

🔧 Seal it once, seal it right — the pro’s choice for lasting bonds!
SIKA Sikaflex-221 is a black, one-component polyurethane sealant and adhesive designed for permanent elastic seals on diverse surfaces including metal, plastic, and ceramics. It offers waterproof, age-resistant performance with NSF approval for drinking water safety. Packaged in easy-to-use cartridges, it hardens initially in 2 hours and fully cures in 5-7 days, delivering a flexible, sandable, and paintable finish ideal for professional and industrial applications.










| ASIN | B094G4WQVH |
| Best Sellers Rank | #1,863 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #205 in Adhesive Caulk #346 in Industrial Sealants #34,560 in Hardware |
| Brand | SIKA |
| Color | Black |
| Customer Reviews | 4.5 4.5 out of 5 stars (2,732) |
| Date First Available | February 28, 2012 |
| Full Cure Time | 5-7 Days |
| Global Trade Identification Number | 10033886005118 |
| Initial Hardening Time | 2 Hours |
| Item Form | Paste |
| Item Weight | 22.7 pounds |
| Item model number | 90893 |
| Liquid Volume | 10.1 Fluid Ounces |
| Manufacturer | SIKA |
| Manufacturer Part Number | 90839 |
| Material | Polyurethane |
| Maximum Gap Fill | 1 Inches |
| Number of Items | 24 |
| Product Dimensions | 12 x 8 x 12 inches |
| Surface Recommendation | Metal, Wood, Glass |
| Unit Count | 24.0 Count |
| Water Resistance Level | Waterproof |
O**A
Perfect for automotive use
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.
H**D
Great stuff
This stuff is fantastic, especially for bonding hard to glue plastics. Be sure to wear gloves - it is very durable on skin!
B**P
Excellent product.
Recommended by Chat for the exterior trim on my van. It worked perfectly, and sealed the joints where silicone had repeatedly failed.
T**S
Worked for me as a good automotive seam sealer.
Worked great for my 1990 Ford E250 van gutters and sealing up some seams that after all this time the original seam sealer had deteriorated. No more leaks! Stuff is not easy to get off your skin so wear protective stuff when applying it.
L**G
Simple, no surprises, longer cure time before painting
Simple use, no surprises, requires a longer cure time before painting
D**.
Holds like all get out
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.
A**L
This stuff works!
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.
B**K
About the best sealant/adhesive, period.
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.
H**M
Very good
K**Y
Great brand always works
C**N
Excelente producto
A**R
Good quality
T**S
I needed some good adhesive to attach solar panels to my camper and a lot of places recommended this stuff so I decided to give it a shot. It applies just like any other adhesives, pretty straight forward, and when used as instructed it creates a very nice bond between two materials. I was wary at first driving down the highway on first test run paranoid the wind was going to rip them off, and after a couple summers with highway driving, I am now confident in the quality of the item. It does what it is intended for. Would, and have, bought this again.
Trustpilot
3 weeks ago
1 month ago