Such material as gypsum is actively used in the creation of building materials. Its most common use is to create an adhesive, which is commonly used for gluing drywall, gypsum-based panels and decorative gypsum parts. The article will make short review leading manufacturers of this product, as well as its advantages, disadvantages and features.

Peculiarities

Today there are many different building mixtures that allow gluing different materials. Many by such mixtures mean only cement or special tile adhesive, but the number of compounds and their types is much larger. Gypsum glue deserves special attention.

It is most often used in the following situations:

• When installing GWP and GVL, where the adhesive acts as the main binding material. These slabs are large and can be used to build partitions fairly quickly, so there is a need for an adhesive that sets quickly. In this case, gypsum glue is the main competitor of polyurethane foam.
• For wall cladding with gypsum tiles and artificial stone. Basically, gypsum glue is used for interior work.
• When you want to stick plasterboard / gypsum fiber sheets on walls or ceilings in the form of a rough finish, gypsum glue is the best fit.

Based on the scope of this binder, it is worth highlighting its main properties:

• hardens relatively quickly;
• affordable cost;
• characterized by good adhesion.

If we compare this type of glue with other types or cement, we can also identify disadvantages:

• The structure of the mixture after solidification is fragile, so it is not suitable for use under floor coverings.
• The glue is not characterized by moisture resistance and loses its properties upon contact with water, so it cannot be used for exterior decoration or in rooms with high humidity.

Glue is made relatively simply and quickly. It consists of gypsum and various additives that increase the strength of the substance in question.

The outer adhesive is a white or gray mixture in powder form.

This type of glue is used mainly for large-scale repairs. This leads to the fact that many manufacturers pack this material in large bags of 30 kilograms. It is almost impossible to find small packages, however, there are such.

Advantages

Gypsum mounting adhesive is characterized by many advantages:

• It is prepared easily and quickly.
• When kneading, lumps are practically not formed.
• Installation does not require the installation of a frame.
• Differs in the increased durability.

• Dries relatively quickly.
• It is spent sparingly, therefore, compared with conventional types of glue, which are inexpensive, the gypsum look pays off quickly enough.
• It is applied in a thin layer, so it saves floor space. In addition, this causes the previous advantage - material savings.
• Durability due to the addition of water-retaining additives to the composition.
• Cement mixtures require operational work, and the adhesive composition does not need to rush.
• It is possible to create a minimum thickness seam between blocks/slabs for cladding. For example, the manufacturer of gypsum glue Knauf guarantees that the wall will not freeze.

Types of gypsum glue

Mostly the gypsum composition is produced in the form of a dry powder. The presented variety of the mixture is very convenient to use. To increase the adhesion properties, special substances are added to the main components of the composition, which, in addition to increasing the binding properties, allow you to work with glue slowly.

If you are thinking about what to glue gypsum tiles on, then you should look at another type of gypsum composition, which includes quartz sand in the composition.

It is added in order to reduce the cost of production of the material. Expensive types of glue either do not have this sand at all, or it is present in them in small quantities.

It is important to note that the amount of additives affects the characteristics of the manufactured product.

The main task of such a composition is to create a strong adhesion to the surface. In the building materials market, you can find gypsum glue, which contains a large amount of gypsum. This affects the adhesion of the binder to the surface. You can also determine the quality of this product by the amount of water needed to prepare the adhesive. This amount can usually be read on the packaging. For example, if it is indicated that 300 ml of water is required for one kilogram of the composition, this indicates that a small amount of gypsum is present in the composition, which reduces its adhesive properties. When purchasing a similar adhesive material, you should be prepared for the fact that it can peel off during operation.

Manufacturers

There are a lot of companies that make gypsum mounting adhesive. We will consider the most famous of them, which are distinguished by good product quality:

Knauf

Produces gypsum glue in a package of 30 kilograms. The product from this manufacturer is the most popular product, as it has good German workmanship.

The disadvantages of the product in question include only the following parameters:

• relatively high cost, due to the fact that these are branded products with an advanced manufacturing formula.
• unstable quality, which is due to the fact that the company has 10 production facilities that also deal with gypsum glue. Due to the complexity of transportation, the product is shipped from the nearest factory, where the quality may be lower than in the central one. Some products received negative customer reviews.

As a leader from the manufacturer in question, it is worth highlighting the mounting gypsum adhesive - PEARLFIX.

