Common Finish Defects and How to Solve Them
Our goal is that by following the tips and guidance we have provided throughout this training you will be unlikely to have finish quality problems but inevitably their will come a time when you run into a finish appearance issue. Will cover the most common finish problems and their causes as well as link to a great resource for you to see these issues first hand and better identify them.
Solvent pops
Solvent pops will look like small bubbles that start bubbling up from your painted product and will have a hollow center. Solvent pops will appear much like small pimples in the finish of your paint job. Solvent pops are caused by a few common issues. One of the biggest causes of solvent pops can be to high of a cure temperature which causes solvents to flash off to quickly and can result in air being trapped within the paint which when escaping to rapidly will create a bubble. The solution for this is to reduce the cure temperature and follow your technical data sheets. A second common cause of solvent pops can be spraying to close to the surface of your product which can result in excessive solvent being sprayed on your surface creating an increased likelihood of a solvent pop.
Orange Peel
A second common finish defect is orange peel which is where the finish you have applied is not smooth in appearance and can appear like crinkles in the finish. This is usually due to not using the proper spray equipment for your paint, not setting the air to fluid pressure properly on a spray gun, using to large of a tip with your spray gun, or not thinning your paint properly. The best way to avoid orange peel problems is to do a fast pass test spray to see how your spray pattern looks like (see below for an example of a high quality finish vs orange peel finish).
Dirt and Dust in the Finish
Dirt and dust in a finish will be similar to solvent pops but will appear less consistently in the finish. Dirt and dust in the finish is usually due to having a dirty painting environment (not using a paint booth with filtered doors or not keeping the floors of your paint booth clean).
Fish Eyes
Fish eyes appear like a shiny appearing surface defect and result due to oil contaminating your finish whether from your compressed air or due to migrating into the finish of your finish during drying. To eliminate fish eyes you will want to make sure your compressed air is being filtered properly and ensure that you do not have contaminating oil products nearby your booth (like a silicon product). These will be the common causes of fish eyes.
Paint cracking and lifting
If your paint is cracking or lifting from the surface of your product this is typically due to inadequate surface preparation. Whether from not sanding the surface sufficiently prior to application, not sandblasting the surface prior to application, or not selecting a proper coating system for the surface your coating. The way to fix a problem like this is to ensure you prep the surface according to the technical data sheets and have selected a coating system designed for your substrate.
These are common paint finish defects .
Best practices to eliminate defects
- Follow the technical data sheets for how much to thin your coating, how much to apply, and equipment options to apply the coating
- Use your spray equipment properly
- Ensure your compressed air is clean of impurities
- Ensure your booth is clean
Further resources
http://www.linetec.com/paint/Common_Defects_Causes_&_Preventionl.pdf