Effect of Alternative Paint Stripping Processes on the Fatigue Performance of Aluminium Alloys - Atmospheric Plasma De-painting

Typically, aircraft paint schemes lose their effectiveness for corrosion protection as well as cosmetic appearance every three to five years. As such, aircraft will undergo numerous removal and re-application cycles during their service lifetime to restore appearance, corrosion protection, or to enable inspection for fatigue cracks and corrosion damages. Current approved paint removal processes include chemical and abrasive media blasting. These processes yield high amounts of volatile organic compounds and generate large quantities of waste, which require proper disposal/treatment. They also have the potential to mask surface cracks and decrease the effectiveness of Liquid Penetrant Inspections (LPI). Concern over environment, safety and worker health with current paint removal processes has resulted in the enactment of new alternative removal processes during the past several years.

Atmospheric Plasma (AP) has the potential to replace conventional paint stripping methods used for military aircraft structures in the Canadian Forces. As part of a Department of National Defence green initiative for aircraft repair and maintenance, NRC had been tasked to investigate the potential of this novel technology.

In order for AP paint stripping to be accepted as an aerospace industry standard paint removal process, it must be thoroughly tested to demonstrate that it does not adversely affect the fatigue properties of the substrate. This paper investigates the effect of the AP paint removal process on fatigue crack nucleation and growth in aerospace aluminium panels.