One day in 1903, the French chemist Edouard Benedict was preparing for another experiment in the laboratory - without looking, he reached out for a clean flask that was on a shelf in the closet and dropped it. Taking a broom and a scoop to remove the fragments, Eduard went to the closet and found with surprise that the flask, although it had broken, all its fragments remained in place, they were connected to each other by some kind of film. The chemist called a laboratory assistant - he was obliged to wash glassware after the experiments - and tried to find out what was in the flask. It turned out that this container was used a few days ago during experiments with cellulose nitrate (nitrocellulose) - an alcohol solution of liquid plastic, a small amount of which, after the alcohol evaporated, remained on the walls of the flask and froze with a film. And since the plastic layer was thin and transparent enough, the laboratory assistant decided that the container was empty.
A couple of weeks after the story with the flask that did not shatter into fragments, Edward Benedict caught the eye of an article in the morning newspaper, which described the consequences of head-on collisions of a new type of transport in those years - cars. The windshield shattered into fragments, inflicting multiple cuts on drivers, depriving them of vision and normal appearance. The photographs of the victims made a painful impression on Benedict, and then he remembered the "unbreakable" flask. Rushing to the laboratory, the French chemist dedicated the next 24 hours of his life to creating unbreakable glass. He applied nitrocellulose to glass, dried a layer of plastic, and tossed the composite onto the stone floor—over and over and over again. So Edward Benedict invented the first triplex glass.
laminated glass
Glass formed by several layers of silicate or organic glass connected by a special polymer film is called triplex. Polyvinyl butyral (PVB) is commonly used as the glass bonding polymer. There are two main ways to produce triplex laminated glass - pouring and laminating (autoclave or vacuum).
Filled triplex technology. Sheets are cut to size, if necessary, they are given a curved shape (bending is performed). After thoroughly cleaning the glass surfaces, they are stacked on top of each other so that there is a gap (cavity) between them no more than 2 mm high - the distance is fixed using a special rubber strip. Combined sheets of glass are set at an angle to a horizontal surface, polyvinyl butyral is poured into the cavity between them, a rubber insert around the perimeter prevents it from flowing out. To achieve the uniformity of the polymer layer, the glasses are placed under a press. The final connection of glass sheets due to the curing of polyvinyl butyral occurs under ultraviolet radiation in a special chamber, inside which the temperature is maintained in the range from 25 to 30 ° C. After the formation of the triplex, a rubber band is removed from it and the edge is turned.
Autoclave lamination of triplex. After cutting glass sheets, processing edges and bending, they are cleaned of contamination. Upon completion of the preparation of float glass sheets, a PVB film is laid between them, the formed “sandwich” is placed in a plastic shell - air is completely removed from the bag in a vacuum installation. The final connection of the “sandwich” layers takes place in an autoclave, under a pressure of 12.5 bar and a temperature of 150 ° C.
Vacuum lamination of triplex. Compared to autoclave technology, vacuum triplexing is performed at lower pressure and temperature. The sequence of working operations they have is similar: glass cutting, shaping in a bending furnace, turning edges, thorough cleaning and degreasing of surfaces. When forming a “sandwich”, an ethylene vinyl acetate (EVA) or PVB film is placed between the glasses, then they are placed in a vacuum machine, previously placed in a plastic bag. The soldering of glass sheets takes place in this installation: air is pumped out; "sandwich" is heated to a maximum of 130 ° C, the film polymerizes; the triplex is cooled to 55°C. Polymerization is carried out in a rarefied atmosphere (-0.95 bar), when the temperature drops to 55°C, the pressure in the chamber equalizes to atmospheric pressure and, as soon as the temperature of the laminated glass reaches 45°C, the formation of the triplex is completed.
Laminated glass, created by poured technology, is stronger, but less transparent than laminated triplex.
Windshields of cars are made from glass sandwiches made using one of the triplex technologies, they are necessary for glazing high-rise buildings, in building partitions inside offices and residential buildings. Triplex is popular with designers - products from it are an integral element of modern style.
But, despite the absence of fragments when hitting a multi-layer "sandwich" of silicate glass and polymer, it will not stop the bullet. But the triplex glass discussed below will do this quite successfully.
Armored glass - history of creation
In 1928, German chemists create a new material that immediately interested aircraft designers - plexiglass. In 1935, the head of the Research Institute "Plastmass" Sergei Ushakov managed to get a sample of "flexible glass" in Germany, Soviet scientists began to study it and develop mass production technology. A year later, the production of organic glass from polymethyl methacrylate began at the K-4 plant in Leningrad. At the same time, experiments were begun aimed at creating armored glass.
