Flex Seal Dry Time (& Speeding Up Tips)

Flex seal fixes holes, cracks, and water leaks. However, the Flex seal must dry (and cure) before it can protect surfaces. So, how long does Flex seal take to dry?

Flex seal takes 2-3 hours to dry to touch and 24-48 to cure. However, the dry time of the Flex seal depends on the room temperature, humidity levels, and thickness of the coat.

There are a few methods that you can use to speed up the dry time of the Flex seal. Check them out. 

Flex Seal Dry Time Between Coats

Flex seal must dry for 24 hours before re-coating. Press the finish to know if the Flex seal is dry enough for a re-coat. If the Flex seal finish feels moist or soft, it hasn’t dried yet. If the finish is hard and dry, you can re-coat it.

For the flex seal to dry, its solvent must evaporate. The evaporation process of the flex seal depends on the humidity levels and room temperature. The lower the humidity, the faster the flex seal dries.

If you re-coat too soon, the Flex seal finish will turn sticky. That’s because the solvent will be trapped between two coats of Flex seal and won’t evaporate fully. Since the solvent didn’t evaporate, the old Flex seal coating will still be wet, so the new coating won’t stick. 

Flex seal is made by combining rubber and solvent. Once the sealer is applied, it seeps into the cracks and holes of the seal to seal it. The solvent turns the Flex seal into a liquid form and dissolves it so it can seep through the tiniest cracks and repair them. 

Flex Seal Cure Time

It takes flex seal 24-48 hours to cure. For Flex seal to cure, the solvent must evaporate and the coating must harden and compact. The curing process occurs through the solidification of the rubber paste. Once the flex seal has cured, it becomes waterproof and strong enough to support daily weight and use. 

There’s a difference between the drying and curing time of Flex seal. To dry, the Flex seal solvent must dry. However, the rubber paste must solidify, and the coating must harden and compact for the Flex seal to cure. The solidification of the rubber paste and the hard (& compact) coating helps the Flex seal to cover cracks and leaks.

However, the size of the crack and the thickness of the Flex seal coating determine the cure time. For instance, larger cracks require more Flex seal paste, which will take longer to cure. Conversely, smaller holes don’t require much Flex seal, meaning the sealer dries (and cures) faster.

The longer the Flex seal takes to dry and cure, the stronger it becomes.

Also, the Flex seal must cure before exposing it to water. On average, it takes 24-48 hours for Flex seal to dry enough to handle exposure to moisture. If the Flex seal is to be used outdoors, manufacturers recommend its application 24 – 48 hours before the rain starts.

If You Re-coat Flex Seal Too Soon:

If you re-coat the Flex seal too soon, the sealer will take longer to dry. This is because the existing coats don’t have enough time to dry and solidify, creating a moist and weak base for successive coats.

When you apply the next coat over the moist base, you slow down the evaporation and drying process of each coat, causing the Flex seal to take several hours to dry.

Re-coating the Flex seal too soon can also cause variations and patches in the finish. This is because the Flex seal coats will not dry evenly, causing some parts to appear darker or lighter than others.

Re-coating too soon can cause the Flex seal coating to turn sticky or tacky. While a tacky Flex seal can be fixed, there are cases where it can’t, and you must remove and re-apply it.

How To Speed Up Flex Seal Drying Time?

Since the Flex seal dries through evaporation, increasing the evaporation rate will speed up the dry time of the Flex seal. To increase the evaporation rate, increase the air circulation and the heat around the Flex seal coating. 

1. Use a Hairdryer

Use a Hairdryer

A hairdryer will increase the heat around the Flex seal coating; this also increases the evaporation rate.

Here’s how to do it: 

  1. Use the medium settings of the Hairdryer. 
  2. Set the nozzle of the hairdryer 2-inches away from the Flex seal coating. 
  3. Move the hairdryer around the Flex seal coating for 5 minutes. 
  4. Wait 10 minutes. 
  5. Use the hairdryer again over the Flex seal coating for 5 minutes. 
  6. Leave the Flex seal to dry naturally for 6-10 hours. 

Tip: You shouldn’t fully dry the Flex seal coating using a hairdryer. That’s because the coating won’t harden or compact naturally, so the finish will be weak.

2. Apply The Flex Seal Outdoors

The higher the air circulation around the Flex seal coating, the faster it dries. So, applying Flex seal outdoors means that the coating will dry faster. 

However, the Flex seal coating shouldn’t be exposed to rain as it can ruin the finish. 

3. Use a Dehumidifier

Use a Dehumidifier

You can make your Flex seal dry faster by reducing indoor humidity. Humidity refers to the atmosphere’s moisture content (or water vapor).

The higher the humidity level, the slower your Flex seal will dry. But if you reduce the humidity levels, the Flex seal will dry faster. The ideal humidity level to allow the Flex seal dry is between 30% and 50%.

To reduce the humidity levels, use a dehumidifier.  Follow the manufacturer’s guide to learn how to use the dehumidifier. For best results, run the dehumidifier for 24 hours after application.

Tip: To make Flex seal cure faster, you need to increase the airflow around the Flex seal coat. You can do this by ensuring proper room ventilation.

Final Words

Flex seal takes 2-3 hours to dry to touch, 24 hours to dry enough for a re-coat, and 48 hours to cure. However, the drying and curing time of the Flex seal depends on the humidity levels, thickness of the coat, and the number of coats.

To speed up the dry time of Flex seal, use a hairdryer, dehumidifier, or apply the sealer outdoors. 

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