VOLMA

An excellent Volgograd company that manufactures a high-quality gypsum product using a unique technology. Among builders, this manufacturer is characterized by an excellent reputation. Many construction companies use Volma boards and mixes. As noted earlier, it is extremely difficult to find gypsum glue in small packages, however, the manufacturer in question produces packages of five and 10 kg. Despite the presence of such packaging, it is problematic to find them on store shelves, since builders do not need such a volume, and private traders rarely purchase such goods. The advantages of the gypsum composition from the Volma company are high quality and affordable cost.

Gypsum polymer

A company that cooperates with KNAUF. The German company manufactures for him the constituent components for the creation of gypsum glue. It should be noted that the German company wants to include Gypsopolymer in the list of subsidiaries, but the Perm manufacturer still remains independent. Comparing with previous types of gypsum adhesive, it is important to note the relatively low cost, while the quality of the product does not suffer from this. It was the inexpensive price that became the main criterion for creating competition for previous brands.

Magma is also popular among buyers.

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Internal lining of surfaces with decorative gypsum tiles (gypsum stone), imitating natural materials (stone, brick, wood), is widespread due to a number of advantages of this material. Gypsum (alabaster, selenite) is environmentally friendly, safe, heat-resistant and easy to process.

The disadvantages of this material - hygroscopicity (accumulation of moisture from the environment), lack of moisture resistance and low impact resistance are overcome by impregnating the tiles with special hydrophobic compounds and using them for finishing rooms that are not used as industrial ones. But there is another condition for the successful operation of gypsum cladding - the right choice of tile adhesive.

Gypsum tiles are used for exterior cladding and interior decoration

Consider the types of adhesive mixtures used in the decoration of walls made of brick, concrete, stone and gypsum with decorative alabaster cladding, and how to use them, depending on the type of base.

Types of adhesives for plaster tiles

All types of gypsum tiles ready for laying have the same characteristics, except for geometric and artistic ones, so the choice of adhesive for mounting selenite depends on the type of base to be tiled and the amount of finishing work. Adhesives for alabaster cladding can be divided into the following groups:

1. Special mixtures based on gypsum.
2. Compositions suitable for laying selenite tiles.
3. Improvised materials used for the installation of gypsum stone.

Consider these groups of adhesive materials.

Gypsum based special adhesives

In order to glue gypsum stone on the most common types of base (brick, concrete, plaster, drywall), manufacturers of adhesives offer specialized mixtures, united in a group called "gypsum mounting adhesives".

Mounting adhesives

Mounting gypsum adhesive is a dry mixture of building alabaster and plasticizing additives, which is mixed with a certain amount of water and is used for mounting selenite tiles, as well as sealing cracks, seams, sinks and chips on a brick, stone and plastered surface.

Consider which glue is better, and what you need to pay attention to when buying it.

• Quartz sand content

The dry mix may contain white quartz sand, which is added by the manufacturer to reduce the cost of the material. The presence of this additive in the adhesive is necessarily indicated on the packaging of the material, and when choosing a composition, it is better to give preference to a mixture without sand or with minimal inclusion of it, since sand impairs adhesion.

• The ratio of the weight of the dry mixture and the amount of water necessary for its mixing

The degree of adhesion of gypsum adhesive depends on the percentage of alabaster in the mixture. The quality of the adhesive composition can be assessed by analyzing the required amount of water indicated on the package in the instructions for preparing the adhesive - at least 300 ml of water should be needed per 1 kg of dry mixture.

If less than 300 milliliters of water is required, then there is little gypsum in the glue, and there are a lot of cheaper additives.

• Setting time of the prepared glue

This indicator determines the duration of fixing the tile on the surface by hand after installing the product in place and, accordingly, the speed of finishing. The suitability of the solution in the bucket in time, depending on the manufacturer, ranges from 30 minutes to one hour. When choosing an adhesive, preference should be given to a material whose shelf life is as close as possible to half an hour. This will reduce the portions of the prepared mixture, but will allow you to glue the parts at a fast pace.

Preparation and use of gypsum-based adhesives

Instructions for preparing a mixture for laying alabaster tiles are available on the packaging of the material.

The measured amount of the dry mixture is gradually introduced with constant stirring into the required amount of water. If you do the opposite - pour water into the mixture, then when mixing, the formation of lumps is inevitable.

After reaching a homogeneous mass, the glue is allowed to stand for several minutes, then the composition is mixed again, after which the solution is ready for use.

Glue Alabaster on a gypsum basis - a specialized dry mix

Depending on the manufacturer, preparation methods may differ in the amount of water needed to mix a unit weight of the dry mix and the amount of time the mixed solution is held before remixing before use.

