After varnishing, the wood turned white. Possible problems when applying varnish and ways to eliminate them

1. The varnish does not dry out

· Substances (natural oils, resins, etc.) contained in the thickness of wood make drying difficult. For example, in some cases when working with varnishes based on artificial resins on exotic wood species;

· Old, wax-impregnated floor - wax residues cause delay in drying of PU-, acid-curing and artificial resin-based varnishes;

· Too little or no hardener (for two-component varnishes);

· Too much low temperature indoor air (below +10°);

· High air temperature in the room, but low temperature of the parquet, correspondingly insufficient oxygen flow (difficult access fresh air);

· The “wrong” hardener was used, for example, a hardener for PU varnish was added to an acid-curing varnish.

If the delay in drying the varnish is caused by substances contained in the wood or too low a temperature, then to eliminate this problem it is usually enough to raise the temperature to +20ºС and ensure good air access ( not a draft!!!). After some time, the drying process will be activated again and the varnish will dry normally. If you use the wrong hardener, the varnish will most likely have to be washed off. In some cases, for acid-curing varnishes, it is sufficient to apply to the adhesive surface. thin layer pure hardener. However, after the varnish has hardened, the entire surface will need to be completely sanded.

2. The appearance of cloudy, white spots and tracks

· The temperature of the varnish used was too low;

· The floor temperature was low. Air humidity is very high;

· The overall indoor humidity (especially in new buildings) is too high.

White spots always indicate that condensation has fallen onto a fresh varnish film. excess humidity. It is usually sufficient to treat the whitened areas with a solvent, Pay attention to the content of hazardous substances! In any case, after this operation it is necessary to apply another layer of varnish, having first raised the temperature in the room to the required value.

3. “Blistering” (swelling) of the varnish

· The scheme for constructing the varnish layer was incorrectly chosen - for example, solvent-based PU varnish is used with a nitrocellulose primer;

· “wrong” solvent;

· The working tool is still impregnated with a cleaner, which is mixed with the varnish used.

“Bloating” in a limited area can be eliminated by sanding and then applying another layer of varnish, but if the entire surface has “raised,” it is necessary to completely sand off the entire varnish and apply it again.

4. Bubble Formation

· Cold varnish;

· Too thick layer of varnish;

· Exposure to direct sunlight;

· Unsuitable rollers or brushes.

Bubbles in varnish occur when a film has already formed on the surface of the varnish layer, but its lower part remains liquid. The evaporating, rising solvent vapors tend to “pierce” the film, thus “blowing out” bubbles. The only solution is complete sanding and reapplying varnish.

5. “Scaling”, layering of varnish

· Temperature in the room or on the floor surface is too high;

· Too thick layer of varnish;

· Slow pace of work;

· Unscrupulous approach to the work schedule or the “wrong” working tool.

By adding a solvent, you can change the viscosity of almost any varnish, thus increasing its fluidity. But usually it is enough to change the rhythm of the work, minimizing the time for “joining” the previously treated area with the new one. During the heating season, the temperature of the batteries should be significantly reduced. Avoid drafts!!!

6. Formation of "craters"

· the working tool is not in order (especially the rollers);

· the solvent was chosen incorrectly;

· draft;

· the varnish is too cold;

· the surface is contaminated with silicone.

“Craters” can be eliminated by carefully (matte) intermediate grinding and no less thorough surface treatment with a metal spatula, the so-called “ZERO-PUTTY”. The varnish applied with a spatula must dry well; it should not be sanded. After this, another layer of varnish is applied. Many parquet varnishes are susceptible to this “disease” in places of drafts, as well as if the varnish has been stored for a long time at a very low temperature and spreads poorly (“thickly”).

7. "Roughness"

· Evenly distributed bubbles;

· Small particles of varnish film from the working container;

· Incorrect grinding.

“Roughness” often causes the greatest difficulties, since incomplete data on the reasons for its appearance are often provided. In reality, the basis of most complaints is dirt, although often the cause of roughness can only be determined with the help of a magnifying glass. Lumps of varnish from the work container are the second most common cause. Therefore, it is especially important that before starting work, all tools, containers and work clothes were perfectly clean. Varnish containing solid particles must be passed through a sieve.

