Lesson on technology on the topic "technologies of housekeeping". TTK. Treatment of surfaces for painting with aqueous and non-aqueous compounds. Partial greasing on top Preparing wood and stone walls

In order to master the specified type of professional activity and the relevant professional competencies, the student, in the course of mastering Section 4 PM. 04 "Repair of painted and glued surfaces, should:

have practical experience:

repair of painted and pasted surfaces

be able to:

repair glued surfaces with wallpaper and films

repair painted surfaces with various paint compositions

control the quality of repairs

follow safe conditions labor

know:

technology for repairing surfaces pasted over various materials, dyed with water and not water compositions

requirements sanitary norms and rules for the repair of glued and painted surfaces

safety regulations for repair work

In this section for independent work it is proposed:

Topic 4.2. Technology of repair of painted and glued surfaces.

1. Drawing up technological maps:

For the repair of painted surfaces with water compositions;

For the repair of painted surfaces with non-aqueous compounds;

For the repair of wallpapered surfaces.

criteria for evaluation.

An important part independent work student is the preparation and defense of abstracts, reports, projects, essays, tests and term papers.

Types of independent work in the study of any discipline are the preparation of a report, abstract, messages or abstract. These works are written works.

1. report – is a verbal or written presentation of a message to a specific

The report is compiled according to the following algorithm:

Select literature on the topic, get acquainted with its content.

Using bookmarks, mark the most significant places or make

Plan the report.

Write a report plan, in the conclusion of which it is necessary to express your

relation to the topic and its content.

Prepare in accordance with the requirements for the design of written work.

Approximate report structure:

1. Title page

2. Explanatory note

3. Introduction

4. Text of the work

5. Conclusion.

3. List of used literature.

Abstract (from the Latin refero - I report, inform), a summary in writing or in the form of a public presentation of the content of the book, scientific work, the results of the study of a scientific problem; a report on a specific topic, including a review of relevant literature and other sources. As a rule, the abstract has a scientific - informational purpose.

In the process of working on an abstract, 4 stages can be distinguished:

Introductory - choosing a topic, working on a plan and introduction.

The main one is work on the content and conclusion of the abstract.

The final one is the design of the abstract.

Abstract defense (at an exam, student conference, etc.)

Abstract structure:

Title page

Introduction: substantiation of the topic of the abstract, its relevance, significance; enumeration of the issues considered in the abstract; definition of goals and objectives of the work; review of sources and literature. Its volume is 1-3 pages.

Main part: the main part has a title that expresses the essence of the abstract, may consist of two or three sections, which also have a title. In the main part, the state of the issue under study is deeply and systematized; conflicting opinions contained in various sources are given, which are analyzed and evaluated with particular care.

• Conclusion ( conclusions and suggestions): the results of the analysis of the evolution and development trends of the issue under consideration are formulated; proposals are made on ways to resolve significant issues.

The volume of the conclusion is 2-3 pages.

When presenting the material, the following rules must be observed:

It is not recommended to narrate in the first person singular. You need to choose the impersonal forms of the verb. For example, instead of the phrase "I conducted an experiment", it is better to write "an experiment".

When mentioning surnames in the text, be sure to put initials before the surname.

The quotation is given in the form in which it is given in the source and is enclosed in quotation marks on both sides.

Each chapter starts on a new page.

3. Synopsis - this is a consistent, coherent presentation of the material of a book or article in accordance with its logical structure. The main part of the abstract is made up of theses, but evidence, facts and extracts, diagrams and tables, as well as the reader's own notes about what they have read are added to them. If the abstract consists of only extracts, it is called textual abstract. This is the most “non-developing” type of abstract, since when compiling it, the student’s thought is practically turned off from the work, and the whole thing comes down to mechanical rewriting of the text. If the content of the reading is presented mainly in the form of presentation, retelling is free abstract. If from what is read, only one or a few problems related to the topic stand out as the main ones, but not all of the content of the book is a thematic summary.

The situation is especially special with the preparation for painting of previously painted surfaces during the repair of buildings. Before proceeding with the preparation of such surfaces for painting, it is necessary to establish the reasons why the painting has become unusable, and take measures to eliminate these reasons, if they are associated with the faulty state of building structures.

