Out-gassing is a common occurrence when working with powder coating ovens. While it is certainly a nuisance, there are certain steps that can be taken to ensure that it does not get repeated.
Out-gassing is the release of trapped gases from powder coating during the curing process. The problem related to out-gassing is that it can form pinholes in the coating. When exposed to moisture or atmospheric contaminants, these pinholes can be filled with corrosive materials, which can degrade the component.
Out-gassing takes place due to a few important reasons:
- Casting: When the powder coat is melted and poured before applying, it can cause air to be trapped in the coating, which can lead to out-gassing.
- Thick Coating: If the first pass coating has a great amount of thickness, out-gassing can take place.
- Contamination of the Application Surface: If a substrate has contaminants like oil, mold, dirt, and grease, and then powder coated, then it can lead to out-gassing.
Solutions for Out-gassing
The problem of out-gassing can be prevented by following a few simple methods:
- Clean the Part: The simplest solution is to clean the part before the powder coating and curing process takes place. This will help remove any contaminants on the component, thus eliminating the possibility of out-gassing.
- Apply a Primer: The part surface can be sealed by first applying a primer to the application substrate. This can help eliminate the problem.
- Preheat the Component: Pre-heating the part can help get rid of contaminants. It can allow all the trapped gases to be released before the curing process is performed in a powder coating oven. However, the preheat temperature has to be higher than the curing temperature.
- Improve Powder Characteristics: The flow characteristics of the powder can be improved. This can ensure that the powder coat will remain in its liquid form for a longer period during the curing process. This will give time for the gases to be released.
- Apply Two Coat Layers: If one layer becomes too thick, then a simple solution is to apply the coat in two layers before placing the component in industrial ovens. This will help control the coat thickness, thus preventing out-gassing.
The problem of out-gassing can create multiple problems and steps should be taken to avoid it. The above mentioned solutions can help eliminate the problem and ensure the delivery of clean, well coated, and cured components.