8. "Wrinkles"

· Applying the next coat of varnish too early;

· Too thick application of the subsequent layer of varnish;

· “wrong” solvent.

This phenomenon is observed especially with varnishes based on artificial resins - when each subsequent layer of varnish is applied too thickly or quickly. If the entire surface is covered with “wrinkles,” you cannot do without complete sanding.

9. Matte-glossy areas, formation of “clouds”

Many matte varnishes are designed to be applied in a layer of max. up to 150 g/m. sq.. When applying a thicker layer, matting substances “spread” unevenly, depositing in each fresh layer. As a result, matte-glossy areas appear, especially in the “joining” areas. The situation can be corrected by intermediate sanding and subsequent application of matte varnish in a thin layer.

Car paintingit's complicated technological process, in which the chance of defects occurring is very high. Especially if the painting is not done by a professional painter and without for car painting. In this article we will look at the most basic and commondefects in car painting.

If you are a beginner and do not have enough experience and practice, then the occurrence of defects during painting increases significantly.
Defects appear from various factors, such as: inexperience of the master, unsuitable conditions, correct use material, etc. Below is a list of the main painting defects, their possible causes are indicated and recommendations are given for their elimination.

In the most severe cases, loss of traction upper layer The paint is easily separated from the primer layer - or old paint, or all layers together are separated from the metal.

Generally, weak grip is limited to areas that are sensitive to impact or impact. This defect is usually discovered immediately after painting when the masking tape is removed.

Poor adhesion results from insufficient bonds between the paint film and the surface to which it is applied. This usually occurs due to insufficient cleaning of the surface and poor preparation for painting, or the adhesion may be impaired later by exposure to moisture or other deterioration of the film.

The main causes of poor grip are:

Poor quality, due to which contaminants remain on it (wax, oil, water, rust, dust, etc.). These contaminants prevent strong adhesion of the paint layer to the surface.
Insufficient smoothing of the primer layer with filler before painting.
Insufficient mixing of materials
Using primer coatings that are not suitable for either metal or paint.
Incorrect application of paint (“dry” spraying).
Using a surface unsuitable for painting.
Using the wrong solvent
Masking a freshly painted surface too quickly in two-tone coatings.
Careless masking can lead to damage to the paint layer when removing the masking tape from the surface.
Excessive exposure to high temperature during the thermal drying progress of the vehicle or excessively high drying temperature.

Remove the paint layer over an area much larger than the damaged area using grinder or sandblaster (to metal if necessary).

If loss of adhesion is caused by masking deficiencies, treat the damaged surface and then repaint it.

Bubbling consists of the formation of bubbles of varying sizes and densities on the surface of the paint layer. Bubbling appears on both new and old layers, and mainly appears at the moment when high humidity gives way to severe frosts.

Bubbling is caused by moisture or air trapped under the paint layer. Water penetrates even the best coatings when the body is exposed to sudden temperature changes. Moisture that gets into the paint layer expands and thus creates pressure. This weakens the adhesion between the layers and thus leads to the formation of bubbles.

The most common cause of blistering is that the surface is not properly cleaned and prepared for painting, leaving dirt between the filler and the metal or between the primer and the paint. Typical contaminants include oil from air ducts, finger grease, dust, dirt and salt. So make sure the surface is clean and clean it before painting.
Use of improper solvent.
Excessive thickness of the paint layer and insufficient waiting time between coats. This can cause solvent to build up in the paint. Later, when the solvent evaporates, bubbles form. Therefore, do not unnaturally speed up the drying of each layer of paint.
Inadequate thickness of the primer paint coating.
Exposure to dampness or humidity before painting, as well as continued subsequent exposure to these factors.

If there is severe bubbling, remove the paint down to the metal, then completely repaint the surface.

For less blistering, clean up the bubbling area and either apply only a thin coat of paint or refinish the surface.

The paint film does not shine well and does not cover the primer and metal well. Typically this film has a smooth surface, does not sag or bubble.

The paint layer is too thin.
Poor preparation of the working surface or use of too coarse grain when smoothing sandpaper.
Defect during priming.
Poor adhesion of the primer to the surface.

If the paint layer is too thin, reduce the solvent content of the paint.

In most other cases it is necessary to re-smooth the surface, then carefully prepare the surface (using appropriate preparations where necessary) and apply a coat of paint of the appropriate viscosity.

