Advanced Technologies for Discrete-Parts Manufacturing

Wet installation of fasteners offers proven corrosion protection and fuel sealing in aircraft structures, but it''''s a labor-intensive, messy, hazmat-laden process whose quality can vary significantly from fastener to fastener. Under a Navy SBIR Phase II, SMRC has developed a proprietary process called QwikSeal® for pre-coating fasteners with cure-blocked sealant, then overcoating the pre-applied sealant with a moisture-impermeable nanocomposite size coat. On installation – potentially weeks or months later - the size coat franges, allowing the uncured sealant to coat the hole. Ambient moisture absorbed by the sealant unblocks the reaction and initiates normal cure. Though interest among aircraft manufacturers and maintainers is extremely high, there are concerns for inadvertent installation of fasteners whose sealant has prematurely cured. A premature cure indicator (PCI) is, therefore, a prerequisite to widespread adoption of QwikSeal. SMRC proposes development of selectively-tuned molecular probes which when imbedded in the cure-blocked sealant or size coat layers will change color on exposure to thiol groups, a very early and direct sign that the sealant is about to prematurely cure. Successful PCI development, not funded under any existing/proposed initiatives, could clear the way for large-scale entry of QwikSeal into the aerospace marketplace through PPG Aerospace, SMRC’s commercialization partner.