Ultra-comprehensive paint FAQs and solutions.

In paint repair operations, common paint problems such as orange peels and bubbles can mostly be avoided if the correct method of operation is used. However, due to the more process of repair paint work, the chance of paint problems is still very high. Analysis of the cause of the problem, usually due to putty layer or primer layer mishandled, paint process lack of control, poor working environment, and paint composition deviations and other

. If a problem is found during the painting process, the operation can be stopped and appropriate measures taken immediately, depending on the problem, or it can wait between the end of the painting process before processing.to analyze the paint defects and treatment methods commonly found in painting operations.
1, moist foaming
evenly distributed hemp-like small bubbles, different sizes, in very humid and hot conditions prone to appear. These bubbles disappear when the air humidity decreases and the paint film becomes flat.
(1) cause
(1) paint, medium coating, primer and substrates do not adhere to each other enough, may lead to foaming.
(2) paint is relatively permeable. Under very humid and hot conditions, water penetrates into the paint film in liquid form and then through the paint film in the form of steam, thus forming moist bubbles.
(2) Correction Method
(1) Only dry grinding can be used in wet weather to keep compressed air dry and to ensure that the spray surface is completely dry before spraying.
(2) paint parts should not be placed in a hot and humid environment until they are completely dry.
(3) When the bubble is not cracked, you can sit still and wait for the moisture to evaporate to restore the paint film to its original condition, in severe cases must be thoroughly polished and re-sprayed, paint to bare metal re-spray is the best choice.
2, contaminated foaming
also known as bubbles or "tweezers", that is, the surface of the paint layer irregular foaming conditions.
(1) cause
(1) is mainly substrate contamination, no proper cleaning and preparation before painting.
(2) contamination from gas supply pipes or spraying tools.
(2) Correction Method
(1) Clean the spray surface and completely remove substances such as wax, grease and polish.
(2) ensure the cleanliness of tools such as compressed air, air supply pipes, and spray guns.
(3) if the tweezers have been produced, gently polish the surface, take care not to wear through the paint film, re-spray. If the condition is serious, it should be polished to bare metal and re-sprayed.
3,
paint sprayed, paint has foreign objects or dirty spots, dust or dirt is wrapped in paint film.
(1) cause
(1) spraying workshop is not clean, for example, the interior of the paint room is not laid filter cotton, filter cotton on the roof has not been replaced for a long time.
(2) compressed air is not clean, spray operators are not wearing special work clothes, spray surface is not clean.
(3) paint is not effectively filtered before spraying.
(2) Correction method
(1) to keep the paint shop clean, regularly replace the paint room filter cotton, strictly prohibited in the paint room grinding atomic ash.
(2) ensure that compressed air is clean and change the filter regularly. Clean the spray surface with compressed air or a dust cloth before spraying.
(3) properly sealed to store the paint, the paint should be fully stirred before spraying, and filtered for use.
(4) If there are already dust spots, polish until smooth and recoyed. For lighter dust points, fine sandpaper should be polished and polished.
4, feather-like edge cracking
paint film in the feather-like edge around cracking, in a very short period of time after spraying paint will appear.
(1) causes
(1) excessive dilution or use of inferior thinners.
(2) used coarse sandpaper in polishing the beveled edges, and the paint was not properly treated before the paint, the solvent in the paint entered the sandpaper trace erosion paint film.
(3) the paint sprayed on the inner coating is too thick or too wet, and the solvent in the paint does not have enough time to evaporate outwards.
(4) old paint film or previously patched defects appear, or use too much atomic ash.
(2) correction method
(1) correctly polish the feather edges, smooth and smooth transition, to avoid any sharp corners and layers.
(2) according to the specific situation of the workshop, according to the requirements of the use of thinners and the use of the correct dilution ratio.
(3) do not blow dry sprayed paint film, as this can only achieve dry surface.
(4) when cracking occurs, the surface of the paint film should be polished and re-sprayed.
