This test method covers the determination of the char density profile of a charred ablator. The total thickness of the char and degradation zone must be larger than the machining thicknesses required. Density variation throughout a charred ablator material is determined by successively measuring, machining, and weighing a sample of known size to obtain the density of the material removed by machining. The apparatus required for this method includes a laboratory balance capable of measuring to the nearest ten thousandth gram, and a machining technique capable of removing material in increments as small as a thousandth mm.

1.1 This test method covers the determination of the char density profile of a charred ablator that can be used with the following limitations:

1.1.1 The local surface imperfections must be removed, and the char must be able to be machined off in a plane parallel to the char-virgin material interface before the density profiles can be determined.

1.1.2 The char must be strong enough to withstand the machining and handling techniques employed.

1.1.3 The material should have orderly density variations. The total thickness of the char and degradation zone must be larger than the machining thicknesses required.

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.