How to make glue at home. Unique adhesive recipes. Traditional flour paste recipe

5. Protein adhesives In the second half of the 20th century. In construction, protein adhesives were widely used - flesh, bone and casein. They were also used in furniture production. In construction, these adhesives were used to prepare various painting compositions, including

A viscous mass of rubber glue, a fluid solution of “liquid glass”, solid slabs of wood glue – what do they have in common? The fact that they are all capable of forming a durable, thin film between the contacting surfaces of two pieces of identical or different materials. At the same time, the film not only has sufficient strength (cohesion, from the Latin “cohesus” - “connected”, “linked”), but also firmly adheres to the material being glued. (this is called adhesion - from the Latin “adhesio” - “sticking”).

Thousands of adhesives are now known, and the materials to be glued together are countless: metals, alloys, wood, plastics, ceramics, paper, fabrics, etc. Reliably connecting parts from different, often completely dissimilar materials is a complex technical problem, and in many cases solving it it is possible only with the help of glue, having specially selected not only its composition, but also the gluing method.

Nowadays, so many different adhesives have been invented and tested that they are used in literally all areas of the national economy, industry, and everyday life.

History of glue creation

The use of adhesives dates back as far as 1500 BC. e. , when the Egyptians used animal glue, acacia gum, eggs and liquid resins to veneer wooden objects. Animal glue-based plywood is used in various products discovered in Tibet dating back to 100 BC. e. In the palace of Knossos on the island. Cretan walls were painted with pigments, which were fixed with wet lime. To make papyrus, the plants were flattened and held together with flour paste to provide strength and shape to the final product.

According to biblical stories, during construction Tower of Babel bitumen was used as a binder; it was later used to putty on wooden cargo ships sailing in the Mediterranean. As Pliny notes, the Romanians putty their boats with pine tar and beeswax; Roman artisans used egg yolk to glue gold foil to paper. In Theophili, animal glues made from fish, horns and cheese were well known; bird glue - mistletoe extract was used by the Chinese to catch small birds.

In the 5th century AD e. Ravenna became the center of Byzantium and Eastern Italy, and fourteen centuries later one can still see the intricate mosaic designs of amazing beauty mounted on the ceilings of the famous mausoleum of Gallius Placidius.

Later, during the Renaissance, outstanding master artists used egg yolk as a pigment binder in paints.

Until the end of the last century, adhesives for common purposes were made mainly from materials of animal origin - casein or starch. But since adhesives based on them dissolve in water, the glued surfaces quickly came apart in a humid atmosphere.

Since 1920, many synthetic adhesives have appeared, which have found special application in a variety of industries ranging from plywood, cardboard, furniture and ticker tape gluing to wrapping and sealing. At home, they are used for gluing linoleum, plastic tiles, wooden beams or parquet floors, making putties, and preparing well-known wallpaper adhesives.

The enormous expansion of the adhesive industry, especially due to the increased use of synthetic resins, has led to the development of adhesives for bonding metal to metal and metal to wood.

Classification of adhesives

Adhesives can be organic or inorganic, synthetic or natural, the latter sometimes being produced by chemical or physical treatment.

Below is a brief classification of adhesives and substances that can be considered starting materials for the production of adhesives.

Natural adhesives

A) Animals

B) Vegetable

B) Mineral

Synthetic adhesives

A) Inorganic

B) Elastomeric

B) Thermoplastic (melting when heated)

D) Thermosetting (setting and hardening when heated)

Comparison table for synthetic adhesives

Name of glue composition purpose Precautions

Universal glue “Moment” Polychloroprene rubbers, resins, Ideal for gluing Flammable. Work should be carried out away from fire sources.

ethyl acetate, acetone, aliphatic wood, metal, leather, rubber, keep away from children.

and naphthalene hydrocarbons, felt, glass, ceramics, porcelain additives.

“Superglue” ethyl cyanoacrylate For repairing metal products, Caution! Cyanoacrylate!

rubber, wood, ceramics, glass, glue vapors should not be inhaled.

plastic, leather. Keep away from children. Bonds the skin of your hands in seconds.

