Since silicone sealant is a chemical building material, its curing reaction relies on moisture in the air. In hot and humid summer conditions, excessive high temperature and heavy humidity will greatly affect the storage stability, construction operability and final curing effect of sealants. Therefore, proper storage and standardized construction are essential for high-quality sealing work.
01 Packaging and storage of sealants
Silicone sealant cures by reacting with moisture. If exposed to continuous high temperature, rain and heavy humid air, the product inside the cartridge may start premature curing, which shortens shelf life and causes blockage or poor extrusion during construction.
In hot and humid seasons, sealants should be stored in cool, dry and well-ventilated warehouses, away from direct sunlight and rainwater immersion. If the sealant packages get wet accidentally, move them out of humid environment immediately, remove outer cartons, dry the cartridge surface and place them indoors. Use these products as soon as possible after inspection.
02 Correct method of sealant application
Before construction, please pay attention to the following points:LOCHAO silicone sealant is suitable for clean substrate with ambient temperature between 4℃~40℃ and relative humidity of 40%~80%.It is not recommended to carry out sealing construction beyond this temperature and humidity range.
Outdoor temperature rises sharply in summer, especially for aluminum curtain wall projects, where the surface temperature of substrates can be much higher than air temperature. When the site temperature and humidity exceed the recommended range, you need to perform a small-area test on site first, then do peeling adhesion test to verify stable bonding and no adverse phenomena before large-scale construction.
During construction, follow the steps below
01 Construction sequence of structural sealant (curtain wall structural sealant, hollow glass double-layer structural sealant etc.)
Clean the substrate
High temperature in summer accelerates solvent volatilization. You need to control cleaning operation efficiently to guarantee cleaning quality. Grease, dust and dirt on bonding surface must be fully removed.
Apply primer (if necessary)
High temperature and humidity make primer easy to hydrolyze and lose activity when exposed to air. Inject sealant right after primer application. Reduce the exposure time of primer to air, and small turnover packaging bottles are preferred.
Sealant injection
After injecting structural sealant, do not apply weatherproof sealant to outer side at once. Otherwise, the curing speed of structural sealant will be seriously slowed down.
Trimming
Finish trimming immediately after sealant injection. This helps sealant fully contact with the interface side to form tight bonding.
Recording and marking
Complete on-site recording and marking right after construction.
Maintenance
The assembly must stay under static and stress-free conditions for enough curing time to ensure structural sealant achieves designed bonding strength.
02 Construction sequence of weather-resistant sealant & door and window sealant
Preparation of glue joints
Backer rods contacting sealant must be intact. High temperature in summer may cause blistering if backer rods are damaged. Meanwhile, compatibility check between substrate, backer rod and sealant is required.
Clean the substrate
Clean dust, oil and contaminants inside glue joints thoroughly.
Apply primer (if necessary)
The substrate surface must be fully dry. High temperature and humidity will cause primer hydrolysis. Apply sealant promptly after priming, minimize air exposure time of primer. Small-volume bottles are recommended.
Sealant injection
Summer brings frequent thunderstorms. Never inject sealant until glue joints are completely dry after rain.
Repair
High temperature shortens the available repair window. All repair work must be finished right after sealant injection.
Maintenance
Do not subject the sealant joint to large displacement at the early maintenance stage.
