include the most common methods to date such as chipping, impact destruction and cutting.
When chipping, the following is achieved: the texture of a flat and relief “rock”, lumpy, characterized on the front surface by the presence of evenly distributed depressions and bumps; texture and texture is relief, with the presence of parallel grooves with a height of 0.5 to 3 mm.
Cutting is the most common modern method of stone processing. It is carried out using the disk, rope or strip cutting method.
Strip sawing is divided into sawing using steel and cast iron shot and diamond-strip sawing.
Disc sawing is becoming increasingly widespread in the processing of rocks of any hardness and is divided into disc and diamond disc sawing with cutters.
Rope sawing has become widespread when cutting rocks of various densities. Its development is proceeding in 3 directions: wire sawing with the help of abrasives, diamond wire sawing and sawing with ropes reinforced with carbide washers.
Impact destruction of stone is most widely used in the production of hewn products. Most often, steps, monument bases, bridge abutments and other elements are made in this way, where a dotted texture of processing is achieved.
The method of ultrasonic decorative processing of stone in an abrasive environment is beginning to occupy a worthy place in the industry. The process is very slow, but characterized by very high accuracy.
Physical-mechanical methods include treatment with high-frequency currents and the widely used method of processing stone with thermosetting gas burners of kerosene-oxygen and gasoline-air types, which is used for the production of architectural and construction parts and the manufacture of monuments from high-strength rocks.
The high-frequency current method is most suitable for processing blank blocks in the production of curbs, parapets, steps, etc. This method, when using high-frequency oscillations up to 20 MHz, is considered the most accurate and promising.
Processing natural stone at home
According to the degree of difficulty, all stones are divided into soft and hard. Soft stones can be easily processed with the same tools as metal products, while hard stones require the use of special tools. Stone processing at home requires a separate room equipped with exhaust ventilation, since work such as cutting and grinding is accompanied by a large amount of stone dust, which is very harmful to health.
At home, to process natural stone, you can carry out such work as: cutting, grinding, polishing the stone and engraving. It is important to remember that cutting, grinding and polishing stone is carried out only with a continuous supply of water. Water cools the cutting element, removes sludge generated during operation and significantly reduces the level of stone dust.
Cutting - rough is carried out using a regular grinder and a stone disc. A more accurate one will require the use of a sawmill type machine with a metal, preferably movable, platform.
Grinding is carried out using a grinding machine (manual or stationary) or an angle grinder with appropriate grinding wheels. The simplest method of grinding, but only for stones up to 20-25 cm in length: pour abrasive powder onto a cast-iron plate and fill it with water, place the stone on top and rub until it reaches the desired surface. The fine-grained structure of cast iron facilitates stone processing.
Polishing is performed using special polishing wheels and Goi paste.
Engraving is possible when using a device for performing precision work, or using a set of stone cutters and a hammer. In this case, the engraving must be polished using an electric drill and polishing attachments.
A homemade machine for polishing stones, rings, cufflinks and other jewelry - in each of these products, stones play the role of a sculptural, artistic and building material, and also serve as the main detail of an applied artistic composition.
Do you think we're talking about about precious stones? No, the simplest ones.
The stone will not reveal its beauty to everyone - it reveals it only to those who are patient. But how much effort must be put in to correctly cut the stone, grind and polish and process it to get the intended shape.
For this work, the stones give a picture of thousands of years, it comes to life and delights with magical shades and tints. If a person can at least once achieve such a result himself through manual stone processing with your own hands, he will fall in love with this business completely and irrevocably.
It all starts with searching for a stone. These can be both minerals and ore rocks. Special attention jasper, agate, crystal brushes and flint were awarded. But this is just the beginning. Next comes processing, during which the stone is cut with cutting discs, which can be found in any diamond tool store. Hobbyists prefer discs with a diameter of 125 to 200 mm and use them on a motor with a power of 150-200 watts via a belt drive. After cutting, it is important to cool the blade on both sides.
Making a machine for processing stones at home
Stone cutting machine simple conditions It's not difficult to do. If you look at the design, you can easily understand where the cooling is supplied and where which parts will be located.
Grinding rules
Grinding stones to create flat plates can be done even on plain glass using abrasive powders. You should spray the glass and apply a little powder and you are ready to start. When grinding, the powder is added little by little as the abrasive wears out, and water is needed to maintain the creamy mass.
When, when grinding, you move from a coarser powder to a fine one (by fraction), the glass and hands should be washed well with soap and a brush: if even a little powder of a larger fraction gets into the powder of a smaller fraction, everything will be ruined.
