A paint defect analysis is essential if you're having trouble with the quality of your paint finish. There are a number of common defects you may be experiencing, and any one of them could indicate a number of different problems. In order to determine the solution for the defect, you must first determine the cause, and that’s where an analysis can help. Here are 9 signs to watch out for in your paint finish that indicate you should look into paint defect analysis.
1. Peeling Paint
When paint doesn’t adhere properly to a substrate, it will soon start to peel away from the surface and flake off. The most likely cause is some sort of contamination, either in the paint or on the substrate, that prevents a proper bond between the paint and substrate. This can also be caused by excess solvent in the paint.
2. Dirt in the Finish
One of the most common problems you likely face with paint defects is finding dirt in the finish.
This is because dirt is lightweight, airborne, and can easily make its way into the finishing process before, during, and after painting – especially in the electrostatic systems commonly in use today. The paint, the substrate, and the environment can all be contaminated.
3. Film Variation
When film is distributed unevenly, you'll see variations in the finish quality and even color of the paint across the substrate. Uneven film builds can lead to other finish problems, including:
- Runs and sags
- Mottling and color mismatch
- Orange peel
- Blistering, peeling, and craters
- Solvent pop
4. Cracks in the Finish
Crazing is when multiple multi-directional small cracks form in the finish, and this often causes the surface of the paint to look like a river or lake bed that’s dried out. The major cause is thermal force that causes the substrate and primer, primer and basecoat, or basecoat and clearcoat to expand and contract at different rates and it is often associate with excess film build.
5. Runs and Sags
Runs, sags, and drips are almost always caused by an excess of paint being applied to an area, often in the overlap of spray passes, and the solution is making sure that paint is applied evenly across the entire surface to control the quality of the finish.
Blistering of all sorts, up to and including solvent pops, are similar defects but they may have unique causes. For instance, if there's foreign material on the substrate (from insufficient cleaning) or in the paint, it can lead to blistering—areas where the paint covers the surface, but does not adhere properly. This can also occur when the film is too heavy and the surface skins over before the solvent has a chance to evaporate out of the lowest layers of paint. The solvent trying to escape can lift the paint off the surface—like a balloon. This same phenomenon can occur when excess solvent is added to the paint and there is insufficient time to get it all out in the curing process. In these instances, the extreme is solvent pop, which happens when the evaporating solvent creates greater pressure than the surface of the paint can withstand and the surface “pops”.
7. Orange Peeling
Just as the name suggests, orange peel is a reference to the dimpled finish—like the surface of an orange—that appears when excess solvent evaporates, too much paint is applied, the wrong spray gun setup is used, or the paint is applied at the wrong angle—just to name a few.
8. Color Variations
Color variations are often attributed to defects in the paint itself, but can also be caused by a number of application factors, many of which result in uneven film distribution, such as:
- Paint impact velocity
- Inconsistent fluid delivery
- Non-uniform spray pattern
- Electrostatic problems
- Atomization problems
- Inconsistent metallic flake laydown
Spitting can occur when the gun or bell doesn’t atomize the paint properly as a result of dirt (or other contamination), surges, inconsistent atomizing pressure, shaping air, and more. This can result in splatter, bumps, and paint globs in the finish. This can also be caused by condensation—created by the cooling of the compressed air used to drive the gun or bell—getting into the paint stream.
Many paint issues today, including the ones discussed here, can be caused by temperature at critical areas of the paint system. No matter which of these common paint finish defects you're struggling with, Saint Clair Systems recommends a free paint defect analysis to help you locate the source of your paint issues. An analysis will help you determine exactly how, where, and when the problem is occurring, and allow you to identify and implement solutions that will fix the issues and optimize your paint application system and create a predictable outcome.
Learn more about identifying and preventing the cause of automotive paint problems. Get your free copy of our Orange Prevention eGuide.