Small bubbles in the paint layer that, upon closer inspection, have tiny holes at the tops. This phenomenon is mainly observed at the boundaries of regions with thick coating.

Solvent bubbles form in a thick layer of paint, which, in turn, is formed for the following reasons:

Too much paint supply ().
Paint viscosity is too high.
Moving the spray gun too slowly (more paint than necessary is applied to a small surface).
Too much large overlap layers of paint when sprayed.

Before smoothing and applying the finishing coat of paint, leave the painted surface to dry completely (the drying time of oil paint depends greatly on the thickness of its layer).

Cloudiness appears as a milky white “fog” on the painted surface. If cloudiness is present on the paint coating, it may also be present on the primer. Note that clouding in the primer coat may not be noticeable (as it is usually matte), but it may later develop into blistering or loss of adhesion.

Clouding can occur if painting is done at low temperatures and high humidity, and is caused by moisture entering the paint layer. During the spray painting process, the solvent quickly evaporates, causing the area to be painted to cool. Moisture from the surrounding air condenses on the fresh paint layer, resulting in a milky white “fog”. Possible reasons for this:

Using low-quality (cheap) solvent.
Using a fast-evaporating solvent at low temperatures and high humidity. In such conditions it is necessary to use a special type of solvent. In addition, use a minimal amount of solvent, otherwise the drying process of the applied coating will be significantly slowed down.
Incorrectly set operating parameters of the spray gun, incorrect painting technique or overpressure air.
Incorrect air circulation or insufficient air temperature in the workshop.
The solvent evaporates too quickly when directing a stream of air onto the paint layer.
Draft in the workshop.

In case of slight clouding, wait until the paint has completely dried and remove the defect by polishing.

Repaint defective areas using special solvent.

Spray the above-mentioned special solvent onto the defective areas. At proper conditions this will eliminate the cloudiness.

If none of the above methods work, increase the air temperature in the workshop by at least 5° and ensure there are no drafts.

Microcrack defects are a large number of very small, unrelated cracks that require a magnifying glass to examine. In paintwork, microcracks appear as dull areas and lack of gloss. Cracking consists of many random cracks, often shaped like three-pointed stars. It resembles cracked mud in dry ponds or river banks. These cracks are usually quite deep and penetrate through the top coat of paintwork and sometimes even through the primer/filler. Cracking is usually the result of weakening of the paint film, such as hairline cracks or blistering.

Cracking occurs as a result of weakening of the paint layer, which occurs under the influence of conditions environment. Modern quality paints, when applied properly, rarely crack. The latter appears for the following reasons:

The paint layer is too thick. Applying too thick coats of paint or primer increases the stresses and strains normally present in any paint finish, causing cracks to form even under normal conditions.
Insufficient drying time. The risk of cracking increases when thick layers of paint are applied on top of each other without proper drying time.
Insufficient mixing of paint before use. Poorly mixed paint affects the strength of the paint layer, its flexibility and adhesion, which, in turn, leads to cracks.
Insufficient cleaning and preparation of the surface for painting.

Sand the defective areas to a smooth surface, although in most cases it will be necessary to completely remove the paint down to the metal and repaint the surface.

Paint craters are small, funnel-shaped holes in the paint layer that form during the spray painting process or immediately after spray painting a car. Causes

The appearance of craters is caused by silicone particles. Many modern waxes, paraffins and polishing compounds contain silicone. It firmly adheres to the surface of the paintwork and requires additional measures to remove using alcohol mixtures. Craters appear for the following reasons:

Insufficient surface cleaning and poor preparation for painting. Contaminated surfaces are washed with soap and detergents. It is necessary to take measures to remove traces of silicone from the surface using grease and wax removers.
Contamination can also occur when preparing the surface for painting: from sand dust, lint from used rags, or automotive polishing paste. Even those used on a short time, these substances can cause surface contamination, which in turn will lead to the appearance of craters.
Oil in the air duct of the spray gun. The use of silicone containing anti-crater additives is not recommended. These additives can contaminate the workshop, which may result in loss of adhesion during other work.

Smooth out defective surfaces and apply a new coat of paint.

Rough, unevenly painted surface.

