Teach you how to avoid problems in the use of sealant

In the process of using sealant, we often encounter some problems. First of all, we will analyze the irregular foaming problem on the surface of weather resistant adhesive, because of what reasons, and how to deal with it.

Usually there are several reasons for foaming problems: (1) environmental reasons: (1) when the joint is wet, foam rod and other accessories are damp, it is easy to appear foaming phenomenon; (2) when sizing substrate surface temperature is too high will cause sealant bubbles; (2) the reasons for manual operation: (1) discontinuous or the moving speed of the glue gun is inconsistent with the speed of the glue, resulting in uneven sizing, easy to wrap part of the air, the formation of hollow bubbles; (2) Improper construction, the surface of the closed cell foam rod is broken, and the foam rod releases gas.

According to the above reasons, we should handle the problem of foaming in accordance with the requirements of the "silicone sealant use process guide" for construction, avoid sizing in the humid, high temperature exposure and other environments; In addition, standardize sizing personnel operation; And the use of appropriate foam rod, it is recommended that the diameter of the foam rod is about 120% of the width of the glue seam.

In addition to the bubbling problem, the surface of weather resistant adhesive will also appear irregular draping problem. The drum phenomenon mainly appear in the metal panel curtain wall, aluminum curtain wall, for example, as a result of the aluminum plate heat bilges cold shrink coefficient is higher, at a time when seasonal temperature difference between day and night is too big, sealant not completely cured before cannot fully adapt to the large displacement, sealant will appear because of the aluminum plate tensile compression irregular phenomenon of the drum.

In view of this phenomenon, we should avoid the peak of poly temperature when applying sealant to aluminum plate and aluminum plastic plate curtain wall project, and choose the construction after 17 PM in the west and southeast. And when the surface temperature of the substrate is below 4℃ or higher than 50℃, it is not suitable for construction; In addition, it is recommended that the construction be divided into two times. The thickness of the first glue is controlled at about half of the depth of the gap. The next day (the specific time depends on the curing degree of the colloid), and then the second glue is played. Here we recommend the selection of Sheng Group silicone weather-resistant sealant can significantly improve the phenomenon of drum.

In addition, in the use of single-component sealant, too late to modify, often produce crust, this is because the curing of single-component silicone rubber is greatly affected by environmental temperature and humidity. Under high temperature, the drying speed of the sealant surface is accelerated. After sizing, the exposure time in the air is too long, and the colloidal surface is dry. Therefore, in order to avoid sizing later than modification, in the construction environment, a simple table dry time test, and then the construction, in the table dry before modification can avoid this phenomenon.