Sikaflex 521 sealant grey
Sikaflex 521 sealant grey
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Sikaflex®-521 UV is a weather-resistant, permanently elastic STP adhesive/sealant with a broad adhesion spectrum (including metal, plastic, and wood). We often supply this sealant with roof installations, as it is very suitable for watertight sealing of rivets and profiles.
What do we use this sealant for?
- Watertight sealing of rivets during roof installation
- Sealing of aluminum Z-profiles on campervan roofs (mechanically fastened with rivets)
- Elastic sealing for penetrations and connections (internal/external)
Tip: we use / supply Sikaflex®-521 UV (optionally) with our Aluminum Z-profiles (set of 4), because an elastic seal handles vibrations and roof movement better.
Key properties
- Resistant to weathering and aging (suitable for outdoor use)
- Adheres to many substrates without special pre-treatment
- Permanently elastic – absorbs movement and vibrations well
- Isocyanate- and solvent-free
- Low odor and often paintable (always test beforehand)
Please note: surface preparation remains important. Always ensure a clean, dry, and grease-free surface.
Important: this is not a structural adhesive
Sikaflex®-521 UV is intended for sealing and light adhesive/sealing applications, but not for structural bonding on a camper roof.
- Do not use for bonding plastic spoilers
- Do not use for bonding corner brackets
- Do not use as the sole mounting for solar panels on the roof
Why not? With solar panels, the roof is constantly working (temperature, wind, vibrations). For safe, long-term roof mounting, a structural adhesive with the correct system build-up (and often primers) is required — to prevent detachment and damage.
Application (brief & practical)
- Substrate: clean, dry, and grease-free
- Application temperature: approx. 5 °C to 40 °C
- Skin formation: approximately 30 minutes (depending on conditions)
- Curing: via air humidity (slower in cold/dry conditions)
Finish within the skin formation time and, if in doubt, test adhesion/compatibility beforehand.
FAQ
Can I use this to glue solar panels?
No. For solar panels (spoilers/corner brackets), we recommend a suitable structural adhesive. Sikaflex®-521 UV is intended for sealing and elastic finishing.
Why do you supply this sealant with Z-profiles?
Z-profiles are mechanically fastened with rivets. This sealant is ideal for making rivets and profiles watertight while maintaining elasticity.
Does this adhere to aluminum and common camper materials?
Yes, it adheres well to many substrates (including metal, various plastics, and wood), often without primer. A clean surface and good preparation remain crucial.
Next step (are you unsure about the right sealant?)
Are you unsure whether you need a sealant or a structural adhesive for your application? Please contact us – this will help you avoid wrong choices and unsafe situations.
Safety and processing information: always follow the product information sheet and, if in doubt, work with a test area.
This product text is intended as a practical guideline. For exact technical data and application advice: consult the datasheet.