Tempered glass, created in 1929 by the French company SSG, was produced in the USSR in the mid-30s under the name "stalinite". The hardening technology was as follows - sheets of the most common silicate glass were heated to temperatures in the range from 600 to 720 ° C, i.e. above the glass softening temperature. Then the glass sheet was subjected to rapid cooling - cold air flows lowered its temperature to 350-450 ° C in a few minutes. Thanks to tempering, the glass received high strength properties: impact resistance increased by 5-10 times; bending strength - not less than twice; heat resistance - three to four times.
However, despite its high strength, "stalinite" was not suitable for bending to form an aircraft cockpit canopy - hardening did not allow it to bend. In addition, tempered glass contains a significant number of internal stress zones, a light blow to them led to the complete destruction of the entire sheet. "Stalinite" cannot be cut, processed and drilled. Then the Soviet designers decided to combine plastic plexiglass and "stalinite", turning their shortcomings into dignity. The pre-molded aircraft canopy was covered with small tiles of tempered glass, with polyvinyl butyral as the adhesive. 
The entry of the former Soviet republics into capitalism since the early 1990s has sharply increased the demand for armored glass protection for vehicles of collectors and currency exchange offices. At the same time, there was a need for "transparent armor" for business cars. Since the production of real armored glass was expensive, as well as the final product, a number of companies launched the production of imitation armored glass - it was a triplex of rather mediocre quality, the polymerization of PVB film was carried out in an accelerated mode, using ultraviolet irradiation. The finished product was able to withstand a pistol bullet from a distance of 5 meters, i.e. corresponded only to the 2nd class of protection (there are six in total). Massive armored glass of this type could not withstand temperature fluctuations of more than +20 and below -22 ° C - after six months, the layers of triplex partially delaminated, their already low transparency was seriously reduced.
transparent armor
Modern bulletproof glass, also called transparent armor, is a multilayer composite formed by sheets of silicate glass, plexiglass, polyurethane, and polycarbonate. Also, the composition of the armored triplex may include quartz and ceramic glass, synthetic sapphire.
European armored glass manufacturers mainly produce triplex, consisting of several “raw” float glasses and polycarbonate. By the way, non-tempered glass among companies producing transparent armor is called "raw" - it is "raw" glass that is used in triplex with polycarbonate.
A polycarbonate sheet in such laminated glass is installed on the side facing the inside of the protected room. The task of plastic is to dampen the vibrations caused by the shock wave when a bullet collides with bulletproof glass in order to avoid the formation of new fragments in sheets of "raw" glass. If there is no polycarbonate in the composition of the triplex, then the shock wave moving in front of the bullet will break the glass even before it actually comes into contact with them and the bullet will pass through such a “sandwich” without hindrance. The disadvantages of armored glass with a polycarbonate insert (as well as with any polymer in the composition of the triplex): a significant weight of the composite, especially in classes 5-6a (reaches 210 kg per m 2); low resistance of plastic to abrasive wear; exfoliation of polycarbonate over time due to temperature changes.
quartz glass. It is produced from silicon oxide (silica) of natural origin (quartz sand, rock crystal, vein quartz) or artificially synthesized silicon dioxide. It has high heat resistance and light transmission, its strength is higher than that of silicate glass (50 N/mm2 versus 9.81 N/mm2).
ceramic glass. It is made of aluminum oxynitride, developed in the USA for the needs of the army, the patented name is ALON. The density of this transparent material is higher than that of quartz glass (3.69 g / cm 3 versus 2.21 g / cm 3), the strength characteristics are also high (Young's modulus is 334 GPa, the average bending stress limit is 380 MPa, which is practically 7-9 times higher than similar indicators of silicon oxide glasses).
Artificial sapphire (leucosapphire). It is a monocrystal made of aluminum oxide, as part of armored glass it gives the triplex the maximum strength properties possible. Some of its characteristics: density - 3.97 g / cm 3; average bending stress limit - 742 MPa; Young's modulus - 344 GPa. The disadvantage of leucosapphire lies in its significant cost due to high production energy costs, the need for complex machining and polishing.
Chemically strengthened glass. "Raw" silicate glass is immersed in a bath with an aqueous solution of hydrofluoric (hydrofluoric) acid. After chemical hardening, the glass becomes 3-6 times stronger, its impact strength increases six-fold. The disadvantage is that the strength characteristics of toughened glass are lower than those of thermally hardened glass.
Armored glass frame
The use of armored triplex in glazing does not mean that the opening blocked by it will be bulletproof - a frame of a special design is required. It is created mainly from metal profiles, most often aluminum. In the grooves located along the junction line of the triplex and the frame profile, steel linings are installed to protect the weakest point in the armored window structure from impact or contact with a bullet. 
Protective armor plates can also be installed outside the frame structure, however, this will reduce the aesthetic characteristics of the window. To achieve the maximum level of protection, the frames can be made entirely of steel profiles (linings are not needed in this case), but they will become very bulky and costly.
