ASTM C419-94

The method of preparation of test specimens of mastic thermal insulation coatings can have an impact upon values obtained during testing. Testing laboratories should follow this practice to help ensure the reproducibility of test methods for which a cured sheet or film of a mastic thermal insulation coating is required.

1.1 This practice covers the preparation of specimens of mastics and coatings in the form of cured sheets or films that may be used in other procedures for evaluation of physical properties.

1.2 Three procedures are described for casting and curing (Note 1) mastics and coatings of all types for thermal insulation.

Note 1--The term "cure" is used primarily to denote the condition that develops as the result of loss of volatile matter but also to denote possible subsequent changes in chemical or physical properties due to crosslinking.

1.2.1 Procedure A is intended to provide a specimen of controlled thickness applied to insulation, and equivalent in other respects to that obtainable under field application conditions. The thermal insulation intended for field use may be specified as the backing.

1.2.2 Procedure B is intended to provide a free-film specimen of controlled thickness having smooth surfaces on both sides. This type is required for some types of physical testing.

1.2.3 Procedure C is intended to provide a free-film specimen of controlled thickness having one smooth surface (as field applied).

1.3 The procedures of this practice are not intended for the evaluation of application properties. These are covered in Test Methods C461 and Guide C647.

1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 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.