5.1 This test method is useful for establishing the integrity of composite rod. The presence of voids, cracks, and hollow fibers are considered detrimental to the structural integrity of the composite and causes reduced electrical resistance and increased current leakage.

5.2 A perfect composite would be flaw-free, and there would be no possibility of wicking. Composites of this type are virtually nonexistent, as there will typically be entrapped air in the resin developed during manufacturing, occasional hollow fibers, and occasional cracks due to thermal stresses.

5.3 This test method is intended to provide a tool for measuring the extent of wicking in a composite over very short lengths of material for comparative purposes. The presence of wicking over 1 in. (2.54 cm) lengths will not necessarily imply that the composite will perform unsatisfactorily for its intended end-use. Therefore, interpretation of test results shall be made carefully.

5.4 This test method was developed as a technique for estimating quality and consistency of pultruded rod and bar stock, which is a composite of resin and all-roving reinforcement. This test method will be useful for a manufacturer to determine whether any gross changes in quality have taken place due to process or raw material changes as the manufacturing process also affects the quality of the product.

5.5 Since the results of this test are so sensitive to sample size, penetrant type, penetrant used, viscosity, duration of test, and other factors, no attempt to arrive at or recommend development of a specification for these materials has been made. A specification shall be negotiated between supplier and end user and such specification shall be made with great care.