The weight of an armored window often exceeds 300 kg per m 2, not every building and construction material is able to withstand it. Therefore, the installation of an armored window structure is only permissible for reinforced concrete and brick walls. Opening the sash of an armored window is not easy due to its high weight; servo drives are used for this purpose.
Bulletproof glass- a multilayer structure consisting of several M1 glasses and several layers of a polymeric photocurable composition. Depending on the required protection class, the design can be either with or without a film. This design structure provides protection against bullets fired from different types of weapons, depending on the required protection class.
The armored glass design is transparent and provides protection according to classes B1, B2, B3, B4, B5 (bullet resistance class 1, 2, 3, 4 and 5) according to GOST R 51136-2008 while simultaneously transmitting light. Suitable for both internal and external glazing.
The complete set of a double-glazed window for preservation of a temperature condition is possible.
Armored glass- a guarantee of security, it was created in order to protect people and their property. That is why it is especially important that the glass is of excellent quality. You need to be sure that you and your property are fully protected. The first, second, third, fourth, fifth or sixth class of armored glass protection is selected based on the conditions and wishes of the customer.
Scope of bulletproof glass
- currency exchange points;
- places for issuing money at the cash desks of large organizations, enterprises;
- internal security posts in banks, jewelry stores, shooting galleries;
- workplaces of petrol station operators;
- workplaces of bank tellers working in operating rooms;
- workplaces of employees of duty units of internal affairs bodies;
- equipment of banks and cash collection machines;
- other buildings, structures and objects that need to be protected from burglary, strikes and shelling.
Double-glazed windows made of laminated armored glass, made using mirrored, tinted glass of various colors, have unique properties that not only protect the room from impacts and shelling, but also reduce heat loss in the cold season, protect against the harmful effects of sunlight and noise.
A mirror made of laminated glass, along with high strength characteristics and aesthetic properties, ensures its long-term and safe use in rooms with high humidity (in bathrooms and swimming pools).
Armored laminated protective glass (bulletproof glass) is intended for use on vehicles, in administrative and residential buildings, where there is a need to protect human life and material values.
Characteristics of bulletproof glass
Characteristics bulletproof glass correspond to GOST R 51136-2008 "Protective multilayer glasses". The total light transmission of glass is at least 70%. Glass must be heat and moisture resistant, withstand a temperature of 60 ° C and a humidity of 95%. Its frost resistance is minus 40 °C.
Defensive Ability bulletproof glass depends on its thickness. 37 mm thick glass holds PS-43 bullets of 7.62 mm caliber from AKM. According to the certificate issued by the State Standard of Russia, such glass corresponds to the third class of protection and, in addition, is able to hold bullets from PM, TT pistols, AK-74 assault rifles and fragments from RGD-5, F-1 and RG-42 hand grenades.
Armored glass has protective properties
- withstands repeated impact of a freely falling body;
- resistant to penetration;
- withstands the impact of firearms (PM, TT pistols, AKM submachine gun, SVD rifle) and prevents through penetration of the damaging element.
Technologies for the production of armored glass
For the manufacture of bulletproof glass, flat or curved polished blanks with a thickness of 5 to 10 mm are used. In order to increase strength, they are glued together in a certain combination. Polyvinyl butyral film is used as fastening materials. Then a layer is glued to the inner surface of the glass, which protects against damage by secondary glass fragments. In this way, not only extremely strong, but also shatterproof glass is obtained.
Protective film in armored glass
The protective film has a very high transverse tensile strength. When applied to glass, it gives it the same properties: it greatly weakens deformations transverse to the glass surface, including microvibrations. If even a small transverse deflection occurs, the viscous polymer film quickly returns the glass (providing elastic deformation) to its normal position. Of course, a sufficiently strong impact can deflect the glass with the film from its undeformed position by the distance necessary for the fragile glass to still break. But at the same time, it remains in place, glued to the protective film.
Properties of the protective film of bulletproof glass
- strengthening glass - glass does not break when not too strong blows (when hit by a soft body, foot, stone or bottle);
- shatterproof - the film prevents fragments from entering the room even when the glass does break (therefore, the protective film is applied to the armored windows from the back);
- penetration protection - maintaining the integrity of the window (even after breaking) prevents an intruder from entering the room, providing protection similar to gratings;
- the possibility of listening is almost completely excluded by removing sound vibrations from the glass with special equipment;
- soundproofing properties (sound enters the room through the window due to mechanical vibrations of the glass, retransmitting street noise);
- well absorbs ultraviolet, keeping the interior from fading and providing protection from one type of heat transfer. As a result, the thermal isolation of the premises from the external environment increases and, as a result, the costs of heating the premises in winter and cooling in summer are reduced;
- with similar protective qualities, glass with a protective film can be knocked out from the inside of the room.
