G. Schmidt, D. D. Deppe, SMRC, Austin, TX
Wet installation of aircraft fasteners is a time-consuming, labor-intensive process involving the handling and disposal of environmentally hazardous sealant materials. With funding provided by the US Navy, Systems and Materials Research Corporation (SMRC) in partnership with PRC-DeSoto/PPG Aerospace is developing QwikSeal™, a self-sealing fastener technology designed to change the wet installation paradigm. QwikSeal will first be introduced using a derivative of PR-2001, an AMS3277-compliant two-part polythioether aerospace sealant manufactured by PRC-DeSoto. In the QwikSeal process the sealant is chemically modified to enable both resin and catalyst components to be pre-mixed and machine applied to the fastener. A proprietary nanocomposite frangible size coat covers the sealant acting both as structural support for the sealant and as a moisture barrier to prevent premature cure. Fastener installation stresses fracture the size coat, allowing the uncured sealant to flow through the hole as in a conventional wet installation. With the barrier coat gone, ambient moisture de-blocks the reaction and allows the sealant to cure normally. The QwikSeal process requires no changes to fasteners, holes, or tooling, and eliminates virtually all of the artisan’s handling of sealant products associated with fastener installation. Since the sealant volume applied is metered, only a small squeeze-out bead around the fastener’s head and tail remains to be wiped away, minimizing post-installation cleanup. QwikSeal has the potential to reduce manufacturing costs, speed production, improve quality and consistency, and reduce the hazmat footprint associated with wet installation of aircraft fasteners.
