Yellowing in powder coating: Identifying causes and effective remedies
Yellowing in powder coating can lead to undesirable colour changes and impair the quality of the end product. It is therefore crucial to identify the causes of these problems and take appropriate countermeasures. Based on the recommendations of GEMA, we present common causes and optimisation options below.
1. Overheating during the baking process
Excessive baking temperature or baking time can lead to yellowing. Recommendation: Check the oven temperature and baking time and adjust them according to the powder manufacturer's specifications.
2. Powder coatings unsuitable for high temperatures
Some powder coatings are not designed for high temperatures and may yellow when overheated. Recommendation: Use heat-resistant powder coatings that are suitable for the specific requirements of your application.
3. Contaminants in the oven
Residues or contaminants in the oven can generate vapours that cause yellowing. Recommendation: Clean the oven regularly to remove deposits and ensure a clean environment for the baking process.
4. Insufficient air circulation in the oven
Uneven air circulation can lead to temperature differences that cause yellowing. Recommendation: Ensure that the air circulation in the oven is even to ensure a constant temperature distribution.
Conclusion
By observing these points and regularly maintaining your powder coating system, you can effectively prevent yellowing and improve the quality of your coatings. Further detailed information can be found on the official GEMA website: GEMA Tips & Tricks – Yellowing.
