Powder contamination is a common occurrence, but is nearly 100% preventable.
There are two main categories of contamination, Cross Contamination of the raw powder itself or surface/substrate contamination (see Figure 1). Both contaminant forms produce a less than desirable finish outcome.
Following a good housekeeping regimen will go a very long way to prevent a powder cross contamination problem. Keep your booth clean, cleaning after each color change will prevent excessive buildup of powder particulates on the walls and ceiling of your spray booth. Consider using a fluidized powder hopper which keeps powder isolated during use. Box feed systems expose the powder to airborne contaminants and humidity. Using a thorough pre-treatment process for parts will help alleviate part surface contamination.
Final check:
- Keep your work area clean
- Use a fluidized hopper whenever possible
- Keep the ambient temperature down to around 70- 80°F
- If possible, try to keep the ambient humidity down
- Reduce the likelihood of airborne particles
- Store leftover powder responsibly
- Follow a part pre-treatment regimen
Nearly 100% preventable!
Figure 1. Typical outcome from surface contamination of the substrate. If your powder coating contains significant defects, your customers/clients will be less than pleased. Save your time and wallet by following these best practices.