The surface to be faced (brick, concrete, plaster) must first be primed with a hydrophobic primer to retain moisture in the adhesive upon contact with them, and the brickwork seams must be rubbed with a leveling compound.

For laying gypsum tiles, glue is applied with a flat spatula to the base and back of the product, after which its excess is removed with a comb spatula. The tool, so that lumps of the hardened composition do not form on it, must be washed more often in water. The total thickness of the layers of the adhesive mixture after pressing the product at the installation site should not exceed one and a half centimeters.

Full strength is achieved by the mixture, as a rule, one day after the installation of the tile. The final drying time of the composition, depending on the manufacturer and the humidity in the room, can vary from four to seven days.

Adhesives suitable for laying selenite tiles

An alternative to special gypsum-based installation compounds are the following materials:

• adhesives for ceramic tiles;
• "liquid Nails".

Liquid nails for repair work

Consider the methods and expediency of using these tools when facing surfaces with alabaster.

Since gypsum cladding is not used for finishing rooms with difficult operating conditions, it is possible to glue alabaster parts on almost all types of glue for laying ceramics. The technology of using tile adhesives for sticking alabaster tiles does not differ from the methods of their use when facing with ceramics. If the surface is prepared correctly, gypsum tiles can even be laid on ready-made polymer adhesive mixtures.

It should be noted that tile laying mixtures have higher physical characteristics than selenite-based compositions. But in the case of facing with alabaster tiles, these materials do not have advantages over gypsum glue, their use is acceptable, but not advisable for the following reasons:

• when using glue for ceramics, the selenite lining must be primed, since gypsum, due to its hygroscopicity, will draw moisture from the glue necessary for curing;
• tile adhesive has a longer drying time than gypsum mixture;
• due to high characteristics, the price of adhesives for ceramics is higher, and their advantages remain unclaimed.

Adhesives for laying ceramic tiles

If you use a two-component epoxy-based mixture, then gypsum tiles can even be glued to a metal or plastic base, but for this you will have to reinforce the back surface of the alabaster products, which will greatly complicate the work. In addition, the high cost of strong and durable reactive compounds does not encourage their use when laying gypsum tiles, which they usually do not plan to use for a long time.

Installation of alabaster on "liquid nails"

This method of laying alabaster products is quite acceptable when finishing small areas of the surface and making spot repairs of gypsum lining. The glue is applied dotted or in the form of stripes on the back side of the tile, after which the part is kept for 10-15 minutes to dry the applied composition. Then the alabaster product is applied to the base to be lined in the design area and evenly pressed to the required level.

Fastening selenite finishes to bricks without first grouting the masonry joints is impractical due to the high consumption of glue.

"Liquid nails" provide a strong fastening of the tiles, without the need for professional skills. In addition, "liquid nails" is a ready-to-use adhesive that does not require any tool other than a mounting syringe to use. It is also convenient to glue parts on “liquid nails” because in the process there is almost no pollution of the finish and premises associated with the work.

The strength of liquid nails is quite significant

Liquid Nails is a safe and environmentally friendly material, but its cost per square footage of finish is high for medium to large jobs, so this cladding adhesive is not often used.

Use for gypsum finishing improvised means

Alabaster cladding can also be glued using non-traditional, non-glue building materials.

Building alabaster, closed in the right proportion with water, will successfully fix the tiles on brick, concrete and plaster. The surface to be trimmed must be preliminarily primed with an aqueous solution of latex in a ratio of 1:4. The white color of the mixture is convenient for laying tiles that are made independently and do not have artistic coloring. To increase the curing time of alabaster, you can add hardening retarders, also prepared by yourself, for example, a solution of glue or soap.

With paint putty, both leveling and finishing, you can also glue gypsum stone on drywall, brick, concrete and plaster. It is kneaded according to the instructions for leveling the surface, and then, with the help of spatulas, it is successfully used for mounting tiles. The mixture is applied in a continuous layer up to 10 mm thick on the back side of the product and leveled, after which the cladding part can be securely glued to the project site on the base.

Conclusion

The cost of most special gypsum-based adhesives is low, so choosing the cheapest one is unreasonable - the poor quality of the adhesive mixture will cause periodic drops and destruction of finishing elements, which may not be available for spot repairs.

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Sometimes in life there are situations when you definitely need to glue something. And there is no glue on hand. Or there are people who want to do everything with their own hands. In general, for everyone who wants to glue something, we post extensive material about glue and its types.