Major damage to existing paintwork includes:

• color change, usually expressed in lightening, "fading" under the influence of daylight;
• airborne dust and soot pollution;
• "efflorescence" - traces of soluble salts that have appeared on the surface of the painting, appearing as a result of either delayed drying or periodic wetting of the surface, if such salts are present in the thickness of the structures;
• local contamination by products contained in the thickness of the structure, observed mainly on the painted plaster in the area smoke channels located in the brickwork, as well as from contact with various subjects and due to temporary moisture;
• the presence of a network of shrinkage cracks, which are the result of either incorrect drawing up of painting compositions, or the influence of atmospheric influences;
• "shallowing" of water-based paints, which is the result of either an insufficient amount of binder in paint compositions, or improper work, or destruction of the binder under the influence of atmospheric influences;
• delamination of paint layers under the influence of atmospheric influences, or insufficient strength of the bases on which the painting was made, or due to improper work, which consists in painting on a contaminated or insufficiently dried base.

Preparation for painting with aqueous compositions of surfaces previously painted with the same compositions must be carried out in compliance with certain rules.

Insignificant thick layers of old paint should be removed only in cases where the connection with the base of these layers is broken, as well as in case of excessive contamination with soot and dust. Significantly thick nabel should be removed in all cases, since they cannot serve solid foundation for a new color.

Removal of a thin layer of adhesive coloring can be done by rinsing warm water, and lime, casein, silicate and multi-layer adhesive color - mechanized way with preliminary wetting of the removed coloring with water. After such removal, the plaster is ground lime mortar with fine sand.

To remove stains on glue coloring a strong vitriol primer is used. For other water-based paints, as well as when the use of a vitriol primer is insufficient, the pre-washed and dried surface is covered with zinc oil white diluted in turpentine or rosin varnish. In case of large pollution that cannot be eliminated in this way, it is advisable to replace the plaster with damaged area surfaces.

If surfaces are to be painted with compositions that differ from the previous ones, then the cleaning of old nabels should be carried out in all cases, regardless of the state of these nabels.
When painting with compositions based on especially strong binders, such as casein glue, liquid glass, perchlorvinyl varnish, old nabes should be completely removed, and weak plaster should be replaced with a new one.

If surfaces are painted previously painted with oil and other non-aqueous formulations, then the old color is removed only if the connection between the paint layer and the base is weakened, when there is a large number of cracks and color lags behind the surface.

The remaining contaminated surfaces are washed with warm water and soap, and in case of significant contamination with turpentine, kerosene, thinner gasoline (white spirit) or other solvents.

Removing old oil paint is often very difficult. Only if the paint has a very low strength can it be cleaned with a scraper, a steel spatula or a chisel! Usually you have to resort to burning or remove the paint chemically.

Old oil paint is burned out with a blowtorch. Directing the flame of the lamp so that it touches the surface, slowly move the lamp as the paint film softens and swells. Immediately, following the flame of the lamp, until the film has cooled and strengthened, the paint is cleaned with a steel spatula. The work is done by one painter. Blowtorch the painter holds in his left hand, and right hand cleans the surface with a spatula.
To destroy the film of old oil paint, as a rule, the following composition containing strong alkali is used.

Composition with chalk or lime to remove old paint

Ground chalk or lime dough - 0.5 kg
Asbestos dust - 0.5 kg
20% caustic soda solution - Until a paste is obtained

Such a composition is applied as a putty with a wooden or steel spatula and left on the surface until the paint layer softens, after which the composition is cleaned from the surface along with the softened paint with a steel spatula.

The cleaned mass can be reused several times after adding a solution of caustic soda to it until the required viscosity is obtained. To neutralize the alkali remaining on the surface cleaned of paint, the latter is washed with a 1-2% solution of any acid and rinsed clean water. After burning or cleaning, the surface is prepared for painting. in the usual way. Previously painted roofs must be cleaned of all loose paint and all rust removed.

Ivanov V.P. Painting, wallpaper and glass works, M., 1958.

Surfaces to be painted with non-aqueous compounds must be dry, dust-free after sanding and primed.

small flat areas walls are painted with a handbrake brush, fur rollers, and large surfaces - with paint sprayers.

Window frames, metal lattice structures are painted with handbrake brushes, flute brushes.

The painting of the walls begins with beating the top of the painting with a cord dyed with dry pigment. The resulting line is taken away with a handbrake brush.

To paint the wall, the brush is first dipped into the paint for half the length of the pile and the excess is squeezed out on the edge of the container. Coloring begins with vertical sections (Fig. 1), then the paint is distributed in zigzag movements and shaded with vertical movements.

Oil paints are applied in two layers, keeping the first layer for 1-2 days.

Figure 1. Sequence of application of non-aqueous formulations by brush

When painting on the surface, bumps and brush marks often remain.

