Flex Seal and Flex Seal MAX feature the exact same trusted rubberized liquid formula. The only difference is the size and coverage. MAX sizes are "giant-sized" cans meant for contractors and DIYers tackling larger projects, offering up to 20% more product and coverage than the standard aerosol can.
Customers say that Flex Seal is a versatile and easy-to-use product that effectively seals leaks and cracks in various applications, including roofs, gutters, and plumbing.
Do not use Flex Seal on high-pressure or high-heat items (engines, radiators), gas tanks, potable water containers, or for long-term repairs on vinyl, PVC, or foam. It is not food-safe, and it does not bond well to greasy, oily, dirty, or certain nonporous surfaces like silicone, polypropylene, or polyethylene plastics.
Depending on the specific type of repair you are tackling, several alternatives outperform Flex Seal. For heavy-duty sealing, Gorilla Waterproof Patch & Seal is widely preferred for its stronger adhesion and UV resistance. For structural waterproofing, specialized mastics like Sika Sikaflex (polyurethane) or Henry 208R (roofing wet patch) offer superior, permanent bonding.
Flex Seal MAX, 17 oz, 2-Pack, Clear, Stop Leaks Instantly, Waterproof Rubber Spray On Sealant Coating, Perfect for Gutters, Wood, RV, Campers, Roof Repair, Skylights, Windows, and More.
When choosing between Flex Glue and Gorilla Glue, you need to match the adhesive to your specific repair. Flex Glue is a thick, rubberized paste best for waterproof seals and flexible bonds. Gorilla Glue refers to a line of adhesives, but its flagship product is an expanding, rigid polyurethane glue famous for heavy-duty woodworking and outdoor projects.
Flex Seal usually becomes dry to the touch within 2-3 hours and fully cured within 24-48 hours. If your Flex Seal still feels sticky or tacky after application, it may not be fully cured. Please note that dry times can vary due to temperature, humidity, and thickness of the coat.
Flex Seal can last anywhere from a few months to several years. Its exact lifespan depends heavily on the severity of the environment, surface preparation, and whether it is used as a short-term patch or a long-term protective coating.
Epoxy putty: Epoxy putty is a two-part compound that can be mixed together to form a strong adhesive. It's ideal for sealing leaks in pipes and can be used on both metal and plastic pipes. Epoxy putty is also resistant to chemicals and can be used on surfaces that come into contact with water.
WD40 can be used to aid in the removal of Flex Tape. But the most effective way to remove Flex Tape from surfaces is Flex Adhesive Remover. It's designed for the job.
Sealers and compounds are essential plumbing consumables designed to ensure leak-proof connections and long-lasting performance in both domestic and commercial settings.
If Flex Seal gets wet before it fully cures (which takes 24 to 48 hours), it can compromise the seal. Uncured exposure to water often causes bubbling, sagging, poor adhesion, and flaking. However, the exact consequence depends heavily on the specific product being used:
Flex Seal Spray is an aerosol liquid rubber designed for broad coverage, small cracks, and hard-to-reach areas. Flex Seal Liquid is a thick rubberized coating intended to be brushed, rolled, or poured, making it ideal for filling larger holes, gaps, and covering heavy-duty surfaces like roofs or foundations.
Flex Seal Spray can be used for minor plumbing repairs, such as temporary leaks of PVC pipes, joints, or connections. However, it's not a permanent fix for pressurized water systems. Flex Tape or Flex Glue may be better choices for plumbing depending on the type of repair you need.
When layering our products, it's best to put Flex Seal Liquid on top of Flex Seal Liquid or Flex Seal spray on top of Flex Seal spray. You may have used our products together; however, we always recommend testing first, as different surfaces may have different results.
Flex Seal will not stick to nonporous materials, water-repellent surfaces, and any material that is dirty, greasy, or oily. Specific materials it struggles to bond with include silicone, polypropylene (PP) and polyethylene (PE) plastics, foam, and certain types of heavily plasticized vinyl or rubber.
Apply 2 to 3 coats of Flex Seal for most standard repairs. However, the exact number depends on your project:
Yes you can! It's most effective at removing the residue left behind from peeling Plasti Dip off. However, if left to sit on rubber, it can break the rubber down.
Flex Seal is generally non-toxic and inert once fully cured, but it is not food-grade and should never come into contact with drinking water or be ingested. The curing process takes 24 to 48 hours, during which it releases potentially harmful fumes.
There is no single "strongest glue" in the world. The ideal adhesive depends entirely on the materials being joined and the conditions your project must endure.
Krazy Glue is different—it's made from cyanoacrylate, a fast-acting, colorless adhesive that's incredibly strong and quick to trust. Once cured, it can hold over 1,000 pounds per square inch.
J-B Weld is stronger than Gorilla Glue for heavy-duty, rigid repairs like metal, concrete, and engine parts. Gorilla Glue is excellent for woodworking and porous materials, but it expands as it cures and creates a slightly more flexible bond.