1. CLEATER
2. WOOD GLUE
3. ARABIC GUM
4. CASEIN GLUE
5. CELLULOID ADHESIVE
6. ADHESIVE FOR GLUING ORGANIC GLASS (PLEXI GLASS)
7. RUBBER GLUE
8. GLUE FOR STICKING BLOTH OR LEATHER ON TABLES
9. TISSUE PAPER GLUE
10. ADHESIVE FOR GLASS, PORCELAIN AND FAIENCE
11. GLUE FOR GLUING AMBER PRODUCTS
12. GLUE FOR GLUING IVORY PRODUCTS
13. LEATHER GLUE
14. GLUE FOR GLUING MARBLE PRODUCTS
15. GLUE FOR GLUING GYPSUM PRODUCTS
16. GLUE FOR BROKEN SHARDS
17. GLUE THE PIANO KEYS
18. GLUING MICA
19. UNIVERSAL CEMENT
20. UNIVERSAL GLUE BF-2
21. GLUE BF-6
22. HOMEMADE GLEEVARKA
23. HOW TO APPLY AN EVEN LAYER OF GLUE

PASTE

Dextrin glue. Dry potato starch is heated on an iron sheet to 400~. The resulting brown translucent lumps are broken into powder. Preparation of glue: 10 grams of this powder is carefully diluted in 2O-25 cubic centimeters of cold water. You can also add 2 grams of sugar. Glue is used mainly for gluing paper.

WOOD GLUE

Adhesive paste. For bonding to metal, glass, stone, etc. Finely sifted wood ash is added to hot wood glue to make a thick paste.

Binding glue. Glycerin is added to the melted wood glue (1 part by weight of glycerin to 20 parts by weight of glue).

Syndeticon. The composition of this glue: sugar 120 grams, slaked lime 30 grams, wood glue 120 grams and water 400 cubic centimeters. First, sugar is dissolved, then lime is added and heated, stirring, for an hour. The clear solution is drained and pieces of wood glue are added to it. When the glue swells, it is boiled as usual until the glue is completely dissolved. Syndeticone is a universal adhesive.

Waterproof adhesive. Natural drying oil or linseed oil is added to hot wood glue (1 part drying oil or oil to 4 parts glue).

ARABIC GUM

CASEIN GLUE

A few drops of formalin or a solution of aluminum alum are added to the finished casein glue to obtain a waterproof glue.

CELLULOID ADHESIVE

ADHESIVE FOR GLUING ORGANIC GLASS (PLEXI GLASS)

RUBBER GLUE

Another glue recipe for galoshes: 13 parts of gutta-percha and 25 parts of rubber are dissolved in 100 parts of carbon disulfide. 7-8 parts of bovine glue are added to the resulting solution and mixed. If the surfaces to be glued are cleaned (with a knife or sandpaper), then it is enough to put a thin layer of this glue so that the connection is very strong. The glue hardens completely after 1-2 days.

GLUE FOR STICKING BLOTH OR LEATHER ON TABLES

ADHESIVE FOR TISSUE PAPER

ADHESIVE FOR GLASS, PORCELAIN AND FAIENCE

Casein dissolved in liquid glass is also suitable for this purpose. Porcelain can be glued with the same compounds as glass. For repairing dishes, gypsum cement mixed with egg white is especially good. This cement hardens very quickly, and therefore must be handled with great care. You can get glue for porcelain and faience in the following way: Knock egg whites into foam and put them in a cool place for a day. After that, the settled protein should be separated and carefully ground with quicklime powder, adding it gradually in such an amount that a pasty mass is obtained. This glue is applied to the parts to be glued in a thin layer. The bonding process must be done as soon as possible so that the glue does not have time to dry. To glue parts of porcelain and glass objects, you can use the following lubricant: take washed glass flour (crushed glass) -1 part, add river sand (seeded) -2 parts and liquid glass -6 parts. This putty cements the parts to be glued very firmly. In structure, it is somewhat rough, so it is used for gluing large objects.

Here is another putty, which differs from the previous ones in a smaller structure, is also used for gluing large objects. They take burnt lime (quicklime) -1 part, chalk (ground) - 10 parts and liquid glass 2.5 parts. According to both recipes, the putty is prepared before use, as it quickly hardens. There is a particularly hard putty for gluing medium-sized objects made of glass and porcelain. It can be prepared as follows: burnt sculptural or medical plaster is taken and placed for one day in a saturated solution of alum. Then it is dried and again calcined and crushed. Gypsum treated in this way, in combination with water, turns into a very solid mass. The ratio of gypsum and water should be such that a liquid mass of cream consistency is obtained.

