Local detachment lacquer Most often starts on horizontal surfaces of the body, such as the roof or hood, where exposure to ultraviolet light and temperature is maximum. If you're in your car varnish stains or went "web" followed by exfoliation, this indicates a violation of adhesion between the base and finishing surface. Ignoring primary symptoms such as clouding or small cracks will inevitably lead to corrosion of the metal under the paint layer, as moisture will gain direct access to unprotected areas.
The main reason why varnish, is the destruction of polymer bonds in the coating structure under the aggressive influence of the external environment. Owners often notice a defect after a winter period, when reagents corrode the protective layer, or a hot summer, provoking thermal expansion of materials. It is important to understand that the process of varnish destruction is irreversible: it is impossible to restore the integrity of the already detached area with a simple wash or polishing, complete removal of the damaged layer is required.
The main causes of the destruction of paint coating
A fundamental error that leads to the slickis a violation of the application technology during primary staining or local repair. If the master saved on the solvent, used a poor-quality hardener or could not withstand a pause between the layers, the chemical reaction of polymerization goes wrong. As a result, a fragile film is formed, which, under the influence of vibration and temperature changes, simply breaks off from the base layer of paint.
The second common group of causes are external mechanical and chemical influences that thin the protective layer. Frequent washings using aggressive autochemistry containing alkalis or acids gradually wash plasticizers out of the varnish structure. Also a critical factor is the abrasive effect of sand and dirt when moving along the highway, creating microcracks, where moisture penetrates.
⚠️ Attention: Using polishing machines with too high rotation speed or rigid circles can “burn” the varnish, making it matte and brittle, which will accelerate its peeling in the future.
It is worth mentioning separately. factory-marriageThis is something that even the big brands are known for. In such cases defective manifests itself massively on large areas of the body in the first 2-3 years of operation. Manufacturers sometimes recognize such cases as warranty, but this requires an independent examination, which will confirm the absence of mechanical damage and violations of operating conditions.
Hidden risk factors
The hidden reason may be to store the car in an unheated garage with high humidity or under dripping condensate from the roof. Bird droppings and wood tar are also negatively affected if not removed within 24 hours – they chemically burn the lacquer layer to the base.
Diagnosis of the condition: stages of damage
Before planning a budget or expensive repair, it is necessary to determine the stage of damage, as the method of recovery depends on it. In the initial stages, when the varnish is just beginning to lose gloss or barely noticeable cracks appear, you can still do with gentle methods. However, if tear-covering before metal or formed swelling (craters), we are talking about deep corrosion.
For an accurate assessment of the condition, use a magnifying glass or a smartphone macro to consider the structure of the damage. Note the boundaries of the defect: if they are clear and sharp, it often indicates chemical burn or mechanical damage. If the edges are blurred and go into general matteness, most likely, there was a natural aging or oxidation.
| Stage of damage | Visual signs | Method of decision |
|---|---|---|
| Initial (Oxidation) | Loss of gloss, whitish plaque, roughness | Abrasive polishing, application of protective composition |
| Medium (Cracks) | A grid of small cracks ("web"), clouding | Deep polishing, possible local repainting |
| Critical (Detachment) | The polish climbed to the base, you can see the metal, bloating. | Complete cleaning, primer, painting of the element |
It is important not to confuse the ingrained contamination with the destruction of lacquer. Try to test the nail: if the nail clings to the edge of the crack, then the integrity of the structure is violated. If the surface is smooth but matte, it is most likely oxidation that is successfully removed. polish.
Useful advice: Do a scotch test on an inconspicuous area. Stick paint tape, tightly press and sharply rip. If there are particles of varnish on the sticky side, the adhesion is broken, and polishing will only worsen the situation, making the holes even larger.
Preparation for the restoration of the paint layer
If the diagnosis showed that the lacquer slur In large areas, serious surface preparation will be required before applying a new coating. Quality training accounts for 70% of the success of the entire work and guarantees the longevity of the result. The first step is always to thoroughly wash the body using a degreaser to remove silicones, bitumen and fat film.
This is followed by the process of mechanical cleaning of damaged areas. Use sandpaper carefully, starting with the P800-P1000 gradation to remove the bulk of the detached lacquer, and switching to the P1500-P2000 to create a smooth transition (risks). The main task is to remove all damaged material and create roughness for better coupling of new soil.
☑️ Checklist for surface preparation
Pay special attention to the protection of adjacent elements that will not be painted. Use a high-quality paint tape and cover film to paint or the dust didn't get on the glass, rubber seals and chrome parts. Even the smallest speck of dust under a new layer of varnish can spoil the entire appearance of the repaired part.