Requirements for installing bulletproof glazing
Protective panels must have a stability class not lower than the stability class of the protective glazing used. For class B1 (P1), the panels must be made of sheet steel with a thickness of at least 6 mm. For class B3 (P3) - from sheets of armored alloy with a thickness of at least 4.57 mm.
Trays for transferring money or documents, openings for negotiating must be designed to prevent the penetration of a bullet into the protected area when fired from outside.
Vertical supports must be securely fixed at ceiling and floor level. Horizontal structural members must be securely fastened at each joint and, if possible, fastened to the walls.
Doors to the protected area should provide the same level of protection as the bulletproof glazing used. In addition, they must open outward and be equipped with a self-locking lock.
Any window in the protected area must be protected by bulletproof glazing of the same class as that installed inside the premises.
Test methods for bulletproof glass
The essence of this method is to determine the resistance of laminated glass to the effects of certain types of firearms. The tests are carried out on three samples of laminated glass measuring 500×500 mm. Draw an equilateral triangle at the center of the test specimen with sides 120 mm long. Three shots are fired at the vertices of this triangle. Glass is considered to have passed the test in the absence of through penetration.
Test requirements for bulletproof glass
- the test sample is installed in a rigid frame with clamping devices;
- the rigid frame should not move under the impact of bullets;
- the test sample must be installed perpendicular to the direction of movement of the bullet;
- all four edges of the glass must be evenly clamped, the width of the clamp must be (30 ± 5) mm, while the target area must be at least 440 × 440 mm;
- clamping forces must prevent displacement of the sample during the test, while no stress should occur that affects the result.
Behind the test sample, a fragment storage box is installed, which is a chamber that serves to collect glass fragments separated from the rear surface of the test sample and a bullet that has passed through the test sample.
The bullet velocity measurement device is an electronic system that measures the time of flight of a bullet between two sensors - targets located at a fixed distance of 300500 mm along the bullet's flight path. When a bullet passes through the first target sensor, a pulse is generated, which turns on a frequency meter that counts the number of pulses generated by the high-frequency generator of the device. When the bullet passes through the second target sensor, the pulse is stopped. The speed of a bullet is determined by calculation. The bullet velocity is measured at a distance of not more than 2.5 m in front of the test specimen. The measurement error should not exceed 1.0 m/s.
When a bullet hits an obstacle, the bullet and the protection material itself are damaged: the huge kinetic energy of the bullet's movement is extinguished due to the deformation of the material being compressed and torn by it (inelastic deformation). Most bullets (for submachine guns or rifles) contain a very strong, heavy steel core that, after flattening the shell, penetrates deep into the material.
For the purity of the test, a sheet of thin metal foil is placed behind the test sample, by damage to which the test results can be determined. The protection class depends not only on the means of destruction, but also on the selected cartridge and bullet.
Testing bulletproof glass
- weapons and ammunition are selected according to the protection class for which the laminated glass is to be tested;
- before testing, several preliminary shots are fired to determine whether the actual impact speed is acceptable;
- the sample is installed in the frame with the attacked side to the weapon;
- three shots are fired at the test sample in accordance with the test conditions. The impact speed and the distance between the centers of three impacts are determined with an accuracy of 1 mm;
- inspect the test sample for the presence of through holes;
- check for the presence of glass fragments and fragments that have separated from the rear surface of the test sample in the box - the fragment accumulator;
- the nature of the lesion is controlled after each shot according to the state of the control screen and the back of the sample;
- lumbago is considered through penetration of the sample by a bullet or its fragment;
- glass is considered to have passed the test if there is no penetration of the control screen by a bullet or glass fragments.
Bulletproof glass classification according to bullet resistance
| Glass protection class | Weapon Type | Name and index of cartridge | bullet core type | Bullet weight, g | Bullet speed, m/s | firing distance |
|---|---|---|---|---|---|---|
| B1 - First class of protection | Makarov pistol (PM) | 9 mm pistol cartridge 57-N-181 7.62 mm | Steel | 5,9 | 315±10 | 5 |
| B2 - Second class of protection | Tokarev pistol (TT) | pistol cartridge 57-N-132S or 57-N-134S | Steel | 5,5 | 420±10 | 5 |
| B3 - Third class of protection | AK-74 assault rifle | 5.45 mm cartridge with 7N10 bullet | Steel heat-strengthened | 3,5 | 880±10 | 5-10 |
| B4 - Fourth class of protection | AKM assault rifle | 7.62 mm cartridge with bullet 57-N-231 | Steel heat-strengthened | 7,9 | 715±10 | 5-10 |
| B5 - Fifth class of protection | Sniper rifle (SVD) | 7.62 mm cartridge ST-2M | Steel heat-strengthened | 9,6 | 825±10 | 5-10 |
| B6 - Sixth class of protection | Sniper rifle (SVD) | 7.62 mm cartridge BZ-32 | Steel | 10,4 | 820±10 | 5-10 |
Video about armored glass
The bulletproof glass video was commissioned by the How It Works program.
