Epoxy resin systems used in the repair of composite skin sandwich panels for durable, rigidwall, relocatable shelters must have a combination of mechanical property levels and environmental resistance that will assure long-term durability of the skins and the skin-to-core adhesive bonds when exposed to severe climatic exposures. In addition, these epoxy materials must have processability characteristics that permit their use in a variety of repair scenarios and environments.

Intended Use—Epoxy systems conforming to this specification are intended for use in the repair of honeycomb panels at the maintenance field level. The material is intended for use with SAE-AMS-C-9084 glass cloth.

This is a procurement control document for the procurement of the epoxy system and designers shall be aware that the test values specified herein are based upon tests performed with specific glass-resin composite adherends and shall not be used for design data.

Epoxy systems covered by this specification are not intended for use in production bonding of sandwich construction.

This specification covers the requirements for an epoxy resin system intended for the repair of sandwich panels for durable, rigidwall, relocatable structures. It must be usable in a field environment and shall not require the use of special equipment such as autoclaves or presses. The epoxy system covered by this specification shall be usable for simultaneous impregnation of a wet-layup composite skin and bonding of that skin to a substrate honeycomb core. The inspection and testing of the epoxy system shall be classified as qualification tests and quality conformance tests. The following test methods shall be performed to conform to the requirements specified: tensile lap shear strength; apparent horizontal shear strength; and flatwise tensile strength.

1.1 This specification covers the requirements for an epoxy resin system intended for the repair of sandwich panels for durable, rigidwall, relocatable structures. It must be usable in a field environment and shall not require the use of special equipment such as autoclaves or presses. The epoxy system covered by this specification shall be usable for simultaneous impregnation of a wet-layup composite skin and bonding of that skin to a substrate honeycomb core. The material shall withstand exposure to temperatures from −54 to 93°C (−65 to 199°F) and high relative humidity, and also the combination of stress, temperature, and relative humidity that are expected to be encountered in service.

1.2 The values stated in SI units are to be regarded as standard where only SI units are given or where SI units are given first followed by inch-pound units; where inch-pound units are given first followed by SI units, the inch-pound units are to be regarded as the standard.

1.3 The following safety hazards caveat refers only to the test methods described in this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.