Evaporates too quickly or inappropriate solvent, low
humidity and high ambient temperature
air.
Paint flow is too high.
Air pressure too high.
Too thin layer of paint film.
Spray distance too long.
Poorly prepared primer.

If possible, polish the surface of the part. If the defect is too strong, repaint the part with paint or varnish.

This defect consists of small cracks or crevices in the sharp curves of the panels where touch-up paint has been applied. They appear during or immediately after applying the paint layer to the primer.

Too thick a layer of paint film without adequate drying. This leads to the accumulation of solvent in the layer, which in turn causes cracking.
Poor mixing and use of poorly mixed paints with solvent primers. This leads to a reduced pigment content in the paint, which causes the creation of a spongy surface structure. When a top coat of paint is applied, this structure can collapse, causing shrinkage cavities and crevices that lead to sagging.
Primer solvent is too fast acting and prevents uniform application of the paint layer.
Insufficiently cleaned surface and inadequate preparation for painting. If the protrusions (saggings) in places of minor surface repairs are not sufficiently cleaned, then the applied primer layers may “slide” down from these protrusions due to poor adhesion.
Blow off the primer layer with a paint gun immediately after applying it. This dries the surface of the coating before the air has escaped and the solvent has evaporated, causing shrinkage and cracks in the dried layer.

Remove the top layer of paint from the surface and repaint it.

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More matte surface compared to normal glossy. Note that two-component paints and paints applied with help give greater gloss.

The thickness of the paint coating is too thin.
Scratches from smoothing.
Uneven color (spotting) (see corresponding chapter above).
Insufficient amount of paint.

Re-smooth the surface and apply the next coat of paint.

Uneven surface of the paint layer, similar to orange peel called shagreen. The reason for the appearance of large shagreen is caused by a lack of paint atomization, manifested in poor merging of droplets on the surface, i.e. the drops remain in their places (in the order in which they flew out of the spray gun) and do not spread over the surface. Ideally, the drops should spread and mix with each other, thus forming smooth surface. The reasons for the formation of shagreen are as follows:

Incorrect or incorrect adjustment of the spray gun, too high or too low air pressure, too large a distance between the gun and the surface to be painted, too little paint flow or too wide an air stream.
The workshop temperature is too high (use slow-evaporating solvents).
Materials are not mixed enough. Many finishing paints contain components that promote the coalescence of droplets, so if the paint is not stirred, an “orange peel” defect may occur.
Excessively thin paint coating.
Inadequate paint viscosity.
Drying time between applications was not maintained separate layers, air flow from a paint gun was used to reduce drying time.

So how to remove shagreen after painting a car. After the paint has completely dried, clean the defective area using an abrasive compound or sandpaper (select the grit depending on the condition of the surface). Restore gloss by polishing.

In severe cases, smooth out defective areas with fine-grained sandpaper and repaint the surface.

One of the paint layers peels off or easily separates when removing the adhesive tape at the end of masking from the other, previous layer. This can happen both during the initial painting and during repainting.

Contamination between layers: oil, dust, water, etc.
Excessive exposure to heat or excessive heat when applying primer or topcoat paint.
Too thin a layer of primer or finishing coat.
The interlayer smoothing was poorly carried out, resulting in poor adhesion of the paint layers.
Incompatibility of primer, paint and finishing layers

Smooth the surface down to the base coat and clean the surface thoroughly. In rare cases where there has been previous repainting, it may be necessary to start with bare metal.

One of probably the most common defects is leakage. Drops, smudges and paint runs on vertical or inclined surfaces body

The solvent in the paint evaporates too slowly.
Too thick layer of paint.
Subsequent layers were applied without sufficient drying of the previous ones.
The distance between the spray gun and the surface being treated is too small.
High pressure air.
Spray intensity too high.

How to remove stains and paint and varnish buildup on parts? If the leak is not large, it can be removed using fine sandpaper and a block, and then the surface can be polished. If the sagging and smudges are significant, then the part will have to be repainted. remember, that oil paints they dry quite slowly, and the depth of the sagging of such paint can be significant; in many cases an additional coat of paint is not required.

“Dry” or “semi-dry” drops of paint from a paint gun form a coating of particles that have not adhered to the surface.

