Vishay Precision Group - Document - 0 - Strain Gage Installation Checklist: Composite and Plastic Materials - Composites typically have one of two surface conditions. The tooling side is usually smooth requiring slight roughening to give the adhesive something to bite into. The non-tooling side is usually rough due to the layup of either woven or filament wound or random orientation carbon fiber filaments. This kind of surface typically needs to be as filled to make it smooth enough for bonding. The gage length is dictated by the desired averaging. With woven composites, that would typically be 3-5 cycles of the weave. Since composites are typically poor conductors of heat, pre-cabled gages or gages with preattached leadwires are highly recommended. For long-term dynamic loading conditions, strain gages with maximum fatigue life may be required.