1.Silicone structural sealant is not bonded to profiles and glass
The structural glue is not bonded to the profile and glass or the bonding is poor. There are several reasons for this.：
①The construction is not standardized, for example, the adhesion test has not been done before the construction, the substrate has not been cleaned as required, and the cleaned glass has not been closed immediately.Solution: Ensure that the substrate is cleaned and the construction is carried out in accordance with the requirements of the specification；
② During the construction process, the method of cleaning or applying the primer liquid does not conform to the construction process.Solution: Clean according to the "secondary rag method” and proceed to the next step of construction within 1 hour; the primer should be thin and uniform, and the next step of construction should be carried out within half an hour. For the specific operation process, please refer to "Baiyun Online" "Construction Silicone Structural Glue Coating Primer Process"；
③Substrate material problems, such as differences in different batches of substrates, etc.Solution: Strictly use materials that are consistent with the adhesion test.In the production process, different batches of materials need to be randomly tested for on-site adhesion.；
④The two-component structural glue has uneven mixing during the glue injection process.Solution: Pass a butterfly test to confirm that components A and B are evenly mixed before glue injection；
⑤The amount of component B of the two-component structural adhesive is too much or too little, which exceeds the manufacturer's allowable proportion range.Solution: Pass the pull-off time test before glue injection to confirm that the proportion of glue in components A and B is within the range specified by the manufacturer.；
⑥The ambient temperature is low, resulting in slow initial bonding speed, or short maintenance time, and non-bonding during glue cutting and testing.Solution: Increase the ambient temperature for use and maintenance (especially for single components).
2.Silicone structural sealant curing slowly
The curing of silicone structural adhesives is slow. According to many years of technical service experience, most of them are due to the following three types of reasons.：
①The curing speed is slow due to low ambient temperature and humidity.Solution: Improve the use environment and maintenance ambient temperature, such as using confined spaces to set up a greenhouse, air conditioning to heat up, etc. To keep the maintenance ambient temperature at 10-40℃, and the humidity at 50~90%；
②The curing speed is slow due to low non-ambient temperature and humidity.Solution: Confirm whether the proportion of components A and B is normal through the pull-off time, and the proportion of component B can be appropriately increased within the range of the manufacturer's allowable adjustment ratio to speed up the curing speed.
③The silicone structural adhesive has expired or has its own quality problems.Solution: Check the production batch number of the glue, confirm whether the glue is within the shelf life, and choose silicone structural glue with guaranteed quality and brand.
3.The width of the structural adhesive is not enough: the actual width is less than the design width
There are two main reasons why the width of the structural adhesive is not enough：
①the injection glue is not full.Solution: The glue injection is continuous and uniform, and the nozzle can extend into at least one-half of the depth of the seam.After the glue injection is completed, it should be trimmed.
②the size of the seam assembly is too small.Solution: Assemble the seams in strict accordance with the design and size of the glue joints.
4.Structural glue colloids have bubbles or holes
There are two main reasons why structural colloids have bubbles and holes：
①the injection glue is not full.Solution: Same as above.
②the gluing machine is mixed with air, and dense air bubbles appear in the colloid.Solution: To ensure that the gluing machine is trouble-free, and the air should be drained before use after changing the barrel.
The above problems are all problems that seriously endanger the safe application of structural adhesives.During the construction process, it is necessary to ensure that the size of the structural adhesive bonding meets the design requirements, the glue injection is full, and there are no bubbles or holes.It is hoped that customers should avoid these problems during the glue process and ensure the safety of the curtain wall.
Silicone structural sealants are essential to the quality and safety application of concealed curtain walls.Choosing "good glue“ is a prerequisite for ensuring quality and safety, and ”good use" glue is an important process to realize the safe application of hidden frame curtain wall.