Prevent bleed-through of materials and colors by using a sealer between the old surfaces and the new coatings. Failure to do so may mean that correction is needed by removal of the new finish, primer/surfacer use and refinishing.
Poor topcoat adhesion over repaired surfaces can be thwarted by using quality primer-surfacer. Use a surfacing material that is chemically compatible with your refinishing products.Start
at the finish
First examine the refinishing defect with an attempt to isolate the cause. Inspect the surface closely. Ask yourself important questions, such as, “Has your shop experienced similar complaints with refinishing efforts?” You see, the best cure for paint problems is preventing them in the first place. For example, a common complaint is dirt in the finish. The cause of dirty surfaces range from inadequate paint preparation, poorly maintained booth filters, poor booth sealing and shop air circulation. But also, are technicians working cleanly enough? Are you using a poor grade of masking paper? Is your spraygun adequately cleaned? Are finishes skinned over so the surface is dust-resistant before being taken from the spraybooth? Answer these questions before new problems arise.
Are you sure it’s dirt? Look closely. Small craters in the paint film present themselves if air bubbles are trapped in the wet paint film. These rise to the surface and burst. Improper spray gun setup, speed or surface distance during spraying can cause this. Occasionally you can sand these craters with 1,200 grit or finer sandpaper, then compound and polish to restore gloss. If not, sand to smooth and refinish the panel.
Paint runs, sometimes called hangers or curtains, are finish coats that fail to stick. There are many causes. First, you may be applying paint materials upon coats that are too wet, or coats without proper flash time between each application. You may move the gun too closely, or slowly, and runs may occur. Also, runs can happen if you overlap the patterns too tightly, spray using too low pressures or use an unbalanced spray pattern. Using a slowly evaporating thinner/reducer or too cold of a booth and vehicle surface temperature may cause this trouble.
Lifting occurs as solvents in your new coating attack the previous finish. While lifting is rarely a problem when repairing OEM finishes, if the panel being painted was previously refinished, you may experience a problem. Also, lifting occurs if you refinish enamels or urethanes that are not fully cured. The same may happen if you apply a flash or recoat when exceeding the maximum flash or recoat times, or an insufficient clearcoat film build occurs.
Wrinkling or shriveling of a finish, resembling the skin of a prune, happens when you pile on heavy, wet coats. This trouble, however, can also be created by spraying in hot and humid conditions, using too fast of a thinner/reducer, or putting a vehicle out in the hot sun too soon. And certainly, low spraygun air pressures and force-drying enamel without the recommended additives can also create this malady. If the surface is dry and trouble is slight, try lightly sanding the top surface until smooth. Allow the surface to cure and refinish. If the defect is severe, however, remove the topcoat from the wrinkled area and refinish it.
Poor topcoat flow, often called orange peel, can be caused by under reduction, low spray air pressures, too fast of a thinner or reducer, and heavy coats. To cure the problem, compound or polish to reduce the surface texture. If needed, sand smooth with 1,200 grit or finer sandpaper, then compound and polish to restore gloss. If this fails, sand the finish smooth and refinish. However, if you go through the clearcoat, strip to the undercoat and refinish.
Does a color bleed through? Experience teaches us that certain colors have less ability to cover undercoats. Solvent in the new topcoat sometimes dissolves soluble dyes or pigments in the original finish. This allows seepage into the new topcoat. To repair this malady, allow color to cure, then isolate the two with a sealer and refinish.
If the coating does not hide, the color was probably not mixed properly with a thinner or reducer. Or perhaps the substrate or primer/surfacer was not uniform in color and a sealer was not used. To correct the condition, remove the coatings, seal and refinish with proper reduction until hiding is achieved.
If the vehicle has been out of the shop for a time, cracks or lines of various lengths and widths in the topcoat finish may appear, resembling dried mud. These may be due to excess film thickness, previously razed/cracked surfaces, insufficient flash time, force drying with the spray gun, or too much hardener. Also, poor paint mix, prolonged exposure to sunlight, moisture and extreme temperatures can add to the problem. However, these are not sanding tracks. Using poor thinners, reducers or hardeners contribute to this cracking. If cracking occurs, we recommend stripping to remove all products and do a refinish again.
Flattening or dulling may be created by wax, oil or grease on the old surface. But also know that inferior solvents can easily cause this trouble. Other causes can be insufficient flash time between coats; excess thinning; compounding too soon; and improper drying room ventilation. If compounding doesn't remove the dullness, the area will have to be sanded to the undercoat, then dressed in new primer-surfacer before refinishing.
Water spots are circles with raised edges occurring when water contacts a finish that is not dry or cured. If these spots are present, first try wiping the surface with a damp cloth. Next, compound or polish. However, it may take judicious use of some 1,500- to 2,000-grit wet sandpaper, then some compound and polish to restore gloss. But remember, do not go through a clearcoat! If this light sanding won’t do it, then refinish it.