5,
also known as silver powder flowering, which is a common problem in silver powder and pearl primers. The paint film shows signs of being knocked, with some dark circles surrounding light silver powder or shades of color. If it is in primer paint, this phenomenon is often not discovered until varnish has been sprayed.
(1) Cause
(1) Silver powder is a combination of different pigments and aluminum powder, in the thick or humid paint level spray silver powder paint, will make silver powder in silver powder can not be leveled, thus forming a pattern.
(2) When the temperature is too low and silver powder is sprayed, silver powder will remain in a humid or liquid state for a long time, and the silver powder will accumulate in piles.
(3) When applying silver paint, if the air pressure used is low, or the gun is closer to the surface plate, then when the paint surface reaches the work surface, too little solvent volatility will lead to the formation of a damp paint film, easy to lead to the phenomenon of marking.
(4) used a diluent that evaporates very slowly, or is used excessively.
(2) Correction Method
(1) Dilute the silver paint as required and master the correct spraying techniques, such as the distance between the spray gun and the spray surface and the speed at which the spray gun moves.
(2) Do not apply excessive thick wet paint. When necessary, raise the temperature of the paint workshop appropriately and extend the time between the paint films.
(3) If the markings have been produced, it is recommended to re-spray with the correct dilution ratio and construction techniques. If the markings are produced in a primer coated with varnish, the paint film needs to be peeled back and repainted.
6, the paint surface subsides
the patched area subsides, the paint surface forms a "lake" shape appearance.
(1) Cause
(1) When spraying multi-layer paint, the previous paint surface is not thorough enough.
(2) atomic ash subsidence, but spraying low-gloss medium primer is not easy to find, and spraying high-gloss paint, paint subsidence phenomenon appears.
(3) sprayed with multiple layers of wet paint in a short period of time, and the inter-layer stationary time between primers and finishes was not long enough.
(2) Correction method
(1) All layers of atomic ash should be completely dry, especially when the weather is bad or the temperature is low.
(2) do not thickly coat the wet paint film coated with primer and paint, should be in accordance with the requirements of the control of inter-layer sit-in time.
(3) Do not dry the wet paint film surface by blowing, as this may result in only the surface drying, and the solvent inside the paint film is not fully volatile.
(4) When the lacquer film subsidence occurs, polish to a smooth surface and re-spray.
7, pinhole
also known as pits, that is, the appearance of paint film on the dense small holes.
(1) cause
(1) the compressed air used for spraying contains moisture, or the wrong type or amount of thinner is used in the paint.
(2) excessively thick wet coating, or force drying with a hairdryer, or spray workshop temperature is too high or too low.
(2) Correction Method
(1) The discharge valve of the air compressor that provides the gas source should be opened daily to allow the aggregated moisture to flow out.
(2) to avoid excessive thick coating, medium film thickness to ensure proper solvent volatility. Do not blow dry wet paint surfaces, which may cause surface cortification or solvent retention in the membrane.
(3) strictly follow the drying rules. Select the correct thinner and dilute it according to the recommended proportion.
(4) use the correct spray gun and adjust the pressure to ensure good atomization.
(5) If the pinhole occurs, polish until flat and repaint.
8, powdered
paint pigment particles are no longer affected by the adhesive, paint film surface appears powdery, passivated, faded and lost luster.
(1) Cause
(1) Pigment particles in the paint age or loose due to prolonged exposure of the paint film to strong sunlight and other climatic conditions, resulting in powdery peeling of the paint surface.
(2) used the wrong thinner to impair the durability of the paint layer.
(3) paint is not mixed evenly.
(2) correction method
(1) select the appropriate thinner and mix the paint well before spraying.
(2) light powder can be polished to remove, more serious cases need to be polished with crude wax, heavy powder needs to be re-patched spray.
9, acid erosion
appearance of rough spots, spot edges because of acid erosion into the paint film, sometimes the paint film color changes and make the paint uneven.
(1) causes asphalt on
(1) pavements, insect carcasses and industrial pollutants and other acidic substances corrosion, or in the maintenance of vehicles spilled on the paint surface of the brake fluid and other grease, will cause acid erosion.