PVA glue polyvinyl acetate For wood, paper, cardboard, The glue has passed the examination.

leather, photographs, glass, porcelain, linoleum.

Adhesive stick Does not contain solvents. For paper, cardboard, photographs and -

Silicate glue The composition is simpler For paper, cardboard. Avoid contact with eyes.

Basic principles for choosing adhesive

The choice of adhesive for various materials is determined by many conditions. It should be borne in mind that there is no universal glue that can glue any surface, but there is a huge number of different adhesives from which you need to choose the most suitable one.

One of the first and perhaps most important factors determining the choice of adhesive is the type and amount of stress that the adhesive joint must withstand during operation.

It should be borne in mind that the strength of the bond depends not only on the glue used, but also on the purpose of the connection, the gluing technique (i.e., the pressure applied), the condition of the surfaces being bonded, as well as on the strength and thickness of the parts that will be glued.

Despite the wide variety of materials to be bonded, adhesive systems must generally meet the following basic requirements.

1. For strong bonding, the surface must be cleaned of dust, dirt, oil stains, etc.

2. During the drying process, the adhesive film should not be overly compressed; the adhesive should always fill the unevenness at the joint.

3. The adhesive must be of optimum viscosity to mold to the rough surface.

4. With the exception of tacky adhesives (tape and film), they must cure when cold or heated to form a tough, durable bond.

5. The connection location must be chosen so that air and volatile solvents can easily evaporate. It must also be able to withstand the type and size of load it will subsequently be subjected to.

6. The adhesive joint must be resistant to bacteria and fungi and not shrink.

7. The adhesive film must be sufficiently resistant to surface fracture under the influence of tensile stress.

8. To ensure maximum adhesive strength, it is necessary correct selection glue for this type of material (chemical incompatibility of the glue and the surfaces to be bonded can lead to a decrease in the strength of the connection).

9. The adhesive should be used in the form of a liquid, the more viscous the thicker the film, since the latter can be weakened by air bubbles.

Natural adhesives

Animal glue

Used since ancient times, animal glues have always had great importance due to the variety of its properties and good adhesive ability. They can be used not only for gluing, but also for sizing and coating. There is always enough raw material for the production of animal glue - this is the skin, tissue and bones of animals, mainly cattle.

Animal glue is used as a hot liquid and forms a sticky film, which, after losing water, changes from a gelatinous to a hard, viscous, elastic state. Animal glues are made primarily from two sources - flesh (skin) and bones. They are soluble only in water and insoluble in organic solvents, oils and pure alcohol. The ability of animal adhesives to change from liquid to gel when cooled and from gel to liquid when heated has found application in bonding.

Receipt and use

Adhesives can be obtained in the form of sheets, slabs and granules, which are dissolved in water at 67 - 76.5 C and mechanical stirring. After dissolution (- 60 minutes), the temperature is reduced to the optimal value for effective use of glue (60 - 62.5 C). If animal glue is finely ground, then dissolution occurs under the same conditions within 1 minute.

The high effectiveness of animal glue is evidenced by its widespread use in the woodworking and furniture industries. To obtain a strong bond, it is important to follow these simple rules:

Apply a thin film of adhesive only to the surfaces to be glued;

Wait until the glue becomes viscous;

Apply pressure to squeeze out excess glue and bring the parts to be glued into close contact;

Maintain the glued parts under pressure until the initial bond strength is established (this usually requires 24 hours)

Animal glue is also widely used for the manufacture of compositions for sealing bottles, paper gaskets for protection against oil, air and oil, the production of matches, as well as matchboxes.

Isinglass

Unlike animal glue, fish glue has a low gelation point, which makes it possible to sell it in liquid form with a solid content of 40-50%. It is made from the scales of fish that do not contain oil, preferably like cod; From 1 ton of fish scales you can get approximately 150 liters of liquid fish glue. To prevent the decomposition of fish glue, it is recommended to add bactericidal preparations to it. Dried fish glue films are relatively fragile.

But fish glue is more resistant to solvents than animal glue. To improve glue penetration, alcohol or acetone is often added to the glued surfaces.

Application.

Fish glue is widely used in the production of shoe blanks, which are produced on high-speed gluing machines. Another important use of fish glue is in photoengraving work.