GLUE FOR GLUING AMBER PRODUCTS

ADHESIVE FOR GLUING IVORY PRODUCTS

LEATHER GLUE

ADHESIVE FOR GLUING MARBLE PRODUCTS

ADHESIVE FOR GLUING GYPSUM PRODUCTS

GLUE FOR BROKEN SHARDS

GLUING THE PIANO KEYS

GLUING MICA

UNIVERSAL CEMENT

UNIVERSAL GLUE BF-2

GLUE BF-6

HOMEMADE GLEEVARKA

HOW TO APPLY AN EVEN LAYER OF GLUE

Almost everyone faces the need for cosmetic repairs to their homes. At such moments, the main choice arises: entrust the work to professionals or do it yourself. For those who have chosen the second option, it will be very important to learn how to choose glue for plaster tiles. You will also need information on how to prepare the surface and how to install directly.

Criterias of choice

To determine the means that will help to securely attach the material to the surface, it is worth taking into account a number of factors. It is possible that the surface to be treated and the tile will need to be pre-primed with an impregnation, for example, based on acrylic. A special mixture of PVA glue with gypsum, various polymer mixtures, foam and putties of various compositions may also be suitable.

In order to guarantee a high bonding strength of the tiles to the surface, you need to choose an adhesive composition, taking into account the following points:

• what kind of work needs to be done;
• type of surface to be treated, including the degree of its porosity;
• the composition of the tile itself;
• type of masonry required.

Specifications

In modern stores there are cement mixtures or their analogues based on gypsum. Immediately before use, they must be diluted, following the instructions on the package. Reactive mixtures generally do not need to be mixed.

Dry mix is ​​used on those surfaces that have a screed or mineral base. Reactive mixtures are simply indispensable if you need to get the job done as quickly as possible.

Dry mixes for gluing

When choosing between a mixture of gypsum and cement-based, it is better to give preference to the first option. Tile is a porous material that quickly absorbs any moisture, because of this, the cement mixture will dry much longer.

To work, pour warm water into a container and pour the selected dry composition there. For better mixing, it is best to choose a construction mixer. The resulting mass hardens very quickly, so the gluing process must be carried out immediately.

If it is necessary to glue the tiles on a warm floor covering, additionally mix in Latexcol based on latex.

• Plusfix. A powdery mixture based on building cement and quartz sand. It also contains cellulose. Plusfix is ​​used to glue small tiles (maximum dimensions - 25x25 centimeters). The basis for laying tiles on such glue can serve as surfaces of cement, concrete and brick.
• Litokol K in its main characteristics it is very similar to Plusfix.
• You can also buy Litokol X11. The mixture contains Portland cement, as well as sand in the form of granules. Suitable for gluing large tiles.

• Perlfix- This is a mixture that is made from gypsum and building polymer additives. Perlfix has a minimum consumption of 1 square meter. Also among the advantages can be noted its environmental friendliness.
• Satyn PKG-28- This is a mixture based on gypsum, as well as mineral fillers. The composition also includes additives, thanks to which the composition is very plastic and fits perfectly on any surface.

• Dry white composition, which has a gypsum base, is "Gypsum". It sets fairly quickly and has a good grip. Excess can be easily and quickly removed - a rag moistened with plain water is suitable for this.
• Adhesive composition "Monte Alba" it is desirable to apply at internal works.

This adhesive is perfect for tiling with gypsum-based decorative tiles.

Liquid nails and dispersion compounds

Such products are suitable for high-quality tiling on drywall, and can also be used if the wall has been previously primed. Such compositions are quite expensive, but they can justifiably be called universal.

Ready-made formulations of such a brand as "LITOCOL".

It is necessary to use the mixture within eight hours from the moment of opening the package, since it hardens very quickly.

Among the varieties of the mixture can be distinguished:

• LITOACRIL PLUS This is a mixture in the form of a paste. It is based on acrylic. This composition is considered universal, has increased moisture resistance. Even if applied on a vertical surface, it will not drip. It dries quickly, which greatly speeds up the gluing work.
• LITOFLOOR K66- This is an adhesive that is used both for interior and exterior work. The composition is sufficiently resistant to low temperatures, as well as high humidity. Even if the surface has a lot of unevenness, LITOFLOOR K66 can provide good grip.
• Casco EXTREMFIX can be purchased as a liquid emulsion. Hardens very quickly. The result is visible after two hours. It is quite convenient if you use it in hard-to-reach places.

Reactive adhesive for gypsum tiles

Reactive agents are considered the most convenient to use - they have proven themselves excellently due to their versatility. They can be used for almost any type of tile. Also, the surface for laying can be different.