Fast drying paint was used.
Incorrect solvent used (too fast evaporating) in warm, dry conditions.
Incorrect spray technique used, i.e. overspraying onto adjacent (painted or unpainted areas).
Excessive kickback caused by incorrect air pressure, viscosity or gun settings.

Lacquer overspray is usually dry and does not adhere strongly to the surface, so it can be eliminated by sanding the partially dried film.

Overspray synthetic enamel is usually wet and adheres firmly to the painted surface. Many of these materials are difficult to polish, so overspray must be removed by wet smoothing and a new coat applied.

Finish Pores are tiny holes (often clustered) in the painted surface.

Microholes can occur for various reasons and are caused by the entry of solvent, moisture or air into the paint layer and their subsequent release (during drying). This is often due to poor paint preparation or incorrect painting technique, and can occur in primer and paint finishes. Microholes can be caused by the following reasons:

The parameters of the spray gun are incorrectly set or it is not being used correctly. The gun was too close to the surface being treated. Insufficient spraying of the primer or paint coat. Pinholes form when air or excess solvent escapes from a painted surface as it dries.
The impact of a stream of air on a freshly painted surface. This leads to air getting inside the paint layer and drying it out too quickly.
The application of a paint layer over a primer or paint coat made by dry spraying.
The jet is contaminated with oil from the compressor or moisture.
The use of heavy coatings with insufficient drying time for each layer.
The putty knife was not used correctly when applying putty or filler. Using the knife at an acute angle causes the material to roll under the blade and air bubbles inside this material.
Error in determining the area to apply filler or putty.

Where pinholes are minor imperfections, they can be removed with filler or smoothed out with fine-grit sandpaper and then reapplied with filler.

In other cases, wet smooth the defective areas of the coating to a depth that guarantees complete elimination of microholes, then repaint the defective surface. You can also remove the defective paint to bare metal and repaint.

Micro-holes that have been exposed to filler or putty after smoothing should be subsequently filled with a thick layer of putty using a putty knife held at a 90° angle to the surface. In this case, the putty is pushed well into the micro-holes.

Note: If you are concerned about pinholes, check all factors that cause paint to dry quickly: paint viscosity, solvent type, ambient temperature, etc.

Almost always dust and debris during painting manifests itself in the form of an uneven accumulation of particles of different sizes on the paint layer.

Debris and dust particles can get onto the painted surface during or after painting. In any case, the reason lies either in lack of cleanliness or in the use of paint that does not correspond to the working conditions of painting. Contamination of the painted surface is caused by:

Contaminated paint or solvent. The debris, of course, could not have been in hermetically sealed cans of paint and solvent before they were opened, but could have entered when a dusty can was opened or when incompletely used materials were not properly stored.
Dust has not been removed after the primer coating has been processed.
Airborne pollution. It can come either from the immediate environment or from more distant sources. Slow drying paints (such as enamels) require clean closed premises for use for two reasons: increased drying time leads to a high probability of dust settling on the freshly painted surface; unlike cellulose paints, the gloss on enamel coatings cannot be restored even by polishing.
Tools and filters are poorly cleaned. It happens that when changing paint, a more active solvent is used, which softens and carries away the dried dirt accumulated in the paint gun.

VARNISH HARDENS SLOWLY

Causes: substances contained in wood (natural oils) prevent the varnish from hardening. For example, varnish based on artificial oil resins (urethane-alkyd, alkyd) does not dry on wood of some exotic species (olive, teak, damask); the surface is poorly polished, the remains of wax mastics are preserved in the old floor coverings and prevent hardening of the varnish layer. This can happen, for example, when using polyurethane anhydrous, acid, urethane-alkyd and alkyd varnishes; the hardener in the two-component varnish is added in insufficient quantities, not mixed or mixed poorly, or not added at all; room temperature is too low (below 10 C); the room temperature is quite high, but the floor surface is cold; insufficient access to fresh air (lack of ventilation); incorrect selection of hardener, for example, instead of an acid hardener, a hardener was added to the varnish for polyurethane varnish.

Remedy: if the slowdown in the hardening process of the varnish is due to substances contained in the wood or the room temperature is too low, then in most cases it is enough to increase the temperature to 20 C and increase ventilation. After some time, the hardening process will be activated again and the varnish will dry; if the wrong hardener was used or it was added in insufficient quantity, then in most cases it is necessary to sand off the applied coating; In some cases, when using acid varnishes, the situation can be corrected if a pure acid hardener is applied to the surface of the uncured varnish with a brush. But after such an operation it is necessary to polish the varnish layer again.