To obtain a smooth and glossy surface, the freshly painted areas are flattened. And to get rough, matte texture- facing.

Flattening (Fig. 2) is performed with a dry flattened brush without pressure, only with the very tip of the pile, with vertical movements.

Figure 2. Flattening with a dry brush

To trim the surface (Fig. 3), they take a dry trimming brush and strike the paint layer (once). Facing allows you to create a smooth, evenly diffusing light, rough surface.

Figure 3. Surface trimming

The walls are painted with a roller vertical stripes. To do this, first it is lowered into a bath of paint and the excess is squeezed out, rolling it over the grid.

The roller is applied to the wall and moves it up and down along the surface.

Each subsequent painting strip should overlap the previous one by 2 ... 3 cm. Paint the surface with a roller until it gives up all the paint, shade it with a dry roller in reverse motion.

When painting doors, brushes and rollers are used. smooth surface doors start painting from the upper left corner, then cover areas nearby. Further, going down, paint the entire door. If the door is with contour trim, then it is more expedient to paint it first, and then the door leaf or panels.

The painting of windows begins with the movable sash, then the gratings of the fixed sash are painted, and finally the frame and window sill.

To prevent traces of paint from remaining on the glass, shields made of tin, cardboard, plywood are used. The edge of the shield is cut into a chamfer so that there are no non-paints left. You can also apply paint adhesive tape, gluing it to the glass along the perimeter of the surface to be painted.

After work, it can be easily removed from the glass, leaving no traces of paint.

When painting wood door panels and window casings, the final shading is performed along the fibers of the wood.

Painting of pipes, radiators and other gratings metal structures produced with shaped brushes, handbrake brushes, a double roller, zigeyka mittens, a spray gun.

Defects in colorings made with lime and adhesive compositions. Defects in this case are mainly due to non-compliance with the technology of work. Most often, they can only be fixed with a complete rework. Consider the reasons for the formation of defects.

The grinding of the paint layer occurs because little glue was added to the prepared paint composition or chalk with large particles was used; not nroce^,. the prepared paint composition was poured.

Peeling of the paint film can be caused by the following - a) the paint composition was too thick or repeatedly applied to the same place; b) an excessive amount of glue has been introduced; c) painting is done with a thick layer of previously applied paint or with a weak putty.

Correct by carefully blending the applied composition with water using a brush. In this case, part of the coating is washed off. If this does not help, then it is necessary to remove the entire layer of paint, grind the surface, prime and paint.

The translucence of the previous paint layer is possible because a primer of a different color was used than the paint composition, or it was not very opaque.

To correct the surface, re-paint. If this does not help, then you will have to re-primer, using a pear tinted under the paint layer.

Rust stains are possible from prolonged water flow through the plaster or from seepage of resinous substances through the plaster.

Correct by eliminating the causes that caused the formation rusty spots, removing rusty plaster and replacing it with a new one. Another way is possible: peel off the old paint, rinse the surface with a warm 3% solution of hydrochloric acid dry, paint oil paint(oil or alcohol varnish), primed and painted.

Grease stains on plaster come from non-drying belly or mineral oils. Correction is possible only by cutting out oiled spots of plaster, applying a new, thorough drying, painting with oil paint the joints near the new plaster, priming and painting.

Efflorescence occurs from the release of soluble salts by the surface, which form a white crystalline coating on the painting or plaster. Remove efflorescence by thorough drying and cleaning the surface with steel brushes, grinding the plaster, drying, painting the corrected area with oil paint, putty, priming and painting with adhesive paint.

"Nataski" can be when painting the surface without priming or if the painting was carried out according to old paint, primed with a weak primer without shading.

To eliminate the defect, it is necessary to thoroughly wash out the old nabel with water, and even better, clean it off, grind it, prime it and repaint it.

Banding is possible from the addition of dry pigments to the paint composition, from poor mixing of the composition, uneven shading and pressure on the brush. Streaking can be eliminated by thoroughly rinsing with water and painting with a liquid paint composition using an airbrush.

"Veins" occur when surfaces are not well primed (especially with embroidered cracks smeared with gypsum Mortar) or because the embroidered cracks are not sufficiently repaired. To correct, wash out or completely remove the paint layer, prime the surfaces well (prime cracks twice) and paint. Insufficiently worn seams should be corrected by rubbing, primed and painted.

Creases are formed from the use of too thick (or too thin) paint composition. The paint composition must be diluted to normal viscosity and repainted.

