Danny Inc

Repair Leaks, Cracks, and Holes with Flex Seal

Cracks, holes, and leaks drive us crazy. That’s why we love products like Flex Seal. Flex Seal Liquid, Tape, and Clear Spray stops the leaks, fills in the cracks, and covers the holes in just about every surface you can imagine. You’ve probably seen it on TV.

Top SalesProduct LinkPrice
Great Stuff 99108824 Smart Dispenser Gaps & Cracks Creamfrom $6.26
Flex Seal Spray Rubber Sealant Coating 14-oz Clear (2 Pack)from $25.98
Flex Seal Spray Rubber Sealant Coating 14-oz Clearfrom $12.99
Flex Seal Spray Rubber Sealant Coating 14-oz White (2 Pack)from $25.98
Flex Seal Spray Rubber Sealant Coating 14-oz Blackfrom $12.99
Flex Seal Liquid Rubber in a Can 16-oz Clearfrom $14.99
Flex Seal Spray Rubber Sealant Coating 14-oz Black (2 Pack)from $25.98
Flex Seal Liquid Rubber in a Can 32-oz Blackfrom $29.99
Flex Seal Liquid Rubber in a Can 16-oz Whitefrom $14.99
Flex Seal Liquid Rubber in a Can 16-oz Blackfrom $14.99
Flex Seal Liquid Rubber in a Can 1-gal Whitefrom $89.99
Flex Seal Liquid Rubber in a Can 32-oz Grayfrom $29.99
Leak Stopper Rubber Flexx - Waterproof Repair & Sealant Spray - Point & Spray to Seal Cracks Holes Leaks Corrosion & More | White - 1 Bottle 15 Ouncesfrom $9.97

Does it work? Let’s find out! We’ll review Flex Seal’s rubber sealant, tape, and aerosol right here so you can choose the best one for the job you want to do.

#1 Flex Seal Liquid Jumbo 32 Ounce

What’s in this stuff? We don’t know. Flex Seal says their ingredients are a proprietary formula. Some people call it an elastomeric coating. We call it a miracle worker.

We’ll start by reviewing their Liquid. It has a fairly thick consistency and comes in a can. The one we chose is the Jumbo, or quart size, with 32 ounces. Flex Seal says this will cover about 40 square feet, depending on how many coats you use. It has a shelf life of 24 months so you don’t need to finish all your projects in a weekend.

Where and how can you apply Flex Seal Liquid?

You can brush, roll, spray, and pour Flex Seal Liquid onto concrete, brick, stone, stucco, asphalt, wood, tile, glass, metals like aluminum and copper, vinyl, fiberglass, porcelain, ceramics, and many kinds of plasticized surfaces including polyurethanes. You can also dip any of these kinds of things into Flex Seal to coat it.

What real world applications are there?

Just imagine all the many places and ways you can use Flex Seal around your home. Maybe you have leaks in the roof, a gutter, or a pipe. Perhaps your basement is too damp and you want to coat the walls. Those cracks in your driveway or sidewalk or patio, the problem area in the shower stall…you get the idea. Maybe you just want a nonslip rubber coating on something like your rain barrel or a tool.

Is Flex Seal safe?

Once it’s cured (after 48 hours), Flex Seal says their coating is safe for pets, plants, and people. You can even lay your sandwich down on it.

Can Flex Seal withstand harsh conditions?

Flex Seal says their Liquid (when cured) expands and contracts according to the weather. It can handle temperatures ranging from 0 to 250 degrees and doesn’t mind sunshine, water, rain, snow, or hail. It won’t mildew, fade, or turn yellow from UV rays.

Does Flex Seal actually work?

Here’s the big question—does it work? We say yes. Have a look at this video for yourself.

Where can’t I use Flex Seal?

The maximum amount of pressure Flex Seal can withstand is 150 psi, depending on the coats you’ve applied. They don’t recommend using it on any kind of bike, motorcycle, or car tire. It also doesn’t last long if it’s exposed to gasoline, but it is resistant to oils.

