Rapid Cure, Environmentally Acceptable Liquid Shim

Period of Performance: 04/29/2008 - 08/29/2010


Phase 2 SBIR

Recipient Firm

TDA Research, Inc.
12345 W. 52nd Ave. Array
Wheat Ridge, CO 80033
Principal Investigator


Liquid shims are filled, viscous resins used in the assembly of modern composite aircraft to fill small gaps between structural components and prevent stress concentration at fasteners. Current liquid shims provide excellent physical-mechanical properties but they must cure for eight hours before they can be machined. Unfortunately, this long cure time results in a bottleneck in aircraft assembly. To remove the bottleneck the U.S. Air Force is looking for a new fast-setting liquid shim. During previous work TDA Research, Inc. (TDA) developed a new shim curing chemistry that allows a 60-minute application time, but then cures to full hardness in only three hours. During this USAF SBIR Phase I project TDA employed its new chemistry to formulate an improved liquid shim, the formulation of which was optimized to meet a selected set of properties as specified by USAF and its contractors. In Phase II TDA will continue to optimize its shim to meet the complete set of requirements. TDA will produce a pilot batch of the optimized formula and conduct extensive performance and application tests. If results from the pilot batch are promising, TDA and its partners will begin full-scale manufacture and enter the qualification process.