Summer is here! High temperature, sun exposure is coming soon! In such an environment, architectural silicone sealants often have some problems, such as foaming, especially neutral glass glue. Why is it easier to foam when glued in summer? How to avoid it?

There are basically three reasons for the foaming of glue in summer, with specific solutions.

1. Wet base material causes foaming of glue injection
It is rainy in the south in summer. If the construction is carried out outdoors after the rain, the glue will be injected directly inside the joint if it is still wet. When the sun shines on the substrate and the glue joint, the temperature inside the joint will rise, and the moisture in the glue joint will evaporate, which will cause the uncured The relatively soft glue joints bulge and blister, and sometimes the polyethylene foam pads are wet and can also cause glue joints to blister.

Countermeasures: Don't blindly seek progress during construction, wait until the interface is dry, and then inject glue to avoid it.

Second, the substrate temperature is too high
During high temperature in summer, the surface temperature of the construction substrate will be higher, and when the silicone adhesive is cured, the temperature of the bonded material should not exceed 50 °C.
Once the glue is injected when the surface temperature of the substrate exceeds 50 °C, it will cause foaming of the glue seam, and the above situation will be encountered when the weather-resistant caulking of the metal sheet curtain wall is used.
In hot summer, when the sun is exposed to the metal plate, especially the surface temperature of the aluminum plate will reach 80 ℃, at this time, the glue injection can easily cause the glue seam to foam.

Countermeasures: Construction should be done in the evening or cloudy days to avoid foaming due to high substrate temperature.

3. Uncured glass glue is exposed to the sun
Generally, silicone glue cannot be exposed to the sun before it is cured, especially if it is exposed to the sun just after the glue is injected, it will cause honeycomb bubbles to appear inside the glue seam, which will cause the external bulge of the glue seam. It will be more obvious when using silicone glue.
In hot summer construction, this situation is easy to occur. It is recommended to avoid sun exposure when injecting glue to alleviate the foaming phenomenon.

Countermeasures: inject glue on the west or north side of the building in the morning, and inject glue on the east or south side of the building in the afternoon. After the glue is injected in this way, the glue has been cured for a period of time, and the surface has been crusted. When exposed to the sun again, it has a certain resistance and will alleviate the blistering phenomenon.