All of these above types of adhesives are used and have been manufactured these days. What did our ancestors use then? What they were good craftsmen written in many books. The famous ethnographer and researcher R. N. Maak wrote in 1854: “Traveling among the Yakuts, it is not difficult to see that they have a significant ability for a wide variety of crafts. Among the Yakuts there are skilled carpenters and copper and silver carvers.” In the 18th century, the Yakuts, who especially enjoyed the reputation of being good carpenters, were often hired for buildings in Okhotsk, Ayan and even Petropavlovsk. It turns out that in our time, some families still use fish bladder glues. The secret of making this glue has been passed down from generation to generation.

Many fish have a sac of air, called a swim bladder, located inside. This makes the fish lighter and more maneuverable.

To prepare fish glue, swim bladders of sturgeon fish (sturgeon, sterlet, etc.) are used. First, dry the bubbles well. After this, grind the bubbles to quickly obtain a homogeneous mass. Add water and cook over low heat, stirring constantly. The glue is used hot. The cooled residue can be used by heating to the desired consistency.

Household items that were made using this glue have survived and are in use today and are in excellent condition.

Conclusion

Having studied the history, classification, basic principles of choosing adhesives and comparing natural and synthetic adhesives, we came to the conclusion:

1. If it is necessary to use synthetic adhesives, it is very important to follow all precautions indicated on the packaging.

2. Natural adhesives do not contain chemical substances and therefore do not cause harm to health.

3. Using fish bladder glue, its quality has been proven by many years of experience of our ancestors.

1. PVA glue (polyvinyl acetate) glues wood, cardboard, glass, leather, fabric. The glue is applied in a thin layer to degreased surfaces, connected and compressed. The glue “sets” in 20 minutes. and dries completely in 24 hours. Before the adhesive joint dries, it is easy to clean it with a damp cloth.

2. Universal glue "Moment-1". glues wood, metal, rigid polyvinyl chloride, leather, rubber, felt, decorative laminated plastic, glass, ceramics. The glue is toxic and flammable, so you need to work with it in a well-ventilated area or outdoors - away from open flames. Apply a thin layer of glue to both surfaces to be glued (dry, cleaned and degreased), leave for 15 - 20 minutes until the glue dries until it “sticks” (that is, until the glue stops sticking to an applied clean finger), and squeeze them for a few seconds.
When gluing large-area surfaces made of flexible material, such as thin rubber and plastic, it is quite difficult to align the surfaces, since gluing occurs instantly and if applied incorrectly, it is almost impossible to change anything. Alignment is made easier by placing a blank sheet of paper between the surfaces to be glued. Gradually pushing out the paper, combine the surfaces and compress them (roll them). It is convenient to apply glue to large surfaces with a metal spatula.

3. Epoxy adhesive is intended for gluing metal, ceramics, glass, wood and other materials, for sealing holes and cracks, and can also be used as a varnish coating. The glue is water and oil resistant and is a good electrical insulator.
The prepared glue, as well as its components, have an irritating effect on the skin. Any glue that gets on your skin should be washed off immediately with warm water and soap. Glue should not be used to repair food utensils.
The glue is prepared immediately before use by mixing the resin with the hardener in the ratio specified in the instructions (often 10:1). The components are thoroughly mixed for 5 - 10 minutes. The surfaces to be glued are covered with a thin layer of glue and connected with slight pressure. Excess glue is removed, and this can be done immediately or after 4 - 5 hours, when partial polymerization of the glue has already occurred and excess glue can be easily removed with a knife or other suitable tool. Full cure at room temperature occurs within a day. At lower temperatures, curing time increases significantly. The strength of the adhesive joint can be increased by heating the parts to be glued at a temperature of about 100 °C for several hours of glue curing. Strength significantly depends on the accuracy of compliance with the ratio of mixed components specified in the instructions. The resin for commercially available epoxy adhesive usually already contains a plasticizer that provides the necessary elasticity of the adhesive joint. If you prepare the glue yourself, you must add up to 10% plasticizer to the resin before adding the hardener and mix thoroughly. Dibutyl phthalate is most often used as a plasticizer. The hardener is polyethylene polyamine.