WHITE LOOMS

Causes: the varnish was applied too cold; floor surface temperature is too low, air humidity is too high; the overall humidity in the room is too high (occurs in new buildings).

Remedy: Whitish deposits always indicate that moisture from the air has condensed on a freshly applied layer of varnish. In most cases, treating whitish deposits with a solvent helps. After this, you should always re-varnish. Before applying the next layer, it is necessary to warm up the room and it is especially important to increase the temperature of the floor surface. Swelling of the varnish layer.

DETACHMENT

Causes: incompatibility of varnish layers due to different chemical composition. For example, a top layer of two-component polyurethane varnish is applied to a layer of water-dispersion varnish; incorrect choice of diluent; the tool for applying varnish is saturated with a cleaning agent and during application the varnish is mixed with this preparation or the instrument is poorly cleaned; insufficient intermediate grinding.

Remedy: when swelling on small areas sanding and applying a new layer is possible; When swelling occurs over the entire surface, the situation can only be corrected by completely sanding off the applied varnish coating.

FORMATION OF BUBBLES

Causes: the varnish is too cold; the varnish layer is too thick; flare sun rays; incorrect selection of roller or brush for applying varnish.

Remedy: Bubbles form when the varnish layer hardens only on the surface, but remains liquid inside. The evaporating and rising solvent cannot penetrate the hardened film and accumulates in the form of bubbles. The situation can be corrected only by polishing the surface of the film and reapplying a layer of varnish.

COATING STRIPES

Causes: too high room temperature or high floor temperature; the layer of varnish applied is too thick; the pace of work is too slow, the varnished areas have time to dry before the adjacent area is coated, and there is no adhesion between adjacent films; carelessness in work or incorrect selection of tools for applying varnish.

Remedy: the viscosity of all varnishes, and therefore their technological properties, including adhesion, can be somewhat improved by adding thinners; When applying the first layer, the absorbent component is always greater than when covering the remaining layers of varnish. When applying the second and subsequent layers, it is advisable to add a small amount of solvent to the varnish to improve adhesion to the previous film; in most cases, it is enough to change the rhythm of work so that adjacent areas are coated with varnish as quickly as possible and do not have time to dry; To reduce the drying rate of the film, reducing heating and reducing the intensity of ventilation helps.

CRATER FORMATION

Causes: the varnish application tool is not in order; This especially applies to rollers; incorrect choice of diluent; draft; the applied varnish is too cold; “silicon poisoning” of the varnish surface.

Remedy: In a drafty environment, many parquet varnishes are prone to crater formation, especially if the applied varnish was overcooled during storage and became excessively viscous. The situation can be corrected by performing a complete intermediate polishing of the front layer. After this, the polished film is polished with a metal spatula with sharp edges. After puttying, the surface dries well, but should no longer be sanded; then a new layer of varnish is applied.

ROUGHNESS ">

In most cases, it is very difficult to give an exact definition of the concept of “roughness”, since the roughness parameters are often not well known.

Causes: very small bubbles are distributed throughout the film; dust got on the film; improper intermediate sanding (polishing) of the varnish; Remnants of varnish crust from the container for applying varnish got on the film; greasy fingerprints on the instrument.

→ White spots

You can remove white stains on furniture from alcohol, acetone, iron, and water in various ways. Polishing, varnish regeneration, complete replacement varnish coating. Our workshop removes white spots in both full and partial restorations.

White spots are destroyed varnish. They are removed by removing the damage followed by polishing. They arise for various reasons, the consequence of which is the destruction of the film or its detachment from the surface of the tree. Removing white spots is much more difficult than preventing their appearance.

White spots from alcohol

Liquids containing alcohol leave white spots due to the chemical activity of the solution. Alcohol molecules react with the molecules of the varnish finish, destroying it, and the transparency of the varnish is impaired. Minor damage to modern varnish can be eliminated by polishing. To do this, use a thin abrasive paste to remove the damage until the polish remains intact. The varnish will become thinner, but there will be no stain.

Preventive measures: cover the tabletop of expensive furniture with organic glass cut to shape.

