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  • Writer's picturePlasTech Services Inc.

What is the Best Way to Repair a Fiberglass Tank?

Updated: Dec 20, 2022

Fiberglass Tank Repair

Fiberglass tanks are used in various applications, from water to septic or chemical holding tanks. They are durable and reliable, but they can become damaged over time. When this happens, finding the best way to repair the tank to prevent further damage and maintain its integrity is essential. This article will discuss the best methods for repairing a fiberglass tank, including the tools and materials needed.

Tools and Materials Required for Fiberglass Tank Repair

The tools and materials needed to repair a fiberglass tank will depend on the tank's size and the damage's extent. Generally, you will need a sanding block, sandpaper, fiberglass resin and matting, solvent cleaner, mixing cups and sticks, and paint or gel coat. You may also need an electric drill with various bits for making holes for patching or reinforcing. You'll also want to consider protective gear due to the chemicals and safety gear if you need scaffolding.

CAUTION: The Chemicals used in making a fiberglass tank repair are toxic and flammable. Professionals should only handle them.

Preparing for Fiberglass Tank Repair

Before beginning any repairs on a fiberglass tank, it is crucial to properly prepare the surface area. This includes cleaning off loose debris or dirt. Then use a sanding block or sander to smooth down any rough spots. Make sure to wear safety goggles and a dust mask while sanding. Once the surface is clean and smooth, it's ready for patching or reinforcing.

Patching Fiberglass Tank Repairs

You can use patching materials such as fiberglass resin and matting for smaller holes or cracks in a fiberglass tank. Measure out an appropriately sized piece of matting and cut it to fit the hole area. Then mix up some of the resin according to the instructions on the packaging. Apply a thin layer of resin over the hole area, then lay down the matting on top of it. Cover with another thin layer of resin, then allow it to dry completely before sanding smooth.

Reinforcing Fiberglass Tank Repairs

For more extensive repairs on fiberglass tanks, you may need to use reinforcing materials. You'll also want to finish your fiberglass repair with a wax coating or a Gelcoat. Measure out appropriately sized materials for reinforcing each side of the damaged area. Once dry, you can sand down any excess material before applying paint or gel coat as needed.


Repairing a fiberglass tank requires careful preparation and planning to achieve optimal results. With proper tools and materials, you can successfully patch or reinforce any damage that has occurred on your tank's surface area. By following these steps, you can ensure that your tank will remain in good condition for years to come!

Need help?

We've repaired and relined hundreds of Fiberglass Tanks for some of the nation's largest chemical and pulp and paper processing companies.

Check out our FRP services page by clicking here, call us at 1-410-737-4700 or request a free repair quote at

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