Glass that is not afraid of a hammer! Does it happen?
Today I will tell you about how to protect your office, store or apartment from entering them through windows on your own.
The issue of security and protection of their property worries every person. If your apartment or office is located on the first or basement floor, then windows are one of the most vulnerable places. The fact is that the window, which is located at the level of human growth, is a great temptation for spontaneous theft. And even if the room is equipped with an alarm, this will not prevent the attacker from grabbing something valuable and hiding before the arrival of security.
In this article, you will learn about how I booked window panes on my own in my store, located in the basement of a residential building.
A little theory at the beginning. The theory is not from Wikipedia, but in the form in which I understand it myself.
There are two types of armored glass: factory-made and armored with films. Unlike glasses armored with films, factory glasses received their armor at the production stage. With the help of armor films, you can protect any ordinary glass, such as shop windows or window glass. Of course, this glass can be broken. But this requires a lot of effort and time. So, for example, when hit with a hammer, the glass will not crumble into fragments, it will simply leave a small hole in it.
Films of various thicknesses are produced, as a rule, these are 100, 200 and 300 microns. The thicker the film, the higher the protection class. So, for example, for banks, halls of jewelry and weapons stores, the third class of protection is recommended. film thickness should be 600 µm. How is such a protection class achieved if the maximum film thickness is only 300 microns? You probably already guessed - one layer is glued to another.
For my purposes, I chose the 1st protection class: “protection against hooligans and vandals”, which corresponds to a film with a thickness of 300 microns. After searching the Internet for film sellers, I chose SOLARTEK film. The cost of 1 m2 - 500 rubles.
By the way, the same company can paste the film on the glass itself and it will cost 1040 rubles already. for 1m2.
So, let's move on to the process itself.
First of all, you need to remove the glass pane. Why not stick the film directly on the window, you ask? I didn't do it for the following reasons:
First, the glass must be thoroughly washed. It is more convenient to do this under the shower;
Secondly, it is more convenient to glue on a horizontal surface;
Thirdly, the edges of the film must be closed with glazing beads;
Fourthly, if you glue the film in winter, then this is necessary because. glass temperature must be at least 20 degrees
Dismantling of a double-glazed window
In order to remove a double-glazed window, you first need to remove the glazing beads holding it in the frame. This matter must be approached very seriously, because. you can easily scratch the window sash and the glazing beads themselves. To remove the glazing beads, I used an ax with a round sharp blade and a rubber mallet.
It is more convenient to start with long glazing beads, I started with the right one. Insert the blade of the ax between the frame and the glazing bead closer to the center.
Sometimes they are very close to each other that there is not even a gap. We hit the butt of the ax with a hammer several times so that the blade enters the slot. As soon as it has deepened a little, press on the butt with one hand, and with the other, take the ax handle and slowly turn it, trying to open the gap. Your goal is to open the gap so that after pulling out the blade, the glazing bead does not return to its place.
So by gradually moving the blade along the glazing bead, you increase the gap and at some point the glazing bead will pop out of engagement with the frame. Take it off.
Do the same with the opposite bead. Then move on to the top bead. After the top glazing bead is removed, carefully holding the glass from the inside, push it from the outside so that the top edge comes out of the frame. After that, take the glass from above with both hands and gently rock it from side to side, pull it out of the frame. Be careful, there are plastic mounting strips between the frame and glass on all sides - do not lose them.
After the glass is removed, the lower bead can be easily removed by hand.
Pay attention to the following:
It is necessary to mark the glazing beads so as not to confuse where they stood;
Remember the location of the mounting strips;
After the double-glazed window is removed, place it so that it does not fall
If you remove a double-glazed window not from a plastic window, but from a metal door, then the glazing beads are removed there much easier. Pick up the sealing gum that is between the glazing bead and the glass. Gently pull it out, and then remove the rest of the elastic bands. After that, the glazing beads can be easily removed without any tools.
Double-glazed window preparation
Before proceeding with gluing the film, it is necessary to thoroughly wash the double-glazed window. At work, I have a shower on the floor of which I laid rubber mats, and put a double-glazed window on top. Then you need to thoroughly wash the glass with soapy water.
After that, he drove water from the surface of the glass with a silicone scraper. On clean and dry glass, it is easy to see small growths, such as drops of paint or sealant.
Carefully remove them from the glass surface. To do this, you can use the blade of a clerical knife. Press the blade against the glass and use a scraper to clean its surface.
Looking ahead, I will say that most of the shortcomings that were visible on the reserved glass were associated with small debris that I did not notice at this stage.
