How to avoid silicone sealant cracking?

Usually we may have heard some news about the cracking of silicone adhesive. Sometimes the adhesive cracks in the middle, sometimes it cracks on both sides, and sometimes it cracks in the middle and both sides at the same time. We don’t know the specific reason for the cracking. People are troubled.

When the silicone sealant is completely cured for a period of time, it may crack due to its own reasons or external forces, which directly affects the bonding and sealing effect of the sealant. The bonding ability and sealing performance are very important to the effectiveness of silicone sealant. Generally, there are three states of sealant cracking: cohesive failure in the middle crack, and bonding failure in which the bonding surfaces at both ends are cracked. and the hybrid destruction common to both.

The main reasons that cause silicone sealant to crack are as follows:

1. The joint design is unreasonable. For example, the sealant joint is too narrow and it is difficult to apply sealant; or the sealant application process is not standardized and the bonding and sealing are not in place.

2. The sealant is improperly selected, and the displacement capacity cannot meet the requirements for joint displacement.

3. The actual plate size installation deviation is too large.

4. The sealant shrinks severely during the early curing process, the joints deform too much, and the joints shift.

5. Three sides are bonded, resulting in limited displacement ability of the sealant.

6. The sealant thickness does not meet the specification requirements, is too thin or has uneven thickness, resulting in damage or bonding damage during use.

7. If the ambient temperature is too high or too low during construction, the curing will be stretched by external forces, causing the colloid to crack and unable to form a round sealant layer.

8. The sealant is not used within the validity period.

So how to avoid colloid cracking?

1. During construction, you must be familiar with the relevant construction base materials and base material compatibility issues. Based on the construction purpose and goals, choose silicone sealants from big brands with good quality reputation and guaranteed quality;

2. Before construction, take a small amount of samples to conduct a compatibility test before construction to verify whether the compatibility between the sealant and the base material is good and the bonding and sealing effect of the sample;

3 Before construction, clean and remove water from the base material in advance, and wait until the base material is dry and clean before construction can begin. Ensure that the sealant can bond well with the base material;

4. After gluing, ensure that the construction site has a good temperature and humidity environment, and ensure a good maintenance environment and sufficient maintenance time in the later period.