When the stone is ground, it should be polished on a felt/felt mechanical wheel, the diameter of which should be between 140 and 200 mm. During the polishing process, chromium oxide powder and water should be used. The rotation of the circle should reach a speed of 410 to 700 rpm.
This is just one way of processing, although in reality there are many more. For those who have fallen in love with manual processing of stones at home, we would like to offer an excellent design of a machine for processing small stones. Since the scheme is extremely simple, we will only give recommendations.
- We suggest using electric motors for a washing machine as a motor - they are usually single-phase, the power ranges from 190 to 240 watts and they can reach up to 1300 rpm. With such engine characteristics, two-stage pulleys with gear ratios of 1:1 and 1:0.35 can be used.
- The first gear is ideal for processing on faceplates with fixed abrasive material, but the second will be used for processing with loose abrasive.
- Use the V-belt from the Zaporozhets car as a gear shifter. You can make the fastening thread both left and right, the main thing is that when working with a load, the faceplate does not move off the axis.
- The trough for collecting slag should be at least 2 times larger than the diameter of the faceplate, the same applies to the height of the sides. You can attach rubber to the sides of the trough so that if the stone falls out of your hands, it will not break.
- Since all processing is carried out using water, we will need a dropper. The problem is that it is only used when working on a faceplate with a fixed abrasive. When using bulk abrasive, it is better to wet the stone in a separate bath, the availability of which should be taken care of in advance.
- And, of course, you should have not just one faceplate, but a whole set: wooden, cast iron, metal with felt and felt attached. This is required for various stages of processing and polishing.
Dry cleaning
Dry cleaning can be used to remove surface deposits. Its advantages are that the samples practically do not suffer from chips and scratches. When processing stone at home, you can use a 5-15% solution of oxalic/hydrochloric acid.
Important: Before using these acids, make sure that the minerals being treated are not soluble in it. Aragonite and azurite cannot be treated with acid.
When processing lapis lazuli and turquoise, you should be careful, since they, although slowly, also dissolve. To soften organic residues, stones are soaked in acetic acid. Fat compounds are easily removed with acetone and gasoline.
Some household chemicals are highly effective for dry cleaning, for example, Antikipin, which perfectly removes carbonate limescale shells from minerals. For hard-to-reach areas, use Progress detergent. In the final stages of processing, chemical minerals can be cleaned with glass and crystal cleaners.
The effect will also be from a “chemical bath”, i.e. you boil the mineral in a pressure cooker. Thanks to this technique, steam will penetrate even into places inaccessible to humans. After processing, the stones should be rinsed well under running water.
Cutting and splitting
Stones that have already been washed and cleaned should be sorted. Some people only collect beautiful specimens or fossils, rare species. Most subjects all the found material to polishing, which helps to reveal the beauty of the stones, and people experienced in this matter sometimes find planes in the sand that, when cut, reveal a picture of the play of colors, bizarre landscapes and even portraits.
As a result, some people simply collect stones, while others use them for crafts, combining them with wood and metal.
But before you start, you should split the stone and remove the excess. For this process (preparation), we will make a special device that will help in working with large samples. We will need a clamp with two teeth made of hardened metal (alternatively, use a vice in which 2 corners with teeth made of pobedit will be mounted).
The stone should be cut with diamond wheels or saws
The grinding and cutting machine can be made on the basis of an electric drilling device or an EZS-1 sharpener. In this case we will have 2 shaft outputs, one of which will have a 6 chuck and the other an emery wheel or a diamond coated wheel. The power of such a device will be 250 watts, and the rotation speed will be ~ 2750 rpm.
To process stones for jewelry at home, you can use other electric motors, the power of which will be in the range from 250 to 500 watts and the rotation speed from 1400 to 3000 rpm. Use a box with a hinged lid as a stand for the machine. The machine itself should be bolted to the cover. This modification of the working tool will allow you to install the machine at an angle.
A side table is attached to the box on the chuck side. Its height can be adjusted so that you can work with circles of different diameters. We place a 2.5*2.5 cm duralumin corner bar on the side table. A protective guard from the cutting wheel should be installed on the side. We draw a middle line along the protective fence and table, which will help when positioning the stone for cutting.
The stands and supports of the side table should be covered with felt or rubber to insulate the machine
You will also need a tray of water to cool the cutting wheel, which we will place under the side table. To reduce friction when cooling, use soap solution. Place another pan of water under the faceplate.