After the glass is cleaned, it is recommended to degrease it, for example, with white spirit. I didn't do it. In addition, I washed the glass with an abrasive powder that is used to clean bathtubs. I know that theoretically this leaves small scratches on the glass, but such a powder well removes small imperceptible growths on the glass that are not visible to the eye. After that, I rinsed the glass well with water and dried it.
Film sticker
First you need to cut the film to the size of the glass. I marked and cut the film so that it did not reach the edges of the double-glazed window by 0.5 cm.
The film can be applied dry and wet. I didn’t even consider the dry method. I didn't have any experience with stickers. The essence of the wet application method is to moisten the glass before sticking the film. This will allow the film to move across the glass and prevent it from sticking immediately. As a solution, I used ordinary liquid soap, dissolving it in water in a ratio of 1 to 4, i.e. 25 gr. soap 100 gr. water. You can also use shampoo.
Moisten the glass liberally with a spray bottle.
Then remove the protective film from the adhesive layer.
Do not throw away the protective film - we will still need it. Carefully place the armor film on the double-glazed window and align its edges.
Press the film with your hand so that it does not move out, and begin to gradually expel water from under it. You need to expel from the center to the edges.
I armored 3 glasses and each time drove out the water in different ways - with a rag, a piece of plastic, a squeegee from a cartridge, a rubber spatula. I will not describe the disadvantages and advantages of each method. Now I will write the sequence of actions that I would use myself if I needed to glue the film again.
After you have placed the film on the glass and aligned the edges, smooth it out with your hand. This must be done so that the film sticks a little and does not move out. Then slightly moisten the film on top with soapy water, and then take the same protective film that was removed earlier and stick it on top. Then take a piece of plastic and use it to smooth the film from the center to the edges. I did not bother with small bubbles, but first glued the film over the entire area, expelling the bulk of the soapy water from under it. Then iron the film more carefully, trying to eliminate all small air bubbles under it.
Why is it necessary to glue the protective film on top? I came to this after gluing the first film scratched its entire surface. Despite the fact that the plastic was perfectly even, apparently microscopic irregularities still leave a mark on the armor film. To be honest, I do not understand why it is not protected by films on both sides.
You will also probably encounter the fact that the edges of the film will peel off from the double-glazed window.
This is due to the accumulation of soap solution on the edges of the glass, which prevents the film from sticking. You can temporarily fix the film with tape around the edges.
After the film is pasted, it needs to dry. The film should dry at a temperature not lower than 20 degrees for at least 24 hours.
I dried my double-glazed windows in the room for 5 hours, after which I installed them in the windows. When installing, do not forget to install the mounting strips as they were before.
Start installing the glazing beads in the reverse order - first short and then long. I started by installing the top glazing bead. Pressing the glazing bead with my hand with a hammer, I hammered it into place. The hammer must move along the plane of the glass. The glazing bead must be hammered evenly by tapping along its entire length so that it enters without distortions. If you are using an ordinary hammer, then be double careful not to break the glass and hit not directly on the glazing bead, but through a small wooden block. Long glazing beads are installed as follows. First, insert one end of the glazing bead into the corner of the frame. You can even knock on it from below so that it goes up as tightly as possible, then bend the glazing bead with your hand and bring the lower end into place. At this point, the bead will be slightly curved.
Gently tapping with a hammer in the middle of the glazing bead, hammer it into place.
Glass pane installed.
Result
In general, I am pleased with the result.
The first double-glazed window turned out to be the most unsuccessful, because. I glued it without a protective film, left a lot of small scratches and one big one.
The second and third double-glazed windows turned out without these shortcomings. But there are several points on them where the film did not stick due to a small speck.
Conclusion: wash the glass more thoroughly !!!
After I pasted the film in some places there were some muddy stains. Especially in those where I peeled off the film in the process and stuck it again.
After two days the stains were gone. Therefore, in the process of sticking the film, pay attention only to the specks that have fallen under the glass and to air bubbles. Everything else will disappear in a few days when the adhesive on the film is fully adhered to the glass.
I believe that the economic benefit from self-sticking the film is small - only 540 rubles. with m2. Would you like to glue the film yourself?
Sincerely, Vasily Devaev.
www.devaev.ru
It is easy to imagine the front line, even in the conditions of the modern "civilized" world. There are a lot of dangerous zones where you have to dodge bullets in this world. In such conditions, special assistance is required, which modern technologies are ready to offer. However, not only the sniper's bullet may require protection, but also in other cases when the need to dissipate the energy of movement becomes relevant. In any case, the idea of bulletproof glass seems like a good fit. Therefore, let's consider (just in case "fireman") what constitutes bulletproof, how other moments are produced.
Everyone once had to catch a ball flying fast in the air. The trick to this simple way of dissipating energy is when the hand moves along the motion vector of the flying object, gently stopping the flying ball.