When working with gypsum material, it is advisable to use a reactive adhesive. In its composition, such an adhesive has only two components: the main one is the adhesive base, and the additional one is a hardener.

It is desirable to work with it extremely quickly - the mixture quickly hardens. At the same time, it is characterized by excellent elasticity - even if the surface has many irregularities, reactive glue can be used.

The following models of reactive glue are most popular:

• A composition that has a high-quality epoxy-polyurethane base is "Litoelastic". With it, you can glue the tiles on different kinds surfaces, for example, on concrete (including natural stone) and cement, it is convenient to work with it also on plywood and drywall. No shrinkage occurs after hardening. There are also no cracks. Suitable for vertical as well as horizontal surfaces. Resistant to sudden temperature changes. It has good grip on any surface. With it, you can carry out work even on the street.
• The universal tool is Litokol Epoxystuk, however, he is afraid of the impact chemical compositions with a fairly aggressive action. But this solution is distinguished by exceptional heat resistance.

• Suitable for indoor as well as all kinds of outdoor work LITOCHROM STARLIKE. The composition is not subject to the spread of mold, it is heat-resistant, chemical compounds with an aggressive environment are not afraid of it. Does not break down under the influence of ultraviolet radiation.
• You can buy a high quality mixture from an Italian company Epoxy Eco. It has a wide range of application at various temperatures, however, it should only be applied to a pre-primed surface.
• KERAPOXY MAPEI acid resistant. They can also rub the seams between the tiles. Has little water absorption. Even if the mixture has frozen, it can be easily soaked with plain warm water.

How to apply glue

A beautiful appearance, as well as a long service life of a tile, depends not only on the materials you have chosen - you should pay close attention to the work process itself. Finishing work must be carried out depending on the form of laying.

First, we prepare the necessary working equipment. First of all buy:

• construction tape measure;
• level;
• hand saw;
• simple pencil;
• a small ruler, a length of 1 meter will be enough;
• brush for applying glue;
• absorbent sponge;
• flexible spatula.

• clean the entire surface under the tile - remove all plaster, whitewash, paint, wallpaper and other old finishes;
• level the wall
• break the entire surface into horizontal zones that have a height of about 40 centimeters;
• apply the necessary markings on the surface of the wall;
• prime the surface with a primer and dry it thoroughly.

Make sure the surface is completely dry before applying the mixture directly.

Tiling should start from the corners- this will help correct any differences between the rows. With careful observance of the instructions, the mixture should not slip.

For information on how and how to glue gypsum tiles, see the following video.

Plaster Sculpture Cleaning

The increased porosity of untinted gypsum and its low resistance to abrasion severely limit the use of mechanical cleaning methods, especially with the use of aqueous detergents. The active water-absorbing capacity of the gypsum surface causes rapid absorption of moisture along with impurities into the pores of the material and its erosion. In addition, deep saturation of gypsum with water can cause damage to the reinforced sculpture (corrosion of metal and swelling of wooden frames), as well as dissolution of colored inclusions that are often present in the gypsum thickness and are brought to the surface as moisture evaporates. Limited use of detergents in combination with mechanical methods of cleaning is permissible only on a sculpture with an intact surface and a good preservation of the protective coating, which must be verified by moistening a small area of ​​the surface. In the absence of rapid absorption of the applied moisture (this indicates the protection of the pores), you can use the VEPOS or BIO-MIG preparation according to the method recommended for cleaning the stone.

In all other cases, especially when cleaning light sculptures, film cleaning methods should be preferred, eliminating mechanical friction and minimizing the use of water.

Film method for cleaning gypsum

One of these methods is the cleaning of gypsum using starch compresses, which is as follows. A paste is prepared from potato starch (to prepare 1 kg of paste, 930 g of distilled water and 70 g of dry starch are taken). The starch diluted in 100 g of cold water is added to the water brought to a boil and removed from the heat and mixed until a thick paste is formed. Cooled (up to 40-45 ° C) glue is ready for use.

The surface of the sculpture previously dedusted with a flute or vacuum cleaner is completely covered with the prepared solution in one step so that there are no halos on the border between the treated and untreated surface areas. The paste is applied with a flute, and in deep depressions with a brush. To obtain the desired coating thickness (0.4-0.5 cm), 2 applications with an interval of 10-15 minutes are usually required. A uniform layer of loosened cotton wool (1-1.5 cm) is carefully laid on the surface covered with paste, the purpose of which is to prevent the film from drying out and facilitate its subsequent removal.