4. Adhesives BF-2 and BF-4 glue metals, plastics, wood, glass, ceramics, leather, and are characterized by good electrical insulating properties, but high dielectric losses (tgb = 0.05). BF-2 glue is used when good moisture and heat resistance of the adhesive joint is required. BF-4 glue is preferred if elasticity and frost resistance of the joint are required. To achieve high joint strength, the bonded surfaces must be carefully adjusted to each other (the gap is no more than 0.05 mm), cleaned of dirt and oxides, and degreased with acetone or another solvent. A thin primer layer of glue is applied to the surfaces prepared in this way with a brush, air-dried for about 1 hour or for 15 minutes. at a temperature of 85 - 95 °C. After cooling the parts to room temperature, apply a second layer of glue, allow it to dry, after which the parts are pulled together (for example, with a clamp) and placed in a thermostat or oven, where they are dried at a temperature of 120 - 160 °C for 2 hours. If the parts have low heat resistance, the adhesive joint is dried at room temperature for 36 - 48 hours, but the adhesive strength in this case will be lower.
These adhesives can be used to protect metal parts from corrosion. They spread well over the metal surface and provide a coating that is sufficiently resistant to mechanical and chemical influences. If the glue is too thick, it can be diluted with ethyl alcohol.

5. BF-6 adhesives are used for gluing fabrics, providing strength no less than when sewing. To make the connection invisible, trim the fringe and adjust the edges of the fabric. Then cut out an overlay 1.5 - 2 cm wide from a similar or thinner fabric. The fabric is cleaned of dust and dirt. To prevent the glue from sticking out on the front side of the fabric in the future, the lining and the joint are generously moistened with water and wrung out. Using a brush, apply a thin layer of glue from the underside of the fabric and onto the glued side of the lining. Allow the glue to air dry until tack-free, then apply a second layer and also dry it until tack-free. Apply the pad from the inside out, cover it with a clean damp cloth and press it with a hot iron. Every 10 - 12 seconds, the iron is torn off for 2 - 3 seconds, then pressed again. This operation is repeated until the moistened area of ​​the fabric is dry. Then, without moving the material, allow it to cool to room temperature. The iron should be heated to the temperature recommended for this type of fabric. In a similar way, you can seal a tear, cut, or eliminate a hole in the fabric.

6. Adhesives 88H are good at gluing rubber and other materials to metal. The glue is diluted with benzene to the consistency of liquid sour cream (it does not stretch behind the brush and does not flow from it), spread it on rubber (or other material) and dry for 3 - 5 minutes. Then the second layer is applied to the rubber and the first to the metal. Both layers are dried for 5 - 6 minutes. The parts are connected and the rubber is rolled with a roller and dried for 24 hours (preferably under a press).

7. Unicum glue provides a waterproof connection of products made of wood, metal, rubber, ceramics, leather, artificial leather, dense fabrics, foam rubber and plastics in various combinations. A layer of glue is applied to the surfaces to be glued, degreased with acetone or gasoline, after 2 - 3 minutes - another layer and compressed tightly for 5 - 6 hours. It is recommended to use glued products no earlier than after 24 hours. It is necessary to work with glue in a well-ventilated area away from fire, since the glue is flammable.

8. "Mars" glue is intended mainly for gluing leather and leatherette products, but can also be successfully used for ceramics, wood, cardboard, and polystyrene. A thin layer of glue is applied to dry and clean surfaces. After 5 minutes, apply the second layer, connect the bonded surfaces and leave under load for 24 hours. The glue is flammable, and you need to work with it away from open fire.

9. Isocyanate glue provides a strong connection between rubber and metal. Glue composition: leuconate and dichloroethane in a proportion of 2:8. The parts are cleaned and degreased. The metal is coated with glue and air dried for 30 - 40 minutes. Then the first layer is applied to the rubber, and the second layer to the metal. After 20 - 30 minutes, a third layer is applied to the metal, and a second layer to the rubber. The parts are connected, compressed, heated to a temperature of 180 - 240 °C and dried at this temperature for 10 - 12 minutes.

