ASTM C712-14(R2021) pdf free download

ASTM C712-14(R2021) pdf free download.Standard Test Method for Bubbling of One-Part, Elastomeric, Solvent-Release Type Sealants
1. Scope
1.1 This test method covers determination of the degree of bubble formation or surface blistering in one-part, elastomeric solvent-release type sealants when exposed to elevated tem- peratures. 1.2 The subcommittee with jurisdiction is not aware of any similar ISO standard. 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions—Refer to Terminology C717 for definitions of the following terms used in this test method: compound, elastomer, elastomeric, sealant, solvent-release sealant, substrate, and standard conditions.
4. Significance and Use
4.1 The type and amount of solvent used in these sealants can sometimes give rise to surface bubbling and blistering problems. The substrate used, whether porous or nonporous, will also have an effect. Although blistering is often caused by misapplication, this test method is useful in differentiating between a sealant that develops an acceptably smooth surface and one that may have blistering tendencies.
5. Apparatus
5.1 Plates, thin aluminum, approximately 3 in. (76 mm) wide by 5 in. (127 mm) long by 0.012 in. (0.30 mm) thick. 5.2 Blocks, prepare cement mortar, as described in Termi- nology C719 to the following size: approximately 2 in. (51 mm) wide by 4 in. (102 mm) long by 1 in. (25 mm) thick. N OTE 1—Other substrates such as brick, cast stone, marble, stainless steel, etc., may be specified either in place of the standard materials specified in 5.1 and 5.2 or in addition to them. 5.3 Frame, flat, rectangular, of 1 ⁄ 8 -in. (3.2-mm) steel or brass, with an opening of 1 in. by 3 3 ⁄ 4 in. (25 mm by 95 mm) and outside dimensions of approximately 2 in. by 4 3 ⁄ 4 in. (51 mm by 121 mm). 5.4 Spatula, steel, with knife edge. 5.5 Oven, forced-draft type, having a temperature controlled at 122 6 3.6 °F (50 6 2 °C).
6. Test Specimen
6.1 Take the test specimen from a previously unopened container as received from the sealant manufacturer.
7. Procedure
7.1 Prepare three test specimens on each substrate as fol- lows: Center the frame on the test substrate and carefully fill it with compound, avoiding air pockets. Strike off the surface of the compound flush with the frame, to a uniform thickness of 1 ⁄ 8 in. (3.2 mm). With the spatula, cut all around the outside edge of the compound and lift the frame straight up and off. 7.2 Condition the specimens for 48 h at standard conditions. 7.3 Place the specimens in the oven at 122 6 3.6 °F (50 6 2 °C) for 72 h.7.4 After heat exposure, allow the specimens to cool at 73.4 6 3.6 °F (23 6 2 °C) for 1 h. 7.5 Examine each specimen for surface gas bubbles and blisters.
8. Report
8.1 For each substrate, report the total surface area covered by the bubbles or blisters, estimated to the nearest 0.1 in. 2 (65 mm 2 ). The area of bubble formation may be estimated by superimposing on the specimen a glass or clear plate ruled into 1 ⁄ 2 -in. (13-mm) squares.
9. Precision and Bias
9.1 The precision and bias calculations for this test method are based on the results of four laboratories testing three materials using five specimens per test. The results are given in Table 1. 9.1.1 At 95 % confidence level a variation of as much as 0.59 in. 2 can be expected within a laboratory and 0.60 in. 2 between laboratories. This is based on three materials being tested by four laboratories.