MIL-PRF-3420 §4.5.3 Copper U-Bend Panels

Copper U-bend test specimens used in MIL-PRF-3420 §4.5.3 (Compatibility with Copper). This test method uses three panels of copper (ASTM B152), each measuring 1/2" x 3" x 1/16". The copper is polished with 240 grit AO to remove pits and irregularities from all surfaces. Each panel is then bent into a U shape with a 1/4" bend radius and 1/12" distance between the side walls. 
 
Metaspec provides these copper specimens as polished flat strips (not bent) and as polished U-bend specimens.