When cutting stone, it is fed along a panka guide, which can be adjusted to the thickness of the plate that will be cut. The stone is fed only towards the cutting wheel. Cooling with water can be done in the form of a moistened piece of foam rubber, which should be held in the left hand on the side of the cutting wheel, since the right hand will feed the stone.
If the stone is large, it is better to hold it with both hands, and press the foam rubber and pebble against it. For additional stability, the edge of the stone is cut off, resulting in a supporting platform. If this option does not suit you, the stone can be installed in cardboard box according to size, fill with cement mortar and after hardening, cut the stone with. When the cutting is finished, carefully remove the cement. It can be difficult to cut a large stone, so you should first cut it and insert three blades made of thin steel plates into these grooves. Thanks to this, you will be able to cut stones whose dimensions are slightly larger than the diameter of the cutting tools.
If there is a need to cut cracked stone
Before the process, it should be glued with epoxy glue. On a wet surface, outline the cracks with a pencil - this will make them easier to see. Before gluing, the stone is dried so that there is no water in the crack. To do this, heat the stone on an electric stove, and then cool it to 60 degrees Celsius. Apply glue to the stone that has not yet cooled down with a stick or brush so that it penetrates deeper and hardens. After this, the stone will be strong enough that it can be safely cut even into thin slices.
Grinding
For a brighter color, carefully polish the cut of the stone. It is fashionable to perform it on a machine, which we proposed to make for splitting and cutting. To make sanding easier, place the stand cover at an angle. Use diamond-coated faceplates for this process, but abrasive wheels (rubberized) will also work.
The last option is good because you can make grooves in them - this will make it easier to grind round stones. In addition, they are much safer to operate. But there are also disadvantages: during operation, they produce a lot of dirt due to rapid wear, and sometimes even scatter into small particles during operation. It is for this reason that, while observing safety precautions, they should be covered with dense steel casings. To do this, you can use an unnecessary aluminum bowl, in which you must first remove the bottom.
The first stage of stone processing by grinding is carried out on a wheel with a large abrasive/diamond grain from 350 to 60 microns, and the second on a wheel with a grain from 60 to 37 microns, and the last - from 37 to 10 microns.
When sanding, you will also need a continuous supply of water, so as in the case of cutting, you can use a piece of damp foam. Ideally, a tank with a tap and a rubber hose will be installed above the machine, through which water will flow drop by drop into the pan. To prevent splashing, use a bowl guard.
Polishing
The main tools for the final stage of “Polishing” are laps, polished circles made of fabric and felt, and brushes made of plant materials (can be made of jute). Lappings are the most important tool that brings the surface of a stone to its ideal appearance. They come in manual and planchet form. The material for stone processing can be any: tin, cast iron, wood, lead, hematite, fluoroplastic, chalcedony.
As a rule, they are needed for fine grinding, and when polishing, GOI paste or moistened chromium oxide is added. Instead of the latter, you can use green paint with the same name, since oxide is the main component in its composition. Polishing using it is carried out with a leather swab. But GOI paste and oxide have their drawbacks - they eat into the cracks of stones and are very difficult to remove even with gasoline. Aluminum oxide powder can be used for polishing.
Other DIY stone processing technologies
As we already understood, achievement different textures stone gives different effects.
Let's look at several popular types:
Gems in jewelry in its original form is rather an exception. To reveal the beauty of the mineral, it is processed. And only then does the gem become part of a spectacular accessory.
Natural minerals without defects are very rare and expensive. Processing and refining of stones improve their qualities and increase their value: color, purity and saturation. As a result, the cost of jewelry is often determined by the stone. The processing method depends on the properties of the mineral: its size, hardness and purity. Let's tell you in more detail, how gems are improved, making them truly majestic.
Stone processing is a craft that has been developing since ancient times.
Methods and types of processing: history and modernity
the main task in the process of working with a precious stone, preserve the integrity and mass of the mineral as much as possible.Processing stages:
1. Marking- identification of inclusions, determination of weight and type of cut. Today this process occurs using 3D laser scanning.
2. Sawing- dividing the stone into parts with diamond powder. In ancient times, when necessary, minerals were simply split.
3. In progress sanding and roughening remove excess weight and give basic shape.
4. Cutting, grinding and polishing.
Diamond cutting process
Cutting methods have improved over time. The oldest of them is the cabochon. And here facet grinding(cut) has been known since the end of the 13th century. Cabochon- a method of processing stones that do not transmit light. The result is a smooth, convex stone without edges, obtained during processing in a tumbling drum.
