How To Use Flex Paste

Flex Paste is a super thick rubberized paste that clings to the surface and instantly fills large gaps, cracks and holes. Once dry, Flex Paste turns into a strong, flexible, watertight, rubberized coating that seals out air, water and moisture on a variety of surfaces and objects. This article will show you everything you need to know on how to use Flex Paste.

New Stay Fresh Flex Paste Container


Getting ready to use Flex Paste.

How to properly apply Flex Paste.

Using on wet surfaces or underwater.

How long does it take to dry?

Helpful hints and tips.

How to clean up Flex Paste.

Storing and reusing.

Get Flex Paste.

Getting Ready To Use Flex Paste

Getting ready to use Flex Paste

Materials Needed:

• Protective gloves, clothing and eyewear
• Cloth/rag or Paper towels
• Painter's tape
• Plastic covering or tarp
• Flathead screwdriver
• Putty knife

IMPORTANT:  Before using Flex Paste, read all directions carefully and take proper safety precautions, such as being in a well-ventilated area and wearing protective gloves, clothing and eyewear. 

Prepare de Area


Start by cleaning your work surface so it is free of grease, oil and dirt.

Next, protect areas that you don’t want Flex Paste on. You can use painter’s tape to ensure clean lines and a drop cloth or plastic to protect other surfaces. 

To get the most out of your Flex Paste, make sure you READ THE DIRECTIONS CAREFULLY. Then follow along with the blog for a comprehensive step by step guide.

It’s a good idea to wear protective gloves, clothing, and eye wear. Clean off your work surface. It needs to be free of grease, oil and dirt.

Protect areas that you don’t want Flex Paste to ensure clean lines. You can use painter’s tape and a drop cloth or plastic to protect other surfaces.

How Do I Apply Flex Paste?

If you’re using a 1lb, 3lb or 12lb “Stay-Fresh” container of Flex Paste, take a flathead screwdriver and remove the lid. There is no need to shake or stir, as Flex Paste is ready to go. Grab a putty knife, trowel or similar tool, and remove an even layer of material off the top of the surface.

Flexpert Tip: Don’t scoop too deep! Doing so can cause air pockets to form, which may dry out your Flex Paste. 

Apply a generous amount of paste to the surface using smooth, even motions. It’s important to always allow each coat to dry before applying additional coats.

Applying Flex Paste in a Cartridge

Flex Paste cartridges are designed for use in a caulk gun. Before loading into the caulk gun, follow the steps below.

  1. Unscrew the cartridge tip.
  2. Remove the nub with a sharp knife but try not to cut any of the screw threads.
  3. Cut the cartridge tip in the center or to your desired thickness.
  4. Screw on the cartridge tip and you’re ready to go!

Can I Apply Flex Paste on Wet Surfaces or Underwater?

Yes, Flex Paste will work underwater and on wet surfaces. For best results, you may want to do some etching to increase adhesion. Also, you may need to apply a little extra Flex Paste when working underwater. 

How Long Does it Take for Flex Paste to Dry?

Once Flex Paste is exposed to air, moisture or humidity it begins to cure, forming a skin within 15 to 30 minutes. Flex Paste FULLY cures within 24-48 hours.

Always allow each coat to dry before applying additional coats.

Flex Paste Helpful Hints

Spackle and joint compound require sanding; with Flex Paste, light sanding is possible but not recommended. Just smooth it to your desired finish or add your own artistic texture.

  • Don’t wipe any excess Flex Paste on the inside of your container, as that could lead to drying.
  • Don’t mix dried product with fresh product during application
  • Before your next use, remember to remove any Flex Paste that may have dried, or skinned inside of the container.

How Do I Clean up Flex Paste?


When cleaning up uncured Flex Paste, don’t use water, Instead, use a clean cloth or a paper towel.

Mineral spirits and acetone will help speed up the process of cleaning up your area and tools.

How Do I Store Flex Paste?

How to store Flex Paste

When it's time to store your Flex Paste, just tap the lid back into place. To increase the life of your Flex Paste, store it in an air-conditioned, humidity-controlled environment.

And there you have it. Now you’re ready to use Flex Paste safely and properly for all sorts of DIY projects and repairs. For additional questions or concerns, please visit our FAQ page or contact customer service at 833-411-3539.


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