Defects in car painting and how to eliminate them
Content
Trouble after body work can be avoided if you consider the factors that lead to marriage. In addition, many problems do not appear immediately, but after some time.
Defects in painting a car are common for beginners and experienced painters. Even with the use of quality materials, the correct application of the liquid mixture, there is no guarantee that the coating of the machine will be smooth and without flaws.
Car painting defects: types and causes
Trouble after body work can be avoided if you consider the factors that lead to marriage. In addition, many problems do not appear immediately, but after some time.
Material drawdown
These visible traces of scratches under a layer of varnish. They appear on the base paint during the final polymerization of liquid formulations.
Related factors:
- Violation of risk treatment rules.
- Exceeding the thickness of the primer or putty.
- Poor drying of layers.
- Incorrect proportion of thinners or hardeners.
- Use of low quality products.
Drawdown is usually observed a few weeks after the repair.
Boiling varnish
The problem looks like small white dots on the surface of the body. This is due to the fact that during evaporation the solvent froze in the form of bubbles.
This problem is typical in the following cases:
- applying a large amount of varnish;
- using several of its types in one place;
- accelerated drying with a special chamber or lamps.
Craters
These car paint defects are funnel-shaped depressions that can reach sizes up to 3 mm. Sometimes a primer is visible at their bottom. Marriage is also called "fisheye".
Related factors:
- insufficiently thorough degreasing of the body;
- use of unsuitable cleaning products (e.g. shampoo);
- ingress of oil and water particles from the compressor for spraying coatings;
- incorrect air gun settings;
- remnants of silicone on the old coating.
As a result, particles of wax, grease or polish stick to the car enamel. Craters are formed during the spraying of the paintwork or after the final treatment.
Hologram effect
This marriage is clearly visible in bright sunlight. It occurs due to the use of a rotary machine at high speeds and unsuitable materials (worn polishing wheels, coarse abrasive paste). A side effect of the hologram also leads to manual surface treatment with dirty microfiber.
Spot punctures
These defects in the car's paintwork after painting look like small holes on the surface. Unlike craters, holes have smooth and sharp edges.
Local body painting
Punctures appear due to the use of poor polyester sealants or by ignoring the sanding of a porous surface.
The appearance of bubbles
This may occur during staining or at the end of this process. If the blisters are single, then they are caused by micro-risks on the metal. When there are a lot of bubbles, the main reason for their appearance is water, grease, moisture on the surface or working with putty using the “wet” method.
The wrinkling effect
Paint can lift and shrink on any surface of the car. The “chewed” areas have a sandy structure and pronounced halos where the polymerization of materials has occurred. The problem is caused by the incompatibility of the components of the old and new solvent, insufficient drying of the "substrate", the application of thick layers of paintwork.
water stains
This trouble manifests itself in the form of round marks on the surface of the body. This happens due to liquid getting on the varnish before drying, or a hardener was added to the enamel.
Color change
This phenomenon can occur immediately or some time after the repair. Causes:
- priming with low-quality products;
- non-compliance with the proportion when adding a hardener;
- incorrect coloring;
- lack of proper sealing of putty and reactive primers;
- uncleaned surface from bitumen, resins, bird excrement and other reagents.
As a result, the base shade of the coating is very different from the applied paintwork.
Large shagreen (orange peel)
Such a coating has poor paint spillage, many small depressions and a rough structure. The problem occurs when using:
- thick consistency;
- volatile solvent;
- excess or insufficient amount of varnish;
- LCP with low temperature.
- spray gun too far from the object;
- sprayer with a large nozzle and low working pressure.
This marriage is quite difficult to completely eliminate. It happens even in cars with factory painting.
Streaks of varnish or base
The phenomenon is characterized by thickenings on the body with the paintwork running down the inclined and vertical panels of the vehicle. Causes:
- Enamel or base on dirty finish.
- Viscous paint.
- Excess slowly evaporating solvent.
- Close spray distance.
- Uneven application of the mixture.
Sagging occurs when the surface or applied material is very cold (below 15 degrees).