Cut- processing of a mineral in the form of a polyhedron. My first memories are connected with Venice. During the modern period, Antwerp and Amsterdam became the centers of cutting. In Russia, the art of stone processing has spread since the 18th century.
Facets (facets) are applied to the mineral so that light rays are refracted and create a beautiful glow
Gemstone grinding
Cutting diamonds and other gems. For a long time, stones were not cut, but only polished: they rubbed one mineral against another. In India, this was done using diamond powder, which was applied to a rotating metal disk. From the 14th century, European craftsmen began to saw off the upper part of the stone, obtaining a flat platform; in the 15th century, the lower part as well.
There are main types of stone cutting:
- stepped;
- wedges;
- rose;
- fantasy;
- cabochon;
- combined.
In addition to cutting, since ancient times, gems have been processed using the technique glyptics(stone carvings). Inscriptions and images were scratched onto the surface of the mineral. This is how cameos (brooches with a convex image) and decorative objects are made. Initially, stone carving was done on slabs, where the mineral was shaped with powder from other hard rocks, and a design was applied with iron cutters or fragments. The first seals with carvings have been known since the 3rd century BC. e.
Types of stone cuts
Stone refining is a process of improvement
Modern stone processing technologies include oiling, temperature exposure, crack filling, irradiation and painting. Different stones can undergo only one type of processing or several.
Oiling- a method of impregnating a stone with colorless oil to improve the purity and color of the mineral. Most often, cedar oil is used for emeralds of the highest category; other stones are treated with synthetic materials.
Heat treatment (annealing) in a special oven - the most common method of processing stones, improving its color and quality. During the annealing process, inclusions are removed (ruby), a star effect is obtained (sapphire), lightening (tourmalines), and color is fixed (blue zircons).
Filling the stone with paste, prepared on the basis of the same mineral. It is made by grinding another crystal into dust. Mainly used for corundum. The stones are baked in a paste that displaces moisture and air, filling them.
Irradiation used to change the color of diamonds, quartz and topaz. Apply different types irradiation: ultraviolet, x-ray, gamma radiation or energetic particles: neutrons, protons, electrons.
There are also other processing methods: bleaching (pearls), laser drilling (bleaching inclusions in a diamond), coating stones with wax, varnish or enamel.
The photo shows the difference between the processed and uncut stone
Thanks to processing, raw materials in the form of an uncut mineral are transformed into a work of art. In the skillful hands of a jeweler, the stone begins to sparkle and acquires real beauty: deep rich color, play of light on the edges. The catalog contains thousands of jewelry with bright and shiny gems set in precious metals. This nice gifts for loved ones who will treasure the best moments and emotions forever.
Rings with radiant gems and inserts, pendants, earrings, cufflinks and other jewelry with stones. Writing instruments, sculptures, columns and plinths and walls of buildings. In all these examples, and not only in them, stones perfectly fulfill the role of artistic, sculptural and construction frames, serving main detail for arts and crafts composition. Stone lovers collect all minerals, including ore rocks. For example: agates, jaspers, silicon and transitional forms of these minerals. Today you will learn how grinding occurs precious stones at home.
Former beauty
We will restore the stone to its former beauty using the following materials:
- Sandpaper with different grain sizes.
- Soft cloth or polishing pads (for machining).
- Special chemistry for stone.
- Grinding wheels.
- Sand.
All polishing is divided into stages, each stage will be described in order.
Cleaving or cutting
Cleaned and washed stones must be sorted.
Important! Experienced amateurs who know their craft find such planes of cuts in the stone through which one can see the play of colors reminiscent of landscapes, or even portraits.
Before you start working on the craft, you need to:
- Chop the stone and remove all excess.
- For splitting (preparing) large samples, special devices should be made: a clamp with two teeth made of hardened metal or a vice in which two corners with pobedite teeth are mounted.
- The stone is cut with special diamond wheels or commercially available diamond saws.
The cutting and grinding machine can be assembled on the basis of an electric sharpener or an EZS-1 electric drilling device.
Important! It has two shaft outputs, one equipped with a chuck 6, the other with an emery wheel or a special faceplate, with a diamond coating. The power of this EZS-1 device is 0.25 kW, rotation speed is 2800 min.
Other electric motors can be used for stone processing in the power range from 0.25 to 0.5 kW and rotation speed from 1500 to 3000 min. Installation of the device takes place with the expectation that you will need to manipulate different sizes of disks and angles of inclination. 
