Gelcoat repair above the waterline

Gelcoat repair for your boat

Do you have damage to the gelcoat of your boat and do you want to repair it? No problem, then you have come to the right place at Polyestershoppen. We sell everything for your boat. From epoxy to polyester. Minor or major damage to your boat's gelcoat occurs regularly. Did you know that you can easily repair minor gelcoat damage such as scratches and dents yourself? In this information article, we explain step by step how to do a gelcoat repair yourself. That way, your boat will look pristine again for the new sailing season!

Do you have any questions about gelcoat repair? Feel free to contact our product experts. We are happy to advise you!

Gelcoat repair manual

Gelcoat is the protective layer on the exterior of many boats made of composite materials. If a boat's gelcoat is damaged, it can be repaired by applying a piece of gelcoat to the damaged area and sanding it until it is smooth.

There are different types of tools that may be needed for the repair, depending on the size and location of the damage. Sometimes it is necessary to apply a small amount of gelcoat with a spray gun, while other repairs can be done with a simple disposable brush It