Cracking of paintwork (erosion)
The problem happens when the dried varnish is deformed. The prerequisites for cracks in the lacquer film are non-compliance with the temperature regime, accelerated drying with the help of improvised means and the use of a larger amount of hardener.
Cloudiness ("apples")
The defect is not pronounced turbidity on the surface. When illuminated, matte stripes and spots are visible on the body instead of gloss. Causes:
- violation of the rules of painting;
- applying varnish to the "wet" mixture;
- excess solvent;
- incorrect equipment parameters;
- drafts in the room or insufficient ventilation.
Haze occurs only when using a grain base. This is a fairly common occurrence on mixtures with a shade of "metallic gray".
Peeling paint or varnish
The problem is due to poor adhesion of the coating. Causes:
- short drying of the surface;
- violation of gradation by abrasives;
- plastic processing without primers;
- non-compliance with the proportion of solutions.
Due to poor adhesion, the paintwork begins to “peel off” and even fall off when the car is moving.
weediness
These defects in the paintwork of the car after painting occur when finishing on the street, in a workshop or in a garage.
Car painting and straightening
Associated factors of garbage settling:
- dusty room;
- lack of ventilation;
- dirty clothes;
- neglecting the filtration of material through a strainer.
It is impossible to completely get rid of weeds even in sealed chambers.
Elimination of defects in car painting with your own hands: expert opinion
The table shows the solutions for each case.
| Marriage | Fixing the problem |
| Drawdown | New priming + applying fresh enamel |
| Boiling varnish | Staining with "slow" thinner |
| Crater | Polishing with anti-silicone grease + applying a new base |
| Hologram | Varnish the area |
| Spot punctures | Repainting |
| water stains | Application of a new base or complete replacement of paintwork in case of corrosion |
| Color change | |
| Bubbles | |
| wrinkling | Repainting with sealants |
| Shagreen | Coarse sanding + polishing |
| smudges | Sanding with a bar or fine sandpaper |
| Rastreskivanie | Complete replacement of primer and paintwork |
| Lacquer peeling | Removal of damaged layers, polishing with shot blasting or sandpaper, application of new enamel |
| weediness | Dust in varnish - polishing, in the base - painting |
In this list, the main troubles that most painters have encountered.
The most common defects in the paintwork of the car body
When finishing work, certain problems are most often encountered.
smudges. They arise due to uneven application of paintwork, improper consistency of solutions, excess paint on the surface and incorrect settings of the paint apparatus.
Grain. It appears after dust has settled on the treated area. To prevent the problem, finish in a draft-free room. Apply the mixture with a high pressure spray gun (200-500 bar). Use fine filters.
Long curing paintwork. This happens when excess solvent is added or due to the cooled surface. The problem is eliminated through drying at a temperature acceptable for the enamel.
Matte spots appeared after painting the car
They can form on any surface, but most often occur in areas with putty. In these places, the enamel is absorbed much more strongly than in other areas.
The reasons:
- A thin layer of paint.
- High atmospheric humidity.
- Drafts.
- Low temperature in the working area (less than +15°C).
- Wrong mixture.
- excess solvent.
Stains may swell if not removed through polishing, re-smoothing and application of a liquid compound.
Technology for eliminating defects in car painting
According to the recommendations of experts, it is better to fix problems after a month, so as not to do the work again. This is due to the fact that the paintwork by this time will complete the complete polymerization with the surface. Some defects in car painting according to GOST (for example, drawdown) will appear after the varnish has completely dried.
Then start fixing the problems. The procedure consists of grinding, abrasive and protective polishing.
Grinding is carried out by "wet" and "dry" method. In the first case, the processing is done with water, sandpaper, a grater and improvised means. The dry method is carried out using an orbital machine. The gradation rule must be observed (first, materials with large grains are used, then with smaller ones).
Painting technology
Abrasive polishing is carried out using 2-3 pastes and foam rubber circles. First remove all sanding dust. After that, a layer of paste 40x40 cm in size is applied to the area and circular movements are made.
If you know what defects there are when painting a car and how to eliminate them, then the driver will save his money, time and nerves. You do not have to contact the repair shop, as the problem can be fixed with your own hands.