10. Wood glue is widely used for gluing wood. The quality of the glue largely depends on the correctness of its preparation. The required amount of dry tile adhesive is crushed, poured with clean cold water (3 - 5 cm above the glue level) and kept in it for 6 - 12 hours. After the glue has swollen, the top layer of water is drained, the container with the glue is placed in a “water bath”, and heated over low heat, stirring occasionally, until all the pieces of glue have dissolved. During the preparation process, the temperature of the glue should not exceed 60 - 70 °C, otherwise its adhesive ability will deteriorate. During the gluing process, the temperature of the adhesive solution should be 30 - 50 °C.
When gluing wood along the grain, the surfaces of the parts are coated with glue once, the end surfaces - twice, allowing the first layer to dry. The parts to be glued are not compressed immediately, since the hot glue is partially squeezed out, but the glue is allowed to dry for 3 - 5 minutes (the film should be sticky when tested with your finger and stretch into threads). After this, the parts are connected, rubbed in a little, moving them slightly, then squeezed (with a vice, clamps) or tied (with twine, bandage) and left for 4 - 6 hours. When repairing products, the layer of previous glue is removed. To do this, moisten a rag with water and place it on the layer of glue for 2 hours. The softened glue is scraped off with a knife, chisel or spatula.
The strength of the adhesive joint depends on its thickness and the moisture content of the wood. To obtain a strong connection, the thickness of the seam should be no more than 0.1 - 0.15 mm. When wood moisture content is more than 12% (veneer - 5%), the bonding strength deteriorates significantly. A small addition of an antiseptic (borax, phenol, salicylic acid) makes the glue resistant to all types of mold.

11. Waterproof carpenter's glue can be obtained by adding natural alifa to regular carpenter's glue in a mass ratio of 4:1.

12. Adhesive paste is used for priming, puttying and gluing wood parts whose joint gaps exceed 0.2 mm. The paste is obtained by mixing finely sifted ash, or dry sifted chalk, or micanite dust, etc. in hot glue. Glue paste can also be obtained by mixing the above fillers with other adhesives.

13. Syndeticone glue is used for gluing wood and gluing various materials to it.
Glue composition (in grams per liter of water): dry wood glue - 200, sugar - 200, slaked lime - 70. Dissolve sugar in water, then lime and heat over low heat until a clear liquid is obtained. The solution is filtered and crushed wood glue is added to it. The wood glue is allowed to swell for 24 hours, and then it is dissolved in a glue maker in a “water bath.” The glue can be stored in a closed glass container. long time without losing its properties.
When finely sifted ash or dry chalk is added to the glue, a good putty paste is obtained.

14. Casein glue is used for gluing wood, mainly with pressing, cardboard, as well as for gluing paper, fabric, and leather to wood and cardboard. Casein is a light powder, diluted in cold water until the sour cream becomes thick, adding water in small portions and stirring thoroughly for 40 - 50 minutes. The glue is ready for use in an hour and a half. Apply the glue with a brush to both surfaces to be glued, which after 4 - 6 minutes are tightly compressed and kept for at least 6 - 8 hours. Complete drying will occur in 18 - 20 hours.
Dried glue is much more resistant to high temperature and humidity than wood glue. The addition of aluminum alum (100 g/l) makes the adhesive joint more water-resistant. The glue must be antiseptic, otherwise when hygroscopic materials dry slowly, mold will form and the parts may be damaged. For antiseptic use, the glue is diluted in a 10 - 15% ammonia solution (ammonia) or 200 g/l of borax is added to it. It should be remembered that glue leaves stains, especially noticeable on light wood, and over time these stains may become more contrasting.
Over-sitting (more than 4 - 6 hours) and thickened glue should not be diluted with water: it has lost its adhesive ability.
15. Bookbinding glue is prepared from carpentry glue by adding glycerin (1/20 of the glue volume) to liquid hot glue (directly in a “water bath”).

16. Glue for cardboard is prepared by dissolving 9 g in 100 ml of water. office (silicate) glue, 6 g. potato starch and 1 gr. Sahara. The resulting slurry is heated until a homogeneous mass is formed. You can glue cardboard with many other glues, but glue according to this recipe gives a stronger connection than, for example, flour paste, and is also cheaper than many other glues, which is important when glue consumption is high.

