Some do-it-yourself types enjoy trying their hands at automotive painting. When doing so, it is important for you to be able to recognize and correct some of the things that cause the most frequently occurring automotive paint problems.
Fisheyes
When you spray on a coating of primer or paint, fisheyes might result. These are crater-like circular openings that may appear either while you are spraying your primer or paint on or directly after it has been applied. This problem is usually caused by spraying your primer or paint onto a surface that has contamination from wax, silicone, grease or oil. The easy way to avoid this is to make certain that you use a wax and grease remover while you are preparing to paint.
Wrinkling or lifting
This problem occurs when a paint layer shrivels up while you are applying a new finish or while the new finish is drying. This happens when solvents in your new finish attack the old finish, causing the lifting and wrinkling. This can happen when you are recoating urethanes or enamels without allowing them to fully cure or when you wait beyond the maximum dry time during your application.
Bleeding
Bleeding occurs when you have a discoloration that appears in your topcoat color. It happens when the fresh topcoat’s solvent dissolves pigments that are soluble in the old finish. This may be repaired by allowing your stained topcoat to fully cure. Then, spray a sealer over it and reapply the color.
Dulling or hazing
This happens when the gloss or shine of the finish dulls as it dries. There are many different causes, but it often results when you don’t allow the undercoat to adequately dry or cure.
Crow’s feet
These are cracks that sometimes appear in topcoats. Like dulling, this may result from several different causes. The most common reasons this might occur include the following:
- Using a blowgun to dry your primer
- Applying too thick of a film coat
- Insufficient drying time between coats
- Using too much catalyst or hardener in your primer or paint
To fix this, you must strip away all of the cracked paint film and redo the job.
Sags
Sags are extremely common for do-it-yourself types. These occur when you hold your paint gun too close to the surface, double coat a spot or move it too slowly. It also sometimes happens when you reduce an area too much or trying to paint when it is too cold. To avoid this, hold your paint gun at a perpendicular angle, keep it far enough way from the surface and move it in fast, even strokes.
Orange peeling
An orange-peeled surface has the appearance of an orange peel. This is normally a result of using too low of pressure or not reducing the paint enough. If it is not too severe, you might be able to correct it with wet sanding using 1200-grit sand paper followed by buffing or respraying of the surface. Always thin your paint according to the instructions on the label and do not overcoat your surface.
Feather-edge lifting
Also known as edge mapping, this paint problem results from solvents in topcoats penetrating through areas of the undercoats. It looks like a wrinkling around an area that has been repaired. To avoid this, make certain to use a primer surfacer that is water-based, two-component or another sealer to create a good barrier layer. When this problem happens, you will need to either remove the problem area or smooth and sand it.
Air trapping
This problem occurs when tiny air bubbles rise to the surface of the paint and pop, leaving craters behind. To avoid this, make certain that your spray gun is adjusted properly, use the correct air pressure setting and keep your gun an appropriate distance away from the surface. You can correct this problem by sanding the area with 1200-grit sandpaper and then polishing it.
Sand scratches
These are streaks, lines or marks that appear in your paint film. They are the result of not properly sanding the body or primer, filling in scratches with primer or sanding basecoat or single-stage finishes before you clear them. You can fix these by letting it cure and then re-sanding the problem area before refinishing it.
Cracking
With this problem, cracks of varying lengths form in your finish. This results when the film of your undercoat or topcoat is too thick. It can also happen when you are painting over a cracked surface or if you use too much hardener. This requires stripping and refinishing to fix.
Peeling
When you lose adhesion between your paint and its substrate, sections of the color may separate away. To avoid this, make sure that you prepare the surface properly by properly sanding, cleaning and using the correct primer.
Pinholing
Pinholes occur when body fillers contain air bubbles that are then exposed while you sand the area, leaving small holes behind in the surface. This results from the improper mixing of your hardener with the filler. If you use too much of the hardener, pinholing is even likelier to occur.
Debris in your paint
It is important to try to paint in an environment that is as dirt- and dust-free as possible. Wetting down the floor both before you spray your paint and between each coat can help. You should also make certain that the surface itself is thoroughly cleaned before you begin.
Softness
This happens when your paint is soft after it is dry, making it susceptible to water spotting and fingerprints for days after your paint job. This happens when you spray the undercoat or topcoat too heavily or don’t give sufficient drying time between the coats.
Mottling
Mottling refers to a streaked appearance that might appear in transparent or metallic finishes. It can be caused by many different things, including using a spray pattern that is not balanced, tilting the gun, over-thinning or spraying on your clearcoat before the basecoat has completely dried.
Grit
Grit refers to the problem of solid particles of varying sizes being embedded in the surface of your paint. This can happen when the paint or primer is not strained or stirred properly. It can also happen if you are using a can of old paint. It is possible to fix this issue by allowing it to cure and then sanding and re-spraying.
Pimpling
These are swollen areas that appear in the surface months or weeks after your paint job. They result from moisture that is trapped under the surface of the paint. To avoid this, try to paint in a dry area, using a dehumidifier if the area in which you live is one with high humidity.
Discoloration
This can happen when you paint over body filler or glazing putty, and it appears as a yellow stain in the topcoat. It can be caused by using either too much or too little hardener in your filler, not mixing the filler completely or priming before you’ve allowed the filler to cure completely.
Blushing
In areas with high humidity levels, blushing can happen when the evaporation of the solvent reduces the surface temperature below the dew point. This can cause moisture in the paint layer, leaving a clouded look to the surface. You can fix this problem by adding retarder to the paint mixture and recoating the area. Choosing a high-quality reducer that is designed for the conditions in which you will be painting can help to avoid this problem.
The best way to avoid automotive paint problems is to follow the manufacturer’s recommendations at all times. Always make certain to give the layers the appropriate time to cure, use high-quality products and avoid cutting corners to achieve the results that you want.