This reduces the strength of the obstacle (arm). As a result, hitting the ball is perceived completely painless. In scientific terms, the force of the ball acting on the palm of the hand is equal to the moment of speed of movement.
The passage of a bullet through ordinary glass is inevitably accompanied by the destruction of the latter. Moreover, the bullet does not lose any energy of movement in this case of resistance However, unlike the palm of the hand, a piece of glass does not have the properties of synchronous movement. If a piece is fired from a firearm, it becomes obvious that this object is not able to bend and absorb energy.
As a result, the glass simply collapses, and the bullet overcomes the obstacle with virtually no loss of momentum. This is why ordinary glass is not capable of protecting against bullets, and in such cases, a bulletproof design is required that is more effective in terms of absorbing motion energy.
How bulletproof glass works
Ordinary and bulletproof glass are two completely different things. In any case, one design differs radically from the other. Meanwhile, bulletproof glass is not a completely bulletproof structure. Restrictions, of course, exist, as there are firearms with different recoil strengths.
This is what the structure of reinforced glass looks like, which is already difficult to destroy with bullets of a sufficiently large caliber fired from high-powered firearms Bulletproof glass is made up of several layers of durable transparent material with "interlayers" made on the basis of various types of plastics. Some designs of bulletproof glass contain a final inner layer made of polycarbonate (a hard type of plastic) or plastic film.
This layer prevents the "splint" effect (when pieces of glass or plastic break off when hit by a bullet). Such a "sandwich" of layers is called a laminate. A kind of bulletproof laminate is an order of magnitude thicker than ordinary glass, but at the same time it has a relatively small weight.
Energy absorbing design property
When a bullet hits bulletproof glass, it impacts the existing layers. Since the energy is distributed between the various layers of bulletproof glass and plastic interlayers, the spread of force occurs over a large area, which is accompanied by a rapid absorption of energy.
Effect on bulletproof glass of the simplest configuration, obtained from the impact of a bullet fired from a pistol at close range. As you can see in the picture, the structure was damaged, but did not collapse and did not miss the bullet. The movement of the bullet is slowed down to such a level of energy that the forces to overcome the obstacle are completely lost and are not able to cause significant damage. Bulletproof glass panels are, of course, damaged, but the plastic layers do not allow the panels to break into small fragments. Therefore, bulletproof glass should be considered rather as an energy-absorbing object in order to clearly understand the operation of this protective device.
How is bulletproof glass made?
The traditional execution of bulletproof glass, as already noted, is represented by alternating glass panels (3–10 mm thick) and plastic. In this case, the plastic is present in the form of a thin film (thickness 1-3 mm) made on the basis of polyvinyl butyral (PVB). Modern durable types of bulletproof glass represent a similar kind of "sandwich", containing:
- acrylic glass,
- ionoplastic polymer (for example, SentryGlas),
- ethylene vinyl acetate or polycarbonate.
In this case, thick layers of glass and plastic are separated by thinner films of various plastic materials, such as polyvinyl butyrol or polyurethane.
The structure of a three-layer structure from a number of first products: 1, 2 - ordinary glass; 3 - polyvinyl acetate resin mixed with polycarbonate glycol plasticizer To make a simple PVB-based bulletproof glass, a thin film of PVB is sandwiched between thicker glass to form a laminate. The formed laminate is heated and compressed until the plastic begins to melt, making it with a glass panel.
Typically, this process is done under vacuum to prevent air from getting in between the layers. The penetration of air into the interlayer contributes to the weakening of the laminate structure, affects the optical properties (distorts the transmitted light).
The device is then placed in an autoclave and brought to full readiness under conditions of higher temperature (150°C) and pressure (13-15 ATI). The main difficulty of this process is to ensure proper adhesion of the plastic and glass layers. It is necessary to remove air from the space between the layers, to exclude possible deformation of the plastic from overheating and overpressure.
Where is bulletproof glass used?
The product is manufactured in a variety of shapes and sizes to provide different levels of protection for emergency situations. Most often, the use of bulletproof glass is seen as a characteristic phenomenon in the banking sector.
Cash rooms are usually equipped with bulletproof ones, and bulletproof boxes for the exchange of documents and money are also used.
Protection of bank cash desks with a multilayer glass structure provides an increased level of security. This is one of those areas where bulletproof structures are used quite often. The quality of protection depends on the thickness of the product. The thicker the glass (the more layers), the better the absorption of energy is provided, respectively, the level of protection increases. The base bulletproof glass has a thickness of 30-40 mm, but if necessary, this parameter can be doubled.
The only problem is that increasing the thickness of the bulletproof glass inevitably leads to an increase in weight. Perhaps this is a minor problem for equipping a bank's cash desk, but becomes a significant problem, for example, in the case of the production of bulletproof glazing.
