What Happens If Flex Seal Gets Wet Before It Cures

What Happens If Flex Seal Gets Wet Before It Cures

Flex seal is an awesome rubbery spray that you use to fix cracks and holes. You spray it on, let it dry and it stops leaks. But if you get the flex seal wet too early, it causes big problems! Keep reading to understand What happens if flex seal gets wet before it cures.

Understanding Flex Seal And How It Works

Flex seal comes in a thick liquid in a can. The liquid is special – it has polymers in it which are sticky molecule chains. It also has solvents which are chemicals that easily turn to gas.

To use flex seal, you spray or brush the thick liquid onto surfaces like metal, wood, concrete and more. Say you have a crack on a pipe or wall, you coat that crack with the liquid.

Here’s the cool part – when you spray out the liquid, the solvents start turning into vapor and the polymers are left behind. The polymers then bind together and turn the liquid into a solid, flexible, strong coating. It’s like a rubber layer that sticks to the surface.

This transformation from liquid to solid rubber takes time after you apply it – could be a few hours to a day. This time allows the reaction to completely finish.
The final rubber coating stretches but doesn’t break. So even if the crack moves, the seal can flex along but still covers the gap, stopping any leaks!

Problems With Getting Flex Seal Wet Too Soon

If you get flex seal wet before adequate curing, you interrupt the process in the following ways:

Here Are The Points With 2 Additional Lines Each In Straightforward Language:

1. Solvents do not evaporate fully

Evaporation of solvents is important for the polymers to bond together tightly. When the flex seal is wet early on, the evaporation slows down. This leaves excess solvents behind in the coating.

As a result of the slowed evaporation, the solvents stay trapped in the coating. They take up space between the polymers, limiting bonding.

2. Polymers do not link properly

Since all the solvents are still present, the polymers do not get a chance to properly crosslink and create a tight structure. The coating remains loose and gel-like. Without the polymers linking up as intended, there are gaps remaining in the coating. It does not solidify correctly.

3. The seal becomes weaker and less effective

Due to the above issues, the conversion to a robust solid seal does not occur correctly. Trouble areas that were meant to be sealed become weaker and prone to leaks. The flex seal layer stays soft and mushy. The end result is easy leaking through the soft coating. It fails to properly seal and protect areas as designed.

4. Bonding to the surface is reduced

Normally flex seal bonds tightly to the applied surface as it cures. When wet early, the chemical bonding process gets interrupted. This leaves a weak physical bond prone to detachment. The end result is a flex seal that easily peels away from the areas it was meant to stick to.

5. Risk of bubbles forming

Getting flex seals wet can result in solvents and moisture getting trapped within the coating as it tries to cure. This leads to bubble formation over time. The bubbles create weak spots in the seal that compromise the protective barrier.

6. Promotes early wear and tear

Wetting the flex seal too early essentially freezes it in an uncured state. This makes the coating much more prone to damage from abrasion or impacts. Long term durability is reduced as the seal wears down faster than intended.

Effects On Bonding Ability And Strength

Apart from the chemical transformation, getting flex seal wet early on also affects its key practical properties:

Here are the points expanded with 2 additional sentences each using easy to read language:

1. Poor surface bonding

Flex seal requires good contact and grip with the target surface to bind well. Exposure to excess moisture prevents this mechanical attachment. This makes it easy for the layer to peel away later on. It also causes leaks through any gaps between the flex seal and the surface.

2. Diminished flexibility

The rubbery nature gives flex seals the ability to stretch and flex with surfaces. But wet exposure makes the coating stay tacky and gel-like rather than stretchy. This causes it to crack or break rather than bending as surfaces move. It also cannot expand and contract smoothly with temperature changes.

3. Lower durability

Due to poor bonding and flexibility, the wet seal coat will deteriorate faster when exposed to elements or mechanical forces. The lifespan of the seal reduces significantly. This means the seal may fail too soon to adequately protect surfaces. It also cannot stand up to wear and tear and needs replacement sooner.

4. Weakens over time

If the flex seal gets wet too early, the polymers do not fully set and bind together. This causes the sealant to get more brittle and porous over time. Exposure to sun, weather, and stress then degrades the layer faster than normal.

5. Uneven finish

Wet application causes uneven absorption and drying in the flex seal material. This leads to irregular textures, bumps, divots, or weak spots across the finish. An uneven surface makes consistent sealing difficult and looks unprofessional.

How Long To Let Flex Seal Cure Properly

So how long should you let flex seal cure before allowing water exposure? The ideal curing timeline is:

– Tack-free dry state: 2 hours

The surface should not feel sticky to touch after air drying flex seal for 2 hours. It forms a solid outer film yet still wet underneath. Do not allow water exposure at this stage yet.

– Full drying time – 24 hours

Letting the flex seal sit for a full day allows all solvents to evaporate and the coating to fully harden. It can now resist light moisture but may still soften or swell if soaked.

– Optimal performance after 7 days

After a week of curing, the flex seal reaches maximum strength, flexibility and waterproofing ability. The polymers and ingredients bind together into a durable, rubbery barrier. Only at this point should you test full water exposure.

– Gets more durable over more time

While 7 days is optimal, flex seal continues to cure and fortify further over several weeks. More extensive cross-linking over months produces extremely resilient, long-lasting protection.

– Test on small spots first

Before exposing full sections, test how cured the flex seal is by allowing water on small areas. Check if any swelling or washing off occurs to confirm it is ready for total submersion or wet conditions. Correcting issues from wet exposure

What To Do If A Flex Seal Was Accidentally Exposed To Moisture Too Early?

1. Dry out the area completely

Use towels, heat guns etc. Ensure no moisture or dampness remains on the seal or affected surfaces. Allow 1-2 days of warm dry conditions for thorough drying. Check with a moisture meter if unsure. Extended drying prevents trapped moisture problems later.

2. Apply fresh thin layers of flex seal

Brush on 1-2 thin new coats of flex seal liquid after thorough drying. Allow proper curing times of 24 hours minimum between coats. More layers increase waterproofing ability. Letting each layer cure stops soft layers stacking together.

3. Check for leak proofing

Inspect the area under operation conditions, look for leaks near trouble spots. Run water over the area for several minutes. Mark any drips, moisture visible, indicating breach points. The fresh layers may provide adequate sealing if no leaks show.

4. Consider removal and re-application

If leaks persist in the problem area, it may be best to mechanically remove the weakened layer with scrapers. Then thoroughly clean and dry the surface before re-applying flex seal correctly from scratch.

Follow all directions about drying time between adding new liquid layers. Test again for water breaches after proper application and cure times.


The bottom line is that allowing flex seal to cure fully is vital for an effective, robust seal. Premature water exposure affects the solvent evaporation and polymer bonding process – compromising strength and leak protection.

Make sure to let it dry tack-free for 2 hours and fully cure for 24 hours before allowing contact with liquids. This gives the best long term performance.

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