What to consider when working:
- To soundproof the machine, the bottom of the stand box and the supports of the side table are covered with rubber or felt.
- A tray of water is placed under the machine's side table to regularly cool the cutting wheel.
Important! To reduce friction, you can add a soap solution to the water.
- The second water pan is installed under the faceplate.
- When cutting, the stone is fed along a guide bar, the position of which is adjusted to the thickness of the plate of the element being processed, which is about to be cut.
- The stone is fed towards the rotation of the cutting wheel, everything is simple here.
- Water for cooling the wheel can also be supplied using a moistened piece of foam rubber, which is held with the left hand at the side of the cutting wheel.
Important! With the right hand they give the stone. It is better to hold large elements with both hands, and press the foam rubber together with the stone against the tool.
- For stability, the edge of a natural rock element is first cut off to obtain a supporting platform.
Important! As an option, you can also install the stone in a specially prepared cardboard box, fill it with cement and, after complete hardening, cut the stone together with the cement box. If you used this type of cutting, the cement is carefully removed when it is finished.
- To cut a larger stone, it is scored and three wedges of thin steel plates are driven into the cut grooves. The material is broken by carefully hitting it with wedges.
Important! This method is convenient for cutting elements whose size is slightly larger than the diameter of the cutting tool.
- If you have a cracked element of a species that is valuable to you, then before cutting it, glue the defective areas with epoxy glue. Cracks are outlined on a wet surface with a pencil - this way they can be seen better.
Important! Before gluing, the stone must be dried so that no water remains in the cracks. This is done like this: it is heated over an electric stove, and then cooled to about 60 ° C. Epoxy glue is applied to the hot material with a brush or cotton swab along the marked cracks, so it penetrates deeper and hardens faster. The stone becomes quite durable, and as a result, its cutting will be better.
At home, an ordinary grinder and a stone disc are also used. More precise processing of your item will require the use of a sawmill type machine with a metal, preferably movable, platform.
Grinding
When sanding, sandpaper (coarse grain) is used; in addition to paper, sand or pumice is used. This stage ends when you see a flat horizon on the surface.
Important! Often you have to remove 3-4 cm.
You can grind either manually or using, for example, an angle grinder (grinder).
Polishing
Following sanding, it’s time to polish and polish the stone. At home, special products such as polish or wax are used to treat stone.
Surface treatment
Now you need to coat the cobblestone with a protective and decorative agent. There are many products on the market with different properties: some highlight the structure of the rock, some give the material a “wet look”.
The main thing when choosing is not to be fooled by prices, but to ensure that your efforts do not go down the drain, because a low-quality product can do just that.
Important! Some substances in the composition may react and ruin the item of your pride.
Engraving
Engraving is possible when using a tool for performing point work, or using a set of stone cutters and a hammer. In this case, after completing the engraving, you need to polish the stone using an electric drill and polishing attachments.
After gaining this knowledge, you are ready to polish the stone at home. Again, safety precautions should be kept in mind. If you are not confident in your abilities and have never had experience, it is better to use the services of professionals in this matter. This process is quite labor-intensive and complex, so you need to prepare properly and then start.
Continuing the stone processing topic, which we touched on in the previous article “Extraction methods.” Dimensions and fractions,” I would like to talk separately about the methods and methods of texture processing of the surface of natural stone. It is worth mentioning right away that not all stones can be processed in all ways. Since all rocks differ in structure and texture, there are suitable and inappropriate processing methods for each of them. There are more than a dozen types of processing in total, and we would like to characterize the most popular of them in a brief, abstract form. So:
Sawing- achieved by sawing the workpiece. The cut surface remains unevenly rough, with so-called grooves up to 2 mm high. Sawing with steel shot gives additional relief, while special reinforced plates made of hard alloys, on the contrary, smooth it out. It is both the primary processing, followed by the final one, and the final one. Sawn slabs find their use in landscape design (for the design of walking garden paths and adjacent areas, artificial ponds), in finishing works for cladding plinths, interior cladding of premises, and are also used as a decorative element (fireplaces, entrance lobbies, walls).
Grinding - the process of leveling a solid material using abrasives to a uniformly rough surface (traces of processing are visible). It is performed in several stages (from 3 to 7). At each stage, different grinding attachments are used with a gradual reduction in abrasive grains. The maximum permissible unevenness is up to 0.5 mm. The quality of grinding is influenced by such characteristics as workability (see article Qualitative characteristics of natural stone). Polished slabs are used where it is necessary to increase friction, thereby reducing slipping, and these are flights of stairs, floors, pedestrian areas
Polishing(fine grinding) - maximum smoothing of the plane with a grinding tool sprayed with micro-grinding powders. In other words - improved, smooth sanding or polishing without shine. Tool marks are not visible, the surface is matte with a slight velvety shimmer, the natural pattern is clearly visible. Polishing is widely used for the manufacture of floor slabs and slabs for external/facade cladding of buildings.