The rough texture of the color and the accumulation of small tubercles are possible because the grout was made with coarse sand or the primer and the paint composition were used unfiltered. Correct by washing or grinding the surface, priming and painting with a strained composition.

Splashes, streaks and gaps. Splashes may be due to an enlarged orifice in the nozzle against the norm, streaks - due to a liquid paint composition or uneven application, gaps - due to incorrect work with a brush, roller, etc. Correct by washing the surface with water, priming and painting .

Marbled spots arise from the use of a heavily sealed paint composition. Correction is possible by washing out the paint layer and painting (or priming and painting) with a normally sealed composition.

Joints are visible due to inept work with brushes, rollers, spray guns or when painting on weak primer. You can fix the surface by washing the surface with water and performing a primer and painting.

A change in the color of the paint can occur as a result of the use of pigments that are not resistant to alkalis, light, sulfur dioxide, hydrogen sulfide. Correct by washing off the applied paint, priming and staining with stable pigments.

A panel with uneven coloring may be due to incorrect pressure on the panel brush or excessive thick paint. The elongated panel should be redone.

The painted surface dries unevenly because a non-uniform strength was used. primer composition and there were drafts. For correction, drafts should be eliminated and the correct preparation of the primer should be checked.

Defects in paints made with oil and enamel compositions.

Brush marks can be seen when using thick paint and not enough shading. Dried paint is cleaned with pumice or sandpaper and re-painted with the prepared paint composition.

The joints are noticeable because the painting was carried out with quick-drying paints with breaks in the same place, i.e., several grips. To correct the work, several people redo the work, working simultaneously without interruption. Dock should be near the pilasters, in the corners, etc.
Leaks appear from application liquid paint applied in abundance on surfaces without sufficient shading. The dried paint is cleaned with sandpaper or pumice stone and dyed with a composition of normal density.

The rough texture of the coloring can be from the use of non-strained paint, painting over poorly executed putty or from its poor stripping (grinding). Correction consists in carefully sanding or pumice the painted surface and repainting.

"Crocodile skin" can be from applying quick-drying paint over insufficiently dry preparation. Correct by cleaning with sandpaper or pumice, pro-oiling, puttying and staining.

Wrinkles in the coloring are from applying paint with a thick layer. Correction by stripping, puttying and painting.

Rusty and dark spots are possible because resinous and mineral oil stains were not removed during preparation. Correct by removing defective places or thorough cleaning, washing with acids, alkalis, coating with two or three layers of alcohol varnish or nitro varnish and re-painting.

Spots of different colors with non-drying paint can occur when painting on wet paint. Correction - neutralization of alkalis in it with a weak solution of hydrochloric acid, rinsing with clean water, good drying, priming, puttying, painting with high-quality materials.

Peeling of the top layer of paint occurs when staining contaminated or previously painted wax formulations surfaces. Correction: remove loose paint, clean surfaces well with pumice stone or wash with soapy and clean water, dry and paint.

Swelling of paint is observed when painting poorly dried wooden surfaces.

Often, when using adhesive compositions, damp spots or separate places with a “frozen” color appear on the painted surface, the color of which is much darker. This happens when not quite dry plaster is painted. Such defects are eliminated by washing the entire surface with warm water, drying damp places, and then priming and painting again.

When using colors with an insufficient amount of glue, the paint layer is sanded, which is removed by also washing the surface, then priming and painting with a color with a normal content of glue.

When using colors with excess glue, as well as when painting surfaces puttied or primed with compositions containing an excess amount of glue, the color fades: marble-like spots and stripes appear. To eliminate them, the paint is washed off hot water, the surface is washed several times with warm water and, when it dries, covered with a very weak primer (with a small amount of glue) - the putty glue should fix the weak primer. The primer for these purposes is prepared according to the following recipe:

Primer on re-glued putty (for 10 liters of composition)

• Copper vitriol .............................................................. ...........0.05 kg
• Laundry soap ................................................................ ....0.05 kg
• Animal glue (10%) .............................................. .0.55 l

In addition to the previously listed defects resulting from painting with aqueous compositions, including adhesives, there may be other defects. The reasons for their appearance and ways to eliminate them are indicated in Table. fifteen.

Quality water stains determined mainly by appearance completed work.

Table 15
Defects water colors

test questions

1. List the technological operations in preparation for painting:
   • 1.1. improved adhesive;
   • 1.2. lime plaster and concrete;
   • 1.3. improved casein;
   • 1.4. emulsion.
2. What are the requirements of SNiP for the quality of painting with aqueous compositions?