Whether it’s your house, car, or RV, leaks are the last thing you want to overlook. They can cause some serious damage if not dealt with quickly and efficiently.
Luckily, there are plenty of options for sealant on the market, the two most popular ones being Rust-Oleum Leak Seal and Flex Seal. Both solutions are pretty similar, and this often confuses people when trying to choose a reliable sealant to get rid of cracks, gaps, and holes.
In this Rust-Oleum Leak Seal vs Flex Seal guide, we’re comparing the two products to help you decide which one is right for your needs.
1. Available Formulations
Both manufacturers offer a range of sealing product formulas including sealing tapes and glues. Today, however, we’ll be focusing on their liquid can and spray rubber sealants.
For Rust-Oleum, there’s the regular Leak Seal, which is a spray sealant, and the Leak Seal Brush, which is a liquid sealant. On the other hand, Flex Seal offers Flex Seal Liquid and Flex Seal Spray.
2. Sizes and Pricing
As anyone would expect, the bigger the size of the sealant container, the longer its service period. This is an important aspect to consider when trying to decide between the different sizes of the two products.
For Rust-Oleum Leak Seal, the following size options are available:
- Rust-Oleum Leak Seal Spray: 11 oz and 12 oz.
- Rust-Oleum Leak Seal Brush: 8 oz and 30 oz.
As for Flex Seal, it offers the following size options:
- Flex Seal Spray: 14 oz and 17 oz.
- Flex Seal Liquid: 16 oz, 32 oz, 1 gallon, and 2.5 gallons.
Regardless of the brand, all of the size options are priced more or less the same.
3. Available Colors
The color of the sealant can make all the difference in the final look of the treated surface. If you don’t have the time or the desire to paint over the sealant after you apply, or if the sealant you’re using isn’t designed to be coated in paint, this feature will come in handy.
With Rust-Oleum Leak Seal, you can take your pick from the following colors:
- Rust-Oleum Leak Seal Spray — 11oz: clear, 12oz: black, aluminum, white, brown.
- Rust-Oleum Leak Seal Brush: black and clear for both size options.
With Flex Seal, you can choose from the following colors:
- Flex Seal Spray — black, white, and clear.
- Flex Seal Liquid — black, white, gray, and clear.
4. Material Compatibility
You can use both Rust-Oleum Leak Seal and Flex Seal on a wide variety of materials including:
- Wood
- Glass
- Metal
- Concrete
- Masonry
- Cement
- Some types of plastic, vinyl, and rubber
- Caulk as long as it’s not silicone
As you can tell, none of the two sealants has a clear advantage over the other when it comes to material compatibility.
5. Application
Even in the application department, there are no major differences to consider in the Rust-Oleum Leak Seal vs Flex Seal comparison. The process is pretty similar for both products and goes along the lines of the steps below:
- Thoroughly clean and dry the surface before applying the sealant. Both manufacturers also recommend that the surface is smoothed down with sandpaper or wire brush to promote adhesion.
- With spray cans — shake the can well then spray at a distance of 8 – 12 inches from the surface to be treated.
- With brush sealants — you can brush, dip, roll, or pour the sealant onto the surface to be treated.
- Generally, it’s recommended to apply multiple coats for the best results. Make sure that each coat is applied only after the previous one has dried fully.
6. Durability
There are several points to keep in mind when comparing the durability of sealants:
- Temperature resistance — Flex Seal is less resistant to temperatures, although it’s designed to endure temperatures ranging between -80 to 350 degrees Fahrenheit. So, it may be less suited for outdoor use.
On the other hand, Leak Seal seems to perform more efficiently in winter cold and summer heat. It’s also not meant to withstand extreme temperatures, but it tends to hold together better than Leak Seal.
- Pressure resistance — both Leak Seal and Flex Seal will handle normal hydrostatic pressure, but it is not extreme pressure.
- Water-resistance — both sealants can well endure moisture and rain, but not continuous submersion in water.
7. Curing
For the Rust-Oleum Leak Seal, the spray and liquid sealant dries to the touch and can be recoated within 20 to 30 minutes. Curing usually completes within about 24 hours for both formulas.
As for the Flex Seal, the liquid formula fully dries within 24 to 48 hours and completely cures within 48 hours. On the other hand, the spray formula dries and cures usually within 24 to 48 hours.
While it may seem that the Leak Seal has the upper hand in this department, keep in mind that the curing time depends mainly on air temperature, humidity, and thickness of the coating. It also varies according to the way the manufacturer measured it.
8. Painting over
Painting over the sealant can be an important factor to consider, especially in projects where appearance matters.
On one hand, Flex Seal isn’t designed to be coated in paint. This goes for both formulas.
On the other hand, Leak Seal products can be painted over without issues.
9. Food Safety
Finally, if you’re wondering whether or not you can use the sealants on water or food containers, the answer is no.
Both the Rust-Oleum Leak Seal and the Flex Seal are not food safe, so you should not use them for sealing containers that anyone will drink or eat out of.
Rust-Oleum Leak Seal vs Flex Seal — Which One Should You Choose?
Whatever you end up choosing, you can’t really go wrong. Both sealants are quick and effective.
That being said, if you’re looking for something with a bit more flexibility, go with Flex Seal. But if you want a sealant that’s better suited for outdoor use in harsh weather conditions, the Leak Seal is up for the job.