⚠️ Warning: Never ignore the degreasing phase. The remains of fingers, polish or wax will lead to the appearance of craters ("fish eye") on fresh varnish, and the work will have to be remade.
Technology of local repair and painting
The recovery process when tear-plateIt requires compliance with the temperature regime and time intervals specified by the manufacturer of materials. If you are doing local repairs, it is important to choose the right tone of the base, although when working with varnish (which is transparent) it is less critical than when painting the entire part. The main attention is paid to the application of soil-filler on the cleaned to metal areas.
The soil is applied in 2-3 thin layers with interlayer drying. Its task is to level the relief and ensure the adhesion of the varnish to the metal or old paint. After drying, the soil is also grinded with thin sandpaper (P2000-P2500) or scotch bright to keep the surface perfectly smooth. Only then can you start finishing the finish line. lacquer.
Lacquer is diluted strictly according to the instructions with a hardener. It should be applied with a spray gun with a pressure of about 1.5-2 atmosphere. The first layer is made thin, "dusty" to avoid leakage on vertical surfaces. The second and third layers are applied wet, with a characteristic gloss, providing the necessary thickness and depth of color.
The quality of the final result directly depends on the cleanliness of the room and the correctness of the dilution of components. Dust and draft are the main enemies when varnishing.
Pollination and protection of the updated coating
After the varnish has completely dried, which can take anywhere from 24 hours to several weeks for complete polymerization, the surface often requires finish polishing. Even with careful work, small irregularities, “shooting” or dust can remain. Polishing allows you to remove these defects and level the optical properties of the surface, making the transition between the old and new varnish invisible.
For polishing, compositions of different abrasiveness are used. First, it's applied. squirrel To remove micro-strains, then finishing paste to give a mirror shine. Work with a polishing machine should be careful, controlling the heating of the surface, so as not to overheat fresh varnish, which is still soft.
The final step is to apply the protective composition. It can be traditional wax, synthetic sealant or modern ceramic coating. Protection is necessary to ensure that the new varnish does not lose its properties under the influence of ultraviolet light and aggressive environment in the first months of operation.
Prevention and care of the car body
In order to avoid future situations where varnishIt is necessary to regularly take care of the body. Prevention includes not only washing, but also periodic renewal of protective layers. Twice a year, it is recommended to carry out a deep cleaning of the body with clay and apply a fresh layer of polymer or wax.
It is also important to remove aggressive contaminants in a timely manner. Bird droppings, tree sap, insect marks and bitumen stains should be removed as soon as possible. To do this, use special cleaners (bitum cleaner, tar remover), which dissolve the contamination without damaging the lacquer coating.
⚠️ Please do not rub a dry or dirty car with a rag. Sand caught between the fabric and the varnish works like sandpaper, leaving hundreds of microscopic scratches that eventually turn into a network of cracks.
Regular inspection of the body will allow to identify the beginning problems at an early stage. If you notice that the water has ceased to collect in drops and roll, and evenly spreads film - this is a signal that the protective layer has thinned and requires its restoration. Timely reaction will save the body from expensive repairs.
The Myth of the “Eternal” Ceramic Coating
Ceramics don't make varnish bulletproof. It only increases the hardness of the surface and hydrophobicity. A stone thrown into the hood at speed will damage both the ceramics and the varnish underneath.
Frequently Asked Questions (FAQ)
Can you paint the place where the varnish has worn out without a full repainting of the detail?
Local repairs are possible if the area of damage is small. However, it is more difficult to make the transition (extinguish the boundaries) on varnish than on paint, and often it is necessary to polish the entire part or even adjacent elements to eliminate the difference in shine.
How much does the varnish dry after painting before polishing?
Technical drying takes about 24 hours at a temperature of +20 ° C. However, complete polymerization and hardness set occur within 2-4 weeks. You can polish the "wet" varnish in a day, but you need to do it very carefully, without strong heating.
Why does the varnish come down around the emblems and moldings?
This often occurs due to moisture and detergent getting under the edges of stickers or decorative elements. The water stagnates there, causing corrosion or lacquer detachment. Also, the reason may be poor-quality surface preparation before installing dops.
Can I use regular sandpaper for cleaning?
You can use, but only special car sandpaper with silicon carbide, designed for wet grinding. A conventional building sandpaper can leave rough scratches that will be impossible to remove with polishing.
Do I need to be ground if the lacquer of tears to metal?
I will. The metal cannot be left open, as it will immediately begin to oxidize. It is necessary to apply acid soil (phosphate) for passivation of the metal, then acrylic filler, and only after that - the base paint and varnish.