This test method can be used to obtain the gel time of resin squeezed from prepreg tape or sheet material. This test is a useful measure for material acceptance.

The gel time will vary with the test temperature. The temperatures specified in this test method are two of many temperatures often used in processing epoxy prepreg material. If other test temperatures are used, this is to be clearly noted as indicated in 9.1.2.

Gel time is not recommended as a measure of outline (unacceptable degree of cross-linking). Use Resin Flow Test Method D3532, or Dynamic Viscosity Practice D4473.

1.1 This test method covers the determination of gel time of carbon fiber-epoxy tape and sheet. The test method is suitable for the measurement of gel time of resin systems having either high or low viscosity.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.2.1 Within the text, inch-pound units are shown in brackets.

1.3 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.