Sikaflex 221 One-Component Adhesive Sealant
Sika Sika
  • Sikaflex 221 One-Component Adhesive Sealant

Sikaflex 221 One-Component Adhesive Sealant

Sikaflex 221 bonds well to a wide variety of substrates and is suitable for making permanent, high adhesive strength elastic seals. Use 221 on substrate materials wood, metals, metal primers and paint coatings (2c or 2 part systems), ceramic materials and plastics.
IN STOCK - Available for pickup  
$195.99 / cs
List:  $238.80 / cs
You Save:  $42.81
Aluminum Gray  
IN STOCK - Available for pickup  
$10.92 / ea
 The item was added to your wishlist.
 The item was added to your shop cart.
Tech Spec Product Info User Generated Content

Sikaflex-221 is a high-quality multi purpose non-sagging 1-component polyurethane sealant that cures on exposure to atmospheric humidity to form a durable elastomer.

Key Features

  • 1-Component Formulation (1C)
  • Elastic
  • Low Odor
  • Resistant to aging and weathering exposure
  • Non-corrosive
  • Can be painted over
  • Can be sanded
  • Bonds well to a wide variety of substrates
  • NSF-approved for incidental food contact and potable water.
  • Sealant type: Polyurethane  Temperature: -40 to 195 F 
    Time until tack free: 60 min  Full cure time: 60 min to 10 days 
    Tensile Strength: 260  Hardness: Shore A 40-45 
    Specific Gravity: 1.27  Elongation: 500% 
    BRAND: Sika
    Material: Polyurethane
    Number Of Parts: One Part
    Type: Adhesive
    Usage: Sealing
    4.8 14

    This stuff is awesome and Jamestown has the best price.....


    This stuff is awesome. If you roughen up the surface it will bond to almost anything. The only thing it is not recommended for is Masonary and Concrete. There are better products like NP1 by BASF. This stuff can be messy but you would expect that and acetone or lacquer thinner takes it off no problem. Any solvent thinner will actually clean it up but acetone or lacquer thinner are the best for cleaning the surface before application because they don't leave any residue. Don't buy more than you need of the 221 but if you have an old tube that the end hardens up on, just poke a hole below the cured area and squeeze it out. Tape over the hole and work your way down the tube. Store in a dry place as this stuff is moisture cured. Needs a couple of days at least before painting over to be safe. Moisture and temperature will determine this. I warm the tube up before using it either in the sun or with a heat gun and it really helps with the flow and application. Heck I use some of this to put part of woodstove door gasket back in place and it is still there. Totally violating what this product is made for. If you had to have one tube of sealant around, this would be the one. Always have a tube in my shop. You will not be disappointed with this product.

    Firewire300 aka VE3OPD

    EN58 near Duluth MN


    Good Goop


    Used it to put a back window into a convertible.Good, but messy, goop.

    Bill the Mechanic



    This product really shines


    We replaced a bulkhead that butted up against the side of the house. That edge had about a 1/4" crack that needed to be sealed. At first, we tried caulking the edge, but the caulk failed and leaked from the rain and the runoff from the roof. I searched around and found the Sikaflex product which is advertised as a marine sealant. So, I tried using the Sikaflex in place of the caulk. The product worked great. It can fill and seal a much larger crack than caulk can and it has proven to be totally waterproof. It also spreads uniformly and isn't unattractive.


    Boston, MA


    I have bought Sikaflex again and again


    This was for doing seam along gunwhale. Taped gunwhale and deck using 3M 2090 blue tape and then used a small teaspoon as tool, and gloved finger in tight areas. Used soapy water as tooling agent with great results. Did about 3 foot sections and moved steadily along. When satisfied, pulled up tape immediately. Used alcohol immediately to clean up any accidents. Looks great.




    Sika above and below


    Unlike 5200, hardware can be removed without damaging the points of adhesion. While it can be used underwater, it's best uses are for bedding pretty much anything on a boat. As it dries to a rubbery consistency you can even use it to mount pumps to flat dry surfaces, including bilge pumps and float switches. Excess can be left on to dry and then can be trimmed and peels off. It sands very well and can be color matched with your favorite paint.


    West Hartford, CT


    good stuff for elastic seals....


    Wish I'd purchased the white version, but this stuff works well as a long term sealant on any application that involves movement. I used it on my RV, and it holds up well against the weather as well as against the motion of a Motorhome in transit.

    healey driver

    Knoxville, TN


    excellent sealer-adhesive


    sealed slideout in RV


    Rockwood, TN


    Great product and great service


    Great waterproofing product. Excellent sales experience.

    D McC





    I actually used this product to seal the sewed seams on my wetsuit. It worked great. Used the left overs on some wooden framed windows on a 37 Elko, still water tight.


    Wilmington, NC


    Great stuff to seal horse trailer roof.


    Used it to seal the aluminum seals on the roof of a Sundowner Horse trailer. It worked great. Using a curved piece of metal to shape and grade the calk in places is a big help.


    Oxford, OH


    Sikaflex 221 One-Component Adhesive Sealant



    Related Items:
    TotalBoat Blogs Live Tech Support Jamestown Forum Free Catalog