(2) the paint film is cleaned before it is dry, or an unsuitable cleaning agent is used.
(3) the old paint film contains contaminants or polishes, and before re-spraying without thorough treatment, can cause acid erosion of the new paint film.
(2) Correction method
immediately remove the above-mentioned contaminated substances from the paint surface, polish the acid erosion with crude wax, in severe cases, need to be polished and re-sprayed.
10, stripes
also known as plaques or shadows. The surface of the lacquer layer appears the color of the difference, often in parallel, silver powder paint and pearl paint appear the highest chance.
(1) cause
(1) spray gun spray paint fan-shaped mid-edge paint too much, and the middle paint is too little, the possible cause is too much compressed air pressure, spray gun dirt or nozzle adjustment is improper, should reduce compressed air pressure or narrow spray fan.
(2) spray technology is poor, the distance between the spray gun and the spray surface often changes or the spray surface overlap is uneven, the spray gun and spray surface should always be consistent in the spray process, and maintain 50% overlap.
(3) paint is not diluted properly and the thinner is not added according to the process requirements.
(2) Correction method
If the stripes have appeared, wait for the paint to dry, after re-spraying a coat of paint, should ensure that compressed air pressure, gun adjustment and paint thinner ratio is correct.
11, orange peel
also known as poor leveling. The paint film produces an orange-like lumpy effect, mainly due to poor leveling. The so-called poor leveling refers to the spray gun spray paint particles through atomization to reach the spray surface, can no longer flow between each other, so as not to smooth the paint film surface.
(1) cause
(1) improper adjustment of the spray gun leads to poor paint atomization. Improperly adjusted nozzles, excessive fan-shaped spraying of paint, or excessive distance from the spray surface of the spray gun can cause the paint to become overly dry before reaching the spray surface. When this happens, the foggy paint particles that reach the spray surface will remain in the same shape formed by the nozzle, resulting in a rough surface structure. Ideally, atomized paint particles should be kept properly moist when they reach the spray surface, allowing them to flow and mix with each other to form a smooth surface structure.
(2) the proportion of inferior thinners or incorrect thinners. Insufficient thinners or the use of rapidly evaporating thinners can cause paint particles to become overly dry before they reach the spray surface.
(3) temperature is not right. When the ambient temperature of the spray operation is too high, the paint particles are already overly dry in the process of reaching the spray surface, resulting in poor leveling.
(4) is not properly dried. The forced drying process is carried out before the paint particles on the spray surface are leveled, which increases the chance of orange peel appearing in the paint film. In multiple sprays, if the previously sprayed paint film is overly dry, the solvent in the repainted paint is absorbed by the underlying layer, and the paint particles that are sprayed again cannot be leveled.
(5) paint is not evenly stirred. Paint after a long period of storage will appear the phenomenon of bottom precipitation, before spraying should be fully stirred evenly, otherwise there will be parts of the dry uneven, resulting in the phenomenon of orange peel.
(2) correction method
If the orange peel has been produced, when the paint film is completely dry, polished with appropriate thick wax. In severe cases, polish the orange peel surface with fine sandpaper to a smooth surface, wax and polish it, or re-spray it.
12, dry spray
is also known as over-spraying or dry spray dissolving, the surface of the paint presents a powdery or rough paint effect. Usually in the roof shed and bonnet and other parts of large-scale spraying, in the position of the gun is more prone to dry spray phenomenon.
(1) Cause
when spraying compressed air pressure is too high, spray workshop or paint room ventilation system is not working well or the ambient temperature is too high, the use of incorrect gun nozzles or improper construction process.
(2) Correction method
when spraying, the compressed air should be adjusted to the appropriate pressure and the air flow in the spray shop should be avoided.
the spray technology and adjust the spray gun correctly.
if the climate is hot and dry in the spraying environment, slow-drying thinners should be used appropriately.
if the primer appears dry spray phenomenon, should use a cleaning cloth with thinner wipe, or wait for the paint to dry after polishing. If.