In construction and renovation, the combination of aluminum alloy and glass is key to achieving both aesthetics and functionality. However, the core element connecting them—silicone sealant—if chosen or used incorrectly, can lead to poor adhesion, corrosion of the aluminum, water leakage, and even safety hazards.
Don't worry. By mastering the following three key points, you can easily make the right choice.
1. Core Principle: Choose "Neutral," Avoid "Acidic"
This is the most important rule: Never use acidic silicone sealant.
Reason: Acidic sealants release acetic acid during curing, which corrodes the aluminum alloy surface, causing discoloration, loss of gloss, and severely compromising the bond.
Correct Choice: Always choose a silicone sealant clearly labeled "Neutral Cure" on the packaging. It is non-corrosive to metals and is the safe prerequisite for bonding aluminum alloy and glass.
2. Selection by Application: Distinguish Between "Structural" and "Sealing"
Depending on whether the bonded joint bears load, we need to choose sealants with different properties:
Structural Bonding — Use "Structural Sealant"
When to use? When the bond needs to bear the glass's dead weight, wind pressure, or vibration (e.g., structural glazing facades, structural skylights, large load-bearing glass railings).
Which sealant to choose? Must use "Structural Silicone Sealant." These products have extremely high strength and can bear loads long-term like a structural component.
Non-Structural Sealing — Use "Weatherproof Sealant"
When to use? Primarily for filling gaps, waterproofing, weatherproofing, and fixing (e.g., door/window installation, glass partitions, adhesive attachment of decorative strips).
Which sealant to choose? Choose a "Neutral Cure Silicone Weatherproof Sealant." It has good elasticity to accommodate the thermal expansion and contraction of the materials and is UV resistant, making it suitable for outdoor use.
3. Three Key Application Factors: Ensuring Success
Correct installation is the other half of the success:
Surface Cleaning is Key: Thoroughly clean the bonding surfaces of the aluminum alloy and glass with acetone or isopropyl alcohol to remove all oil and dust, and ensure they are completely dry.
Application Technique Must Be Correct: For deeper joints, first insert a backer rod as a backup material. Then apply the sealant evenly and continuously, ensuring full contact between the sealant and both substrates.
Allow Time for Curing: Silicone sealant needs time to reach full strength. After skin formation (about 30 minutes), continue supporting and fixing the components for at least 24 hours, avoiding movement or vibration.
Summary
In simple terms, for bonding aluminum alloy and glass, remember: Prefer "Neutral Cure" sealant, use "Structural" for load-bearing applications, use "Weatherproof" for sealing, and always "Clean the Surface" before application.
By following the guidelines above, you can select the most suitable and safest silicone sealant for your project, ensuring its long-term durability.