How to eliminate the effects of outgassing in powder coating
How to Eliminate the Effects of Outgassing
There are some different methods that have been proven to eliminate this problem:
1. Preheating the Part:
This method is the most popular to eliminate the problem of outgassing. The part to be coated is preheated above the cure temperature for at least the same amount of time to cure the powder to allow the entrapped gas to be released prior to applying the powder coating. This solution may not eliminate all the outgassing if the part has an enormous amount of entrapped gasses, where the gas just keeps being released, no matter how much or how often you preheat the part.
2. Seal the Part Surface:
This method requires the application of a material under pressure that is used to seal the entrapped gasses within the substrate, therefore,eliminating the outgassing from occurring entirely. Search for companies that specialize in impregnating/sealing casting technologies to obtain more information.
3. Change the Curing Technology:
A change in curing technology to IR or IR/UV can eliminate the outgassing problem since the only the part surface is heated to cure the powder coating. In this case, the part substrate is not entirely heated, a necessity to release of the entrapped gasses.
4. Powder Formulation:
The coating powder used for your specific application can be changed by your powder supplier to have enhanced flow characteristics. This means that the powder will stay in a liquid form for a prolonged period of time during the cure process. This allows the entrapped gasses in the substrate to escape when the coating is still liquid and flow over the pinhole, creating a smooth and hole-free surface.Please refer to our anti-gassing powder coating .
5. Change or Improve the Substrate:
Substituting the casting material with one that has less gassing issues can be a graceful solution. Working with your casting supplier to add vents or chills in particularly problematic areas is another area that can improve the substrate or eliminate the outgassing.
6. Eliminate the Contamination:
Parts that have surface contamination are best corrected by eliminating of the contaminant. Identify the contaminant and remove it prior to powder coating and this problem will go away.
7. Control the Coating Film Thickness:
If the outgassing problem is caused by excessive film build on the part, then the easiest way of correcting the problem is to reduce the film thickness. If a heavy film thickness is required for the application, then select a different coating material or apply the coating using two thinner coats.