After 6-10 hours, you should check the condition of the film by slightly unscrewing the edge of the compress. If the film has acquired sufficient elasticity and is easily removed, the compress can be removed. Otherwise, the exposure time is increased (this depends on the temperature and humidity of the air in the room). Especially care should be taken when the film dries out, as this involves the risk of detachment of the gypsum particles together with the removed film. If, however, drying could not be avoided, the film is steamed with hot water. If it is necessary to postpone the final part of the work for a day or more, you can protect the compress from drying out by covering the sculpture treated with a paste with a paper cover.

This cleaning method turned out to be extremely effective in the restoration of plaster medallions by the sculptor F. P. Tolstoy (ill. 32).

Gypsum gluing

Impregnation methods using dilute adhesive solutions, recommended for gluing porous stone, are also applicable to plaster sculpture. The only exceptions are some adhesives, such as the BF type, which leave intense yellow-brown halos on light plaster.

Usually, thermoplastics dissolved in organic solvents are used: PBMA, PVB and BMK-5 or aqueous solutions of PVA dispersion.

Before gluing the gypsum, it is important to completely remove all, even the smallest particles of gypsum (and sometimes hemp reinforcement fibers) present at the fracture points and preventing the exact alignment of the parts to be joined. Usually adhesive solutions are used with a more liquid consistency (15-20%) than for gluing porous stone, otherwise the methods for gluing gypsum and stone are no different (Fig. 33-34).

If you need to fill significant gaps between the connected fragments, it is appropriate to glue on a liquid gypsum mortar with the addition of 15-20% PVAD to the water intended for mixing the gypsum.

After connecting the fragments, the excess gypsum is squeezed out, and the fragments are fixed until the solution has completely set. Then, with a gypsum spatula or knife, excess gypsum protruding along the connecting seam is removed. If necessary, the dried seam is tinted under the general tone with watercolors with gouache or tempera white.

Restoration of losses and repair of chips on plaster

To restore losses in gypsum sculpture, the so-called pre-gypsum method has long been used, which consists in applying a gypsum solution to the damaged areas, from which the restored fragments are modeled.

Lost details of a complex configuration are usually first made in a soft material (for example, in white plasticine), and then the mold is removed from this model, on which the gypsum replacement is cast. The material for making the mold can be gypsum or, which is much more convenient, some synthetic elastic material - Sielast, Belast, Viksint, etc. (ill. 35-36).

The use of molds made of elastic materials greatly simplifies molding work, minimizes the complex and lengthy process of manufacturing a lumpy plaster mold, despite the necessity of additional fixation of such a mold with the help of an external plaster "casing".

Viksint is especially convenient in work (preferably an equal mixture of K-2 and U-1 compounds), hardened with the help of K-18 catalyst (4-5%). When applied to a molded object, the mass is well retained on a vertical plane and in 25-50 minutes, depending on the air temperature, it has time to completely harden. When casting replenishment with gypsum, this form does not require release lubrication, and only when making adhesive reinforcing additives to the gypsum mortar is it recommended to pre-lubricate the mold with a saturated soapy solution.

The molded part is attached to the sculpture with a gypsum mortar using the above gluing method. In some cases, when eliminating defects in hollow castings, the wall thickness is increased (“frozen”) from the inside with a gypsum mortar, shells, large cracks are filled, etc.

When working with a freshly prepared gypsum mortar, it should be taken into account that when it is applied to a dry gypsum surface, the newly applied gypsum is actively dehydrated, and as a result, its physical and mechanical properties change - adhesion to the surface worsens, color changes, density decreases sharply, etc.

Dehydration of the solution can be significantly reduced by abundantly saturating the surfaces to be re-gypsumed with water, or by isolating them with adhesive films (polyvinyl alcohol, starch, PVA dispersion, etc.).

In many cases, adhesive insulation is preferable to wetting, since the latter, as already noted, is highly undesirable for old gypsum products.

Dehydration can also be reduced by using more liquid gypsum than usual31, as well as by applying a somewhat "sagging" (thickened) solution. The most difficult thing is to exclude dehydration with the smallest additional plastering, which usually stand out on a light sculpture in a darker tone. In addition, due to their increased hardness, they are difficult to process. In such cases, instead of gypsum, it is more convenient to use gesso, prepared on polyvinyl glue with chalk.