Acetone stains

The mechanism for the appearance of acetone stains is the same as in the previous case, but acetone is more active, the destruction occurs deeper and faster. Correction of the defect by completely replacing the varnish finish.

Stains from iron, hot, direct sunlight

White spots are left behind by cups of hot drinks. Very ugly marks in the shape of crescents and circles are a result of exposure to hot cans, glasses, bottles.

When heated, the polymer, which is any modern varnish, changes density, therefore, changes physical properties, namely, transparency. This happens throughout the entire finishing depth. Elimination - complete replacement in a restoration workshop by a professional restorer using special equipment.

White water spots

Appear on antique furniture finished with shellac. Or modern furniture after using expensive care products containing wax, dyes, natural resins (rosin, shellac). When interacting with moisture, the resin turns white and the dye becomes discolored. If the product has turned white, remove it with a dry cloth. If the shellac finish has become unusable, restoration cannot be avoided.

Shapeless light spots appear on modern wooden furniture due to moisture getting under the layer of durable moisture-resistant varnish. Water that gets under the cracks and scratches does not evaporate for a long time and saturates the wood, causing peeling. In places of damage, color distortion is observed.

Currently, there are a large number of modern durable products for coating wooden surfaces. Special varnishes for coating wood in conditions of high humidity and temperature changes. Everything about these varnishes is great, but one thing is bad - they are not suitable for antique furniture. Modern varnishes give wood external properties plastic. Only oil-based polishes and varnishes are suitable for finishing antique furniture.

All alcohol polishes for wood, which were used to cover furniture from the 18th century until the 60s of the 20th century, are destroyed under the influence of moisture and high temperatures. Even moist air, penetrating into cracks, provokes damage in the form of white spots.

Polishing furniture with varnish is long-lasting and labor-intensive process, requiring patience and skill. There was a separate profession - polisher. Since polishing with shellac is gentle, every six months, a polisher was invited to rich houses with expensive furnishings who polished all the furniture, simultaneously cleaning and removing white deposits. Over time, the layer of shellac increased. Shellac polish has a golden hue Brown color, with increasing thickness, the color intensity also increases. So antique furniture becomes more beautiful over time.

The diagnosis is as follows: the varnish has turned white. Lost transparency. As org. glass after exposure to a chemical or abrasive. This could happen for several reasons.

So, let's figure it out various defects arising when painting a car body and which occur most often on the difficult path of a car painter, even a very experienced one. How to “treat” them and prevent them from appearing in the future.

Dust and debris

Most common painting defects The paintwork (paint and varnish coating) on the car body is undoubtedly debris and specks of dust on a freshly painted surface.
The reasons and methods of dealing with these defects are described in detail in the article “How to deal with dust and debris when painting a car,” but what to do if, despite all our heroic efforts, debris still sticks to the fresh paint?
There is only one way, after waiting for the final hardening of the varnish or enamel, sand off the top layer.

The surface is sanded in two ways: dry with an orbital sander or with water manually. The machine uses Velcro abrasive pads with P1000-2000 grit. Gradually moving from coarse grains to finer ones.

When using the wet method, to eliminate the defect, the sandpaper must be taken with a finer grain of 2000 or higher. Then all painting defects are sanded down. The technology is described in detail in the article “How to properly polish a car.” When sanding a painted part, you should be careful and gentle so as not to rub through to the bottom layer.

Drips of paint (varnish)

Drips or “snot” when painting - well, what would you do without them? Almost anyone who tries their hand at painting goes through this misunderstanding. Even experienced painters have such incidents.
There are many reasons for this painting defect.

I’ll simply list the possible causes of this defect, separated by commas: too liquid paint or varnish, the intermediate drying between the application of the subsequent layer is insufficient, the paint was sprayed from a very close distance, the temperature of the painted surface is colder than the paint.

It is quite difficult to fix; more often than not you have to wash everything off and repaint it. But if you have patience and the “snot” is not very loose, then you can try to correct this painting defect.

Cratering (fisheye)

Another unpleasant painting defect, the so-called “fish eye”, is organized in the form of a crater on the very first layer of paint, through which the primer is visible. Small holes are visible on the coating. Sometimes the underlying layer is visible at the bottom of the crater.