Polishing- maximum smoothing of the surface to a mirror shine and clear reflection of the details of objects (without traces of previous processing). There is chemical polishing and mechanical polishing. For chemical polishing, special compounds are used - GOI paste (chromium oxide) or tin nitrate, and for mechanical polishing - felt or felt circles. Each stone has its own maximum gloss level, beyond which the polishing quality does not improve. The standard is considered to be the maximum gloss of glass, which is 200 units. Polishability can be:
- Excellent- 170-200 units. - full-crystalline marbles, fine-grained granites, quartzites.
- good- 140-170 units. - granites, marbled limestones.
- Average- 70-140 units. - basalts, limestones, dolomites.
- Bad- less than 70 units. - tuffs, loose limestones. (see article Qualitative characteristics of natural stone)
Polishing reveals the natural texture of the stone - color and pattern. The most common type of treatment, suitable for both interior and exterior decoration.
Heat treatment/ Burning / Melting - Stone surface treatment (mostly granite) flame high temperature(2300 -2700ºС) until a rough surface with traces of peeling is achieved. When exposed to fire, some of the minerals melt and burn out, resulting in the formation of small depressions and mounds. The graininess of the resulting texture depends on the size of the granite crystals and the duration of exposure of the flame to the surface.
Heat-treated stone is often used in road construction, landscaping of local areas, as well as for the design of entrances and staircases, that is, where it is necessary to reduce slipping.
Skol(“Rock” texture) - chipping of the top layer of the surface with special wedges to imitate roughly processed stone or even unprocessed natural chipping with chaotic depressions and bulges. More often, the chipped texture is found in the external cladding of buildings (effectively emphasizing the monumentality of large buildings), as well as when solving various problems of landscape design, it fits harmoniously into the natural landscape.
Bush hammering- a processing method to impart a uniformly rough surface with a maximum permissible relief unevenness of up to 5 mm. Processing is carried out on impact machines and using special attachments - bush hammers (historically, a bush hammer was a hammer with a working surface in the form of teeth, designed for impact chipping of the surface of natural stone; today, a bush hammer is a special attachment for a stone-processing machine, repeating the essence of a historical hammer). This processing method is used when it is necessary to remove the top worn layer of stone for renewal, as well as in finishing work in the form of flooring, where it is necessary to reduce slipping.
Brushing- the essence of the treatment is the same as with bush hammering - giving a uniformly rough surface and an aging effect, but is achieved with the help of special brushes, not bush hammers.
Galtovka- the process of stone processing in special tumbling drums or tumbling vibrating machines. The stones, together with the filler (arbaziv), are placed in machines, where, when exposed to sharp corners and edges, they are chipped and smoothed. The result is a smooth surface with smoothed edges - the effect of a stone that has been in moving water for a long time. The result of natural tumbling is pebbles.
Sandblasting and waterblasting- abrasive methods in which sand or other fine abrasive material is sprayed either with a high-pressure air stream or with a stream of water, cleaning the surface and giving it a uniform roughness.
Split- the oldest method of interaction with stone and its processing, based on pinching/separation of a slab-like piece of rock from the main mass along natural fibers, as well as splitting stone raw materials into thinner and more convenient tiles for further work (flagstone). It is not suitable for all rocks, but rather only for a number of certain ones that have a layered texture. Flagstone is very popular in landscape design when decorating paths, gazebos, ponds, cladding fences and other home buildings; in the design of building facades, as well as in interiors - they frame entrance lobbies, fireplaces, and decorative panels.
Etching- exposure of the stone surface to chemical reagents. It is used to remove the top layer of rock, clean it, and give a rough surface.
Hydrophobization- treatment with chemical solutions, as a result of which the surface becomes non-wettable.
Fluting- treatment with chemical solutions, as a result of which the pores and capillaries are compacted and, as a result, water absorption is reduced, strength and frost resistance are increased.
We hope that we were able to convey the nuances of surface treatment methods, characterizing them from the technical side of execution and from the point of view of the achieved result.
Let us remind you that not every method is suitable for every type. rock and suitable for any product or use.
