SIKA Sikaflex-221, Black, Multi-Purpose Polyurethane Sealant & Adhesive, Permanent Elastic Seal, Sandable/Paintable, NSF Approved for Drinking Water, 10.1 (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.

This stuff is fantastic, especially for bonding hard to glue plastics. Be sure to wear gloves - it is very durable on skin!

Recommended by Chat for the exterior trim on my van. It worked perfectly, and sealed the joints where silicone had repeatedly failed.

I had the rubber trim come out of it's groove around the windshield of my motorhome. As I was only a few miles from my dealer, I went directly there. The tech put Sikaflex-221 into the groove, pressed the seal back into that groove and used tape to hold it in place while the Sikaflex cured. I've had no more problems. So, I ordered two tubes "just in case". And, like insurance, I have them but hope I never have to use them.

Simple use, no surprises, requires a longer cure time before painting

What can I say that hasn’t been said? Used this to install a fan on a campervan. It ain’t going nowhere and 100% confidence it will never leak.

I purchased this to seal mounting points for a Starlink antenna on top of our motorhome. This is a professional product and I expect it will prevent any water penetration.

If you need a really tough adhesive/sealant-this is it. It is a little hard to work with, but is about the best sealant I've ever used. Generally used for RV, boats, but i used it to repair the failing gasket on my refrigerator door, and it sealed it perfectly. Make sure whatever you are applying it to you intend to not take apart-it dries to very strong seal. it can be removed with a sharp utility knife or similar-but this, unlike so many of these products, is crappy water based which i generally find pretty useless for anything but gluing paper together. Even silicon-based caulks do not seal and last like this stuff. And it is equally strong indoors or out. The days of solid construction adhesive are over-except for this.