17. Dextrin glue is a common glue for paper. Prepare glue by diluting dextrin with cold water (400 g/l). You can prepare dextrin yourself by heating dry potato starch on an iron sheet to 400 °C and grinding the resulting brown opaque lumps into powder.

18. Tissue paper glue can be prepared by adding enough denatured alcohol to dextrin glue to make a syrupy liquid. This glue does not bleed through the paper.

19. Gum arabic - glue for paper and cardboard made from gum (thickened juice of some fruit trees, for example cherries, plums, apricots). The gum is crushed into powder and diluted with warm water to the consistency of liquid sour cream.

20. Starch paste - glue for paper. Potato starch at a rate of 60 - 80 g/l is dissolved in cold water (1/5 of the total volume of water), stirred thoroughly, brewed with boiling water (4/5 of the total volume of water) and borax (25 g/l) is added. The paste is usually used cold.

21. Flour paste - glue for paper and cardboard. To prepare 1 liter. For paste, take 200 g of wheat flour and 50 g of dry wood glue. The flour is diluted in cold water and boiling water is added while thoroughly stirring until a liquid slurry forms. Then pour in wood glue dissolved in water. Cook the resulting mass over low heat, stirring continuously so that it does not burn. When the paste begins to bubble and turns bluish, the paste is ready.

22. Photo glue can be used for gluing scales and nameplates made on photo paper. Composition of photo glue (in grams per liter of water): starch - 60, aluminum alum - 40, chalk (tooth powder) - 40, dry blue - 1. About half of the total amount of water is heated and alum is dissolved in it. The remaining water is used to prepare a starch paste. The alum solution is poured into the paste and stirred well. After half an hour, add chalk (tooth powder) and blue and mix thoroughly. Store glue in a closed glass container.

23. Glue for joining fabric, dermantine and leather with wood can be prepared according to next recipe(in mass fractions): mix wheat flour (40), rosin (3), aluminum alum (1.5), add water (100) and mix thoroughly. The resulting doughy mass is placed on low heat and stirred until the mass begins to thicken. Gluing is done with hot glue.

24. Protacryl - plastic mass - universal high-quality adhesive and coating, which after sanding and polishing gives a decorative moisture-proof surface. Widely used in dental practice. It is insoluble in acids, alkalis, mineral oils, and adheres well to various materials- metal, glass, porcelain, plastic, wood.
Protacryl consists of powder and liquid, which are mixed immediately before use in a ratio of 2: (1 - 1.1) in a glass or porcelain container and stirred for 1 - 2 minutes. At the same time, avoid getting air bubbles into the mass (the spatula should always touch the bottom of the dish when stirring the mass). The powder should be completely saturated with liquid, the surface of the mass should become uniform and shiny. The readiness of the mass is determined by the appearance of threads trailing behind the spatula. The surfaces to be bonded are cleaned of dirt and thoroughly degreased with acetone, gasoline or some other organic solvent.
Apply glue to both surfaces, then combine them and lightly compress. Complete polymerization at a temperature of 40 - 45 C occurs after 15 - 20 minutes, at room temperature - after 30 - 70 minutes.
To achieve the required coating thickness, protacryl can be applied to the surface in several layers. Places not to be coated are lubricated with silicone oil or rubbed with graphite powder. Ordinary sunflower oil gives slightly worse results.

25. Celluloid glue is a solution of celluloid in acetone. To prepare such glue at home, you need to dissolve pieces of celluloid (2 - 3 g) in acetone (100 ml). The glue is applied to the grease-free surface with a brush or wooden spatula, allowed to dry for 2 - 3 minutes, after which the parts are tightly connected and dried at room temperature for about an hour.

26. Glue for polystyrene - a solution of polystyrene shavings (4 - 6 g) in benzene (10 ml). The gluing technology is the same as for celluloid, but the drying time is 10 - 12 hours. You can also glue polystyrene parts with pure acetone, which dissolves this material well. In addition, Unicum or Mars glue is used.