Quality control is critical in the paint shop. Defects will arise from time-to-time and should be tracked on a regular basis. To help improve overall performance, you should keep a record of problems as they occur to spot deficiencies in either product or technician performance. Any trends you find through this tracking will point towards improvements that will increase quality and customer satisfaction while reducing costly redos.
First examine the refinishing defect with an attempt to isolate the cause. Inspect the surface closely. Ask yourself important questions, such as, “Has your shop experienced similar complaints with refinishing efforts?” You see, the best cure for paint problems is preventing them in the first place. For example, a common complaint is dirt in the finish. The cause of dirty surfaces range from inadequate paint preparation, poorly maintained booth filters, poor booth sealing and shop air circulation. But also, are technicians working cleanly enough? Are you using a poor grade of masking paper? Is your spraygun adequately cleaned? Are finishes skinned over so the surface is dust-resistant before being taken from the spraybooth? Answer these questions before new problems arise.
Are you sure it’s dirt? Look closely. Small craters in the paint film present themselves if air bubbles are trapped in the wet paint film. These rise to the surface and burst. Improper spray gun setup, speed or surface distance during spraying can cause this. Occasionally you can sand these craters with 1,200 grit or finer sandpaper, then compound and polish to restore gloss. If not, sand to smooth and refinish the panel.
Paint runs, sometimes called hangers or curtains, are finish coats that fail to stick. There are many causes. First, you may be applying paint materials upon coats that are too wet, or coats without proper flash time between each application. You may move the gun too closely, or slowly, and runs may occur. Also, runs can happen if you overlap the patterns too tightly, spray using too low pressures or use an unbalanced spray pattern. Using a slowly evaporating thinner/reducer or too cold of a booth and vehicle surface temperature may cause this trouble.
Lifting occurs as solvents in your new coating attack the previous finish. While lifting is rarely a problem when repairing OEM finishes, if the panel being painted was previously refinished, you may experience a problem. Also, lifting occurs if you refinish enamels or urethanes that are not fully cured. The same may happen if you apply a flash or recoat when exceeding the maximum flash or recoat times, or an insufficient clearcoat film build occurs.
Wrinkling or shriveling of a finish, resembling the skin of a prune, happens when you pile on heavy, wet coats. This trouble, however, can also be created by spraying in hot and humid conditions, using too fast of a thinner/reducer, or putting a vehicle out in the hot sun too soon. And certainly, low spraygun air pressures and force-drying enamel without the recommended additives can also create this malady. If the surface is dry and trouble is slight, try lightly sanding the top surface until smooth. Allow the surface to cure and refinish. If the defect is severe, however, remove the topcoat from the wrinkled area and refinish it.
Poor topcoat flow, often called orange peel, can be caused by under reduction, low spray air pressures, too fast of a thinner or reducer, and heavy coats. To cure the problem, compound or polish to reduce the surface texture. If needed, sand smooth with 1,200 grit or finer sandpaper, then compound and polish to restore gloss. If this fails, sand the finish smooth and refinish. However, if you go through the clearcoat, strip to the undercoat and refinish.
Does a color bleed through? Experience teaches us that certain colors have less ability to cover undercoats. Solvent in the new topcoat sometimes dissolves soluble dyes or pigments in the original finish. This allows seepage into the new topcoat. To repair this malady, allow color to cure, then isolate the two with a sealer and refinish.
If the coating does not hide, the color was probably not mixed properly with a thinner or reducer. Or perhaps the substrate or primer/surfacer was not uniform in color and a sealer was not used. To correct the condition, remove the coatings, seal and refinish with proper reduction until hiding is achieved.
If the vehicle has been out of the shop for a time, cracks or lines of various lengths and widths in the topcoat finish may appear, resembling dried mud. These may be due to excess film thickness, previously razed/cracked surfaces, insufficient flash time, force drying with the spray gun, or too much hardener. Also, poor paint mix, prolonged exposure to sunlight, moisture and extreme temperatures can add to the problem. However, these are not sanding tracks. Using poor thinners, reducers or hardeners contribute to this cracking. If cracking occurs, we recommend stripping to remove all products and do a refinish again.
Flattening or dulling may be created by wax, oil or grease on the old surface. But also know that inferior solvents can easily cause this trouble. Other causes can be insufficient flash time between coats; excess thinning; compounding too soon; and improper drying room ventilation. If compounding doesn't remove the dullness, the area will have to be sanded to the undercoat, then dressed in new primer-surfacer before refinishing.
Water spots are circles with raised edges occurring when water contacts a finish that is not dry or cured. If these spots are present, first try wiping the surface with a damp cloth. Next, compound or polish. However, it may take judicious use of some 1,500- to 2,000-grit wet sandpaper, then some compound and polish to restore gloss. But remember, do not go through a clearcoat! If this light sanding won’t do it, then refinish it.
Quality control is critical in the paint shop. Defects will arise from time-to-time and should be tracked on a regular basis. To help improve overall performance, you should keep a record of problems as they occur to spot deficiencies in either product or technician performance. Any trends you find through this tracking will point towards improvements that will increase quality and customer satisfaction while reducing costly redos.