Increasing the thickness of the bulletproof glass also reduces the transparency factor as the light is "dimmed" by the additional layers of construction. Sometimes this design creates additional difficulties, for example, in a car, when bulletproof glass impairs the driver's visibility.
Bulletproof glass looks completely ordinary, but it does not break on impact, and if you shoot at it, then the bullet will not break through such glass, it will get stuck in it. It is impossible to make bulletproof glass yourself, as it is a complex industrial process, but it is very interesting to learn how it works.
Invention of bulletproof glass
The idea that it is possible to strengthen glass, making it bulletproof, came to the French scientist Edouard Benedictus in 1910. He came up with the idea of placing a celluloid film between two sheets of glass, which significantly increased the strength of the resulting product. Today, this method is called "laminating" glass, and Benedictus once called it "Triplex".
The same technology is currently used, but it has since improved significantly, and various types of polymers are used instead of celluloid. Sometimes curved glass is even glued this way. Bend them before joining.
Making bulletproof glass today
Bulletproof glass comes in various thicknesses, and it depends on this whether the glass will eventually stop the bullet. The thickness of such glasses is from 7 mm to 75 mm. Today, most often for the production of bulletproof glass, several layers of ordinary glass are used, between which layers of polycarbonate are poured. Polycarbonate is a clear plastic and is quite rigid, although it is layered. When a bullet penetrates the thickness of such glass, successive layers of polycarbonate absorb its energy, and it stops.
Currently, a special modification of bulletproof glass is being made - one-sided. A special type of plastic is used, the properties of which differ depending on the direction in which it is interacted with. One side of such glass stops bullets, but if you shoot from the other side of the glass, you can hit the enemy. This allows those behind the glass to be able to respond to an attack. At the same time, the glass surface is bent without collapsing.
Glass lamination
Laminating glass (applying a plastic film to it) is a very complex process from a technical point of view. They do it on automated equipment, in several stages. The last stage takes place at high temperature, the plastic film polymerizes and acquires approximately the same properties as stationery glue. It was at this time that the glasses finally connected.
While bulletproof glass is very strong, no glass is perfectly strong. The impact strength of triplex exceeds the strength of ordinary sheet glass by about 15 times. But even if such a sheet is destroyed, the fragments will remain on the film, and will not scatter in all directions, injuring people.
For production, three-layer bulletproof glass is considered ideal. The reason is that with each new layer, not only the protective properties increase, but also the cost of glass production. Laminated glass is used in extreme cases where there is a serious threat to human life or in museums to protect very expensive exhibits.
Nothing lasts forever, and even more so such a vulnerable part of the car as the windshield. The need to replace it often arises, and the funds for this do not appear with such constancy, so a convenient way to make a windshield is useful to any motorist.
You will need
- - Plexiglas 1.5 x 1.05 meters (for eight windshields);
- - paper according to the size of the windshield;
- - pencil;
- - scissors;
- - jigsaw;
- - basin with a lid;
- - water;
- - ropes.
Instruction
Buy a piece of organic glass from a hardware market or specialty store. Choose a larger area, approximately 1.5 x 1 meter. The area of such glass is enough for 8 windshields. Thus, this single cost will save you about $140 compared to ordering a new windshield for your car.
Take out your original windshield. Take paper and make a pattern that exactly matches the dimensions of the glass. Now transfer the pattern to the purchased plexiglass and cut out the desired piece. With the help of a jigsaw, this is done in 15 minutes in skilled hands.
Put water on the stove to boil in a large basin. Hold the glass by one side and dip into the basin when the water boils in it. To properly make a windshield, soak it in boiling water for a minute. Then make a deflection as far as the purchased plexiglass allows. Soak the bent piece in the water for 30 seconds, and then remove, controlling the safety of the deflection. If the desired camber angle is not reached, do not be discouraged, a slightly straight glass gives the impression of "tourist tuning".
Repeat these steps with the entire glass, alternately dipping different parts of the windshield into boiling water. If the water is not heated enough, barely noticeable cracks in the glass may appear. However, given the thickness of the glass and the size of the cracks, you can be sure that this defect will not be noticeable.
Pull the windshield to be made with ropes. This will allow you not to hold it, but to boil it safely in water for 5-6 minutes. For greater effect, close the basin with a lid. Correct dimensional inaccuracies due to temperature and physical force by filing the glass around the edges. Pull the elastic over the edge of the windshield. The made windshield is about 4mm thick, brand new and no scratches, no doubt will please your eye and wallet, put it in your car and enjoy the ride.
note
Make a paper pattern as accurately as possible according to the size of your native windshield, otherwise the result may be worse. If you don't heat the water enough, the glass may develop subtle cracks, which are smoothed out by the thickness of the glass.
Find a larger basin to make it as comfortable as possible to dip the glass.