27. Glue for organic glass can have one of the following compositions (solution of organic glass shavings):
0.5 - 1.5 g chips, 100 ml dichloroethane.
3 - 5 g of chips, 100 ml of 85% formic acid.
3 - 5 g of shavings, 100 ml of glacial acetic acid.
0.5 - 1 g of shavings, a mixture of acetone (60 ml) and vinegar essence (40 ml).
In addition, organic glass can be glued with pure dichloroethane. To do this, it is applied to organic glass with a brush until the surface layer of the parts begins to dissolve slightly. It is better to work with dichloroethane outdoors, as it is toxic. You should avoid getting it on damaged areas of the skin.>

28. Glue for ebonite is prepared by mixing pure rosin powder (6 parts by mass) with linseed oil (1 part). The composition is heated, stirring, and brought to a boil. After cooling, the glue remains indefinitely. The surfaces to be glued are treated with a rasp, heated at a temperature of 50 - 70 °C for 15 - 20 minutes and glue heated to a boil is applied to them.

29. An adhesive solution of polystyrene foam in dichloroethane or acetone is resistant to alkali and alkaline electrolyte and can serve as a protective film for a painted surface. The solution is prepared in a clean glass container by pouring the solvent into small pieces of foam. The solution should have the thickness of silicate glue. Apply a thin layer of solution to a degreased surface with pure gasoline or acetone and dry it with a brush and dry it. Then the surface is covered with paint or bitumen varnish and, after drying, the solution is applied again. As a result, a layer of paint or varnish will appear between two layers of alkali-resistant coating. This method is good for coating, for example, alkaline battery banks. The solution is toxic and volatile. It is necessary to prepare the solution and work with it outdoors or in a room with good ventilation. The solution should be stored in a container with a ground stopper.

30. Glass glue is prepared by dissolving gelatin in an equal amount of 5% solution of potassium dichromate. The glue is prepared in a darkened room. The parts are coated, tightened with a clamp or, for example, tightly wrapped with threads and kept in the light for 5 - 8 hours. The glue does not dissolve in hot water.

31. Adhesive for glass and ceramics can have one of the following compositions:
A solution of casein in liquid glass (or silicate glue).
Gypsum mixed with egg white.
Gypsum soaked for a day in a saturated solution of aluminum alum, then dried, ground and mixed with water (this best composition for gluing ceramics).
A solution of dry finely ground chalk (tooth powder) in liquid glass in a ratio of 1:4 (by weight).
All these glues should have the consistency of sour cream.

32. Paste for gluing glass to metal is convenient for large areas of bonded surfaces, as it has a liquid consistency. The adhesive connection is quite strong. Composition of the paste in mass fractions:
Midi oxide - 2.
Emery powder - 2.
Liquid glass - 6.
The mixture is ground until a homogeneous mass is formed. The glued parts are heated to 100 °C and maintained at this temperature for 2 hours, then cooled to room temperature. After 12 - 14 hours the paste will completely harden.

33. Heat-resistant adhesive paste is suitable for repairing vitrified resistors, for insulating their leads, as well as for insulating heating elements. Dried talc (6 parts by mass) is mixed with liquid glass(or silicate glue), which is taken enough to get a mass of sour cream consistency (approximately 8 - 12 parts). Damaged or moldable areas of the coating are coated with paste and dried at room temperature for about an hour. Then the part is heated to 100 - 110 °C and kept at temperature for 10 - 15 minutes.

34. Putty for fastening steel reinforcement in stone can be prepared according to the following recipe in (mass fractions:
Mix the dry ingredients - iron filings (100), gypsum (300), ammonia (5) and dilute this mixture with 9% so-called table vinegar (40 - 60) to the desired consistency. The resulting putty is used immediately.

35. Locking putty prevents spontaneous unscrewing of nuts, replacing various locking washers. Talc is mixed in nitro enamel in a ratio of 1:3 and diluted to the desired consistency with acetone or solvent for nitro paints.

36. Putties are used to fill minor flaws and level the surface of metal, wood and plastic products before applying decorative paint and varnish coatings.
Select putty from the table depending on the material of the product, the condition of its surface and the paint coating that will be applied.