Even though it’s able to withstand oil, make sure the surface where you apply it is dry, clean, and oil-free.

Instructions for applying Flex Seal Liquid

It’s probably best if you wear some old clothes when you’re ready to apply Flex Seal. If you make a mess, you can clean it by wiping the excess with a dry cloth or paper towel, then with mineral spirits. Neither water nor alcohol will work to remove a spill.

While you work, especially if you’re using Flex Seal in hot and humid conditions, it’s a good idea to close or cover the can as much as possible because the Flex Seal Liquid will cure quickly in the heat. Once it forms a skin on the top, you need to remove that crusty part or it will make the rest of the coating lumpy inside the can.

Clean and dry the surface you want to patch or coat. Remove any oil or grease. Consider roughing up very slick surfaces with sandpaper, but remove the dust afterward.

Use a paintbrush or roller, a sprayer, a sponge, or simply pour the Flex Seal Liquid onto the surface. If you’re dipping an object into the can, swirl it slightly. Then let it drip off, then dry in the same vertical position.

Flex Seal takes about 6 to 12 hours to dry to touch, but 24 to 48 hours to cure completely. Leave the surface or object alone for this long before you test it. You can add additional coats if you desire.

If you want to seal up a leak underwater, check out the Flex Tape review below.

#2 Flex Tape Black 4″ x 5′

Flex Seal Flex Tape is like duct tape, only better. You can’t stick duct tape to a wet surface because it won’t adhere. But Flex Tape will stick to almost anything, even underwater. You can seal up a leaky pipe or garden hose and save your aquarium fish with a quick patch, no sweat. It’s perfect for emergency repairs.

Instructions for applying Flex Tape

When you’re ready to apply Flex Tape, cut it down to size first. Then peel off the backing and press it onto the place you’re fixing. Mash down any air bubbles. Once you’ve affixed it, it can’t be moved so aim well the first time.

Flex Tape will stick as long as the temperatures ranges from 20 to 120 degrees F. Although it can resist temperatures up to 200 degrees F, anything over that will make its adhesive turn to goo and it won’t hold.

Where can you apply Flex Tape? And where won’t it stick?

Use this tape to seal up most plastics, vinyl, glass, rubber, fiberglass, Formica, metals, wood, ceramic, porcelain, tile, acrylic, stone, dry wall, and stucco.

Flex Tape won’t stick well to some porous surfaces and fabrics, waterproof/water repellent substrates, greasy, oily, or silicon-treated materials, and some plastics.

It’s not a good idea to patch a tire or fix a radiator hose with Flex Tape. It won’t do well with gasoline or oil and it’s not safe for direct contact with drinking water.

If you want to paint the tape after you’re done, use the Flex Seal aerosol we review below.

#3 Flex Seal Clear Set of 2 Cans, 14 OZ

If you don’t need a quick patch with tape and you want a lighter-weight sealant coat than the Flex Seal Liquid can give you, you need the Flex Seal Clear aerosol. It’s like spray paint in a can and comes in several different colors including clear.

The Clear can adhere to any surface that the other Flex Seal products can so it’s great in the bathroom, the garage, and more. You can even spray it onto a wet substrate although it will take longer to dry and cure.

How to use Flex Seal Clear

It’s best if you work in temperatures over 60 degrees F. Stay away from open flames and sparks, and make sure your space is well-ventilated.

To apply Flex Seal Clear, hold the can about a foot from the surface you want to cover. Shake the can well. Spray a light coat over a slightly larger area than just the crack or leak you want to seal.

Continue to apply coats until you’re satisfied with results. The sealant dries to the touch within 2 to 3 hours, then cures completely in 24 hours. One can can cover up to 12 square feet.

It’s a good idea to invert the can and do a short burst to clear the nozzle after use.


Flex Seal is a very handy gadget to have when you want to seal a leak or close up a crack in a pipe, a window, a wall, a pool, a tub, and so much more. When the Liquid, Tape, and aerosol are applied according to the directions, they form a durable, resistant coating perfect for saving the day.

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