Sika Sikaflex-221 - White - Multi-Purpose Polyurethane sealant/Adhesive - Creates Permanent Elastic Seal - Sandable/paintable - Non-Corrosive - 10.1 fl oz (Pack of 24)

I used Sikaflex to adhere a roof wing to the back windshield of my car, and I’m seriously impressed with how well it worked. The bond is incredibly strong and feels permanent once cured. I let it set for about 24 hours before driving, and even after months of highway speeds and temperature changes, the wing hasn’t budged at all. The application was pretty straightforward, it has a thick, tacky consistency that gives you enough working time to position everything correctly before it starts to set. I’d recommend taping or clamping the part in place while it cures, because it does take a while to fully harden. Once cured, it’s flexible enough to handle vibration and movement, which is great for automotive use. One thing to note: this stuff is messy. It’s sticky, and once it gets on your hands or paint, it’s not easy to remove. Wear gloves, mask off surrounding areas, and have some cleaner or mineral spirits ready. Overall, Sikaflex delivered exactly what I needed, a strong, weatherproof, and vibration resistant bond that’s holding my roof wing securely in place. It’s not the cheapest adhesive, but it’s worth it for the strength and reliability.

Before I retired, my company was excellent at ceiling water leaks. Sika was the best product in areas exposed to ultraviolet light. I recently used it when installing a new skylight on my RV. Knowing that it’s difficult to clean up, I blue taped all edges and had rags with solvent nearby. The job went very smoothly, I was impressed how easily it adhered and spread evenly. Cleanup turned out to be no problem for me.

Sikaflex 221 was easy to work with and performed well in my project. It adhered strongly, cured into a solid bond, and left a clean finish. So far, it has held up well and given me confidence in the result, sealing even with heavy rains.

This stuff is phenomenal and a Saving Grace it cures very hard but yet subtle

Product works great on my RV, but this last tube I purchased had an “expiration” date that’s picky 3 months from the time of delivery. I’m not sure what happens after it expires, but why would Amazon send something like this so close to the expiration date? I keep a tube with me for RV repairs.

Great sealant for my box truck build, strong but flexible

Great product, needed this to reseal around some pipes and wires at the underbelly of my travel trailer. Wear gloves, this stuff is messy. Looks and feels like it will hold up to the test of time.

I used this to attach my solar panels to the fiberglass roof of my van. Being a hero i also put one 1/2 inch screw in each. I let it sit overnight and didn't leave town for three days. They haven't moved a millimeter