The reasons are most often prosaic. Poorly degreased surface (touched with fingers after degreasing, etc.), not treated with anti-silicone, oil splashes from the air duct from the compressor.

This defect usually appears on the first layer of applied pigment (auto enamel, paint), so if you dry it a little longer than usual, then perhaps the fisheye can be filled in with subsequent layers. This method works especially well when painting with metallic paint, when applying the first layer of base (pigment).

In case of fatal “eyes”, from large perches, only complete repainting of the part can save you.

Matte coating

The surface of the paint becomes matte after drying. This type of paint defect does not appear immediately. After painting, you won’t be overjoyed, everything shines, everything seems to be top-notch! Come the next day, and the entire painted surface has become cloudy, as if it had become dull.

Such a painting defect can occur for several reasons. One of the main ones is high air humidity, high blood pressure in the system during application, which leads to cooling of the paint (varnish), and, consequently, to moisture condensation on the surface of the coating.
It is also possible that the thinner was used too quickly, causing the surface to cool and causing moisture to condense on the freshly applied coating.

This disgrace can only be cured by deep polishing, possibly together with grinding.

Bubble breakthrough

On the surface of a freshly painted part, after a short drying period, tiny holes appear from burst bubbles, which look like pin pricks.

This painting defect appears due to the incorrect use of a solvent (thinner), for example, too fast for the ambient temperature.

Very thick layers are applied after a short drying time between layers.
- The element heating (drying) was turned on immediately after painting or the drying temperature was too high.

Only grinding followed by polishing will help to partially eliminate this defect.

Pollination on a freshly painted surface

Another frequently occurring defect is paint dusting on a freshly painted surface.
This kind of incident occurs when a new portion of paint accidentally falls onto an already slightly dried surface. And when it dries, it becomes rough-matte (like sand).

Due to adhering particles of dry paint, the surface has a rough sandy texture to the touch. It is also possible that the paint (varnish) is too viscous due to a lack of thinner, or the speed of the paint gun is too fast.
Perhaps the distance from the gun to the surface to be painted is too large or there is too much pressure at the spray gun outlet.

It can only be treated by grinding and polishing.

Unpainted surface (unevenly painted)

And one of the simplest, but at the same time the most unpleasant defect is an insufficiently painted surface. Or as painters call it - “not painted”.

When, after drying, the soil clearly shows through, or the applied layers of paint (pigment) look like a zebra or clouds. The underlying layer is visible through the finishing coating.
Typically, unpainting occurs on difficult-to-paint surfaces, corners and edges, as well as along the bottom of the car. You can only protect yourself correct technique applying layers, with an overlap of one third, and also good lighting in order to see what you are doing.

This defect can only be corrected by repainting.

Risks under varnish

This defect often manifests itself in inexperienced car painters who do not sufficiently control the size of the abrasive, which they use, for example, to sand off the primer on parts before painting. Sometimes, in an effort to quickly remove soil or old paint, they use abrasive sandpaper with large grains, the risks from which cannot be filled in with paint and varnish in the future. It is also possible that the preparation was simply not done carefully; the painter could simply not have paid attention to the fact that he did not rub down large risks with a finer abrasive. And, of course, in this case, when the paintwork dries, their outlines begin to appear.

This defect can only be treated by sanding and polishing, provided that the marks are not very deep and the varnish has been poured quite well (there is something to grind off).

Midge and how to get rid of it

Another unpleasant defect often occurs when painting in a garage in the summer - these are sneaky midges and other insects that flock to the smell of paint and with all their feet simply plunge into the freshly painted surface, getting stuck in the varnish and sometimes even trying to make a furrow in it, looking for a way out. freedom.

There is only one fight against this evil, you should always have a long one ready sewing needle, with which you can carefully pick up a sneaky insect and pull it out of the varnish that has not yet hardened.

In the future, it can only be treated by grinding and polishing.

In this article, we looked at the most common painting defects among novice painters. These are the main, but of course, not all the problems that a painter faces when painting a car. Basically, all defects, if not too serious, are corrected by grinding and polishing with an abrasive paste, and only neglected options can be cured only by repainting.

And remember, the client pays for the painting, and the painter pays for the repainting!

If during your first attempts at painting a car you find the above defects, do not worry too much and do not despair. Almost all painters go through this, and this article will help you avoid such problems in the future.