Test for Tack-Free Time of Elastomeric Sealants

Test for Tack-Free Time of Elastomeric Sealants

There are several reasons why it is important to perform the Test for Tack-Free Time of Elastomeric Sealants. First, it ensures that the sealant has cured sufficiently to provide the necessary adhesion and flexibility. Second, it allows for the determination of the appropriate curing time for the sealant, which is critical for ensuring that it is ready for use. 

The test method typically involves the following steps:

1. Preparation of the substrate: The substrate must be clean, dry, and free of any contaminants, such as dust, dirt, or oil. The substrate should be non-porous, such as glass or metal, to prevent the sealant from penetrating or adhering too strongly to the substrate.
2. Application of the sealant: Apply a small amount of the sealant to the prepared substrate using a standardized application method, such as a caulking gun or a putty knife.
3. Curing of the sealant: Allow the sealant to cure under controlled conditions, such as a specific temperature and humidity. The curing time will depend on the type of sealant used and the environmental conditions.
4. Testing for tackiness: Once the sealant has cured sufficiently, test it for tackiness using a standardized test method, such as ASTM D907, ASTM C661 or ASTM C679. The test method typically involves lightly touching the surface of the sealant with a gloved finger or a specially designed tool and observing whether it sticks or leaves a mark.
5. Recording the tack-free time: The tack-free time is the amount of time it takes for the sealant to lose its tackiness and become solid enough to touch without it sticking to a finger or tool. Record the tack-free time based on the test results and any other relevant information, such as the type of sealant used and the environmental conditions.

Video 01: Test Method for Tack-Free Time of Elastomeric Sealants