Preparation of gesso

The starting material for the adhesive binder gesso is polyvinyl alcohol (PVA) - a product of the hydrolysis of polyvinyl acetate. It is a water-soluble white powder. To prepare the glue, it is necessary to soak 60 g of powder in 1 liter of distilled water and hold the mixture until it swells (about a day), and then finally dissolve until completely homogeneous in a water bath, stirring for 10-15 minutes. The prepared syrupy solution after cooling is ready for use.

As a filler, finely elutriated chalk is used, which is obtained by rubbing lump chalk through a fine sieve.

Chalk is poured into the glue in parts to the desired working consistency and the mixture is thoroughly mixed with a spatula. When determining the density of the mass, one must proceed from the size of the loss to be masticated: the smaller it is, the more liquid the batch should be.

The maximum thickness of mastics (up to 0.6 cm) can be obtained by multiple layer-by-layer build-up, not exceeding 0.2-0.3 cm in each layer. Before applying gesso, it is better to lubricate the chipped surface with PVA glue to increase the adhesion of mastics.

If it is necessary to tint the gesso to match the general tone of the sculpture, water-based dyes are used - watercolor, tea infusion, potassium permanganate solution, etc.

Gypsum tinting

It is not uncommon for soiled light-coloured plaster sculpture to be periodically whitewashed instead of being cleaned, in order to achieve a quick rejuvenation effect. However, such whites accumulate over time, smoothing and coarsening the finely modeled details of the sculpture. Therefore, gypsum tinting should be resorted to only in limited cases, for example: with low efficiency of the recommended cleaning methods, in the presence of non-removable stains or gypsum plasters and additions that stand out in tone.

When tinting a sculpture, the following rules must be observed:

1) the tinting composition should be applied evenly, possibly in a thinner layer that does not hide the smallest details of the modeling;

2) before proceeding to tinting, it is necessary to remove or thin out as much as possible all previous colorful layers;

3) in the presence of minor colored spots, it is enough to apply tinting locally, within the stain (“cosmetics”).

To tint light gypsum, it is best to use a liquid solution of finely grated gouache white on skim milk, tinted to the desired shade with watercolors.

Toning is carried out on a dry, fat-free surface with soft brushes and flutes or with the help of a paint sprayer, usually in several stages, with each layer drying.

Small colored spots that cannot be removed can be tinted to match the overall tone with a soft wax pastel. Tinting of small losses of the paint layer, as well as gypsum additions on a sculpture patinated in dark tones, is carried out with tempera or watercolor with tempera white (preferably acrylic).

The process of removing old shading is extremely difficult, since often the colorful crust is much stronger than the gypsum underneath. The use of paint softening compresses with warm water or solvents (selected depending on the paint binder - glue, oil or resin) is not always successful, and the work of removing paint with a scalpel almost inevitably leads to damage to the sculpted surface.

Gypsum hydrophobization

The porosity inherent in gypsum material, the presence of a highly developed inner surface, contributes to its increased tendency to deep moisture saturation, which can reach 25-30%. But even with a slight moistening of gypsum (up to 2-3%), the process of its structural destruction begins, leading to a decrease in strength and the appearance of plastic deformations ("creep" of gypsum).

According to the researchers, the mechanism of these modifications consists in the partial dissolution of the structure-forming elements of the gypsum material with water, as well as in the wedging action of water films that violate internal intercrystalline bonds.

Given these properties of the gypsum material, it becomes clear the importance attached to conservation protective measures aimed at increasing the moisture resistance of gypsum products. An important place among them belongs to various methods of hydrophobization of a gypsum surface in order to impart water-repellent properties to it.

We have already spoken about the wax coatings applied in the process of making sculptural castings. For this, 10-15% solutions of natural or artificial waxes in turpentine, white spirit and other solvents are usually used. This method of protecting gypsum, despite some of the drawbacks inherent in waxes (low resistance to abrasion and increased contamination), is generally justified - especially if wax coatings are restored and prevented in a timely manner. (In particular, the decorative purpose of wax coatings, which give the gypsum surface a characteristic warm tint and slight gloss, should be taken into account.)

As for organosilicon water repellents, which have a number of advantages over waxes, primarily durability, their use may be more preferable in the following cases:

1) if it is necessary to preserve the matte surface of the sculpture, which has not previously been subjected to protective treatment;

2) in the presence of hidden damage to the sculpture, chinks, additional gypsum, painted spots, etc., that can be detected during waxing;

3) when restoring wax coatings - as modifying additives (in the amount of 1-2%) to the applied waxes.

Of the organosilicon water repellents, 2-3% solutions of MCH-7 or K-921 in toluene or white spirit are more often used, since this group of products - polyorganosilazanes - along with the water-repellent ability, has strengthening properties.