At this writing, aerospace quality extruded transparent polycarbonate material is not available in thicknesses greater than 0.5 in. (12.7 mm). When a requirement exists for sheets thicker than 0.5 in. (12.7 mm), two or more sheets are fusion bonded together to form a single sheet of the desired thickness.

The structural integrity of the completed transparency depends on the integrity of the fusion bond. This test applies torsional shear loads to measure the structural integrity of the fusion bond. This test method is considered more reliable and more reproducible than shear tests in tension or compression.

1.1 This test method determines the shear yield strength F_sy and shear ultimate strength F_su of fusion bonds in polycarbonate by applying torsional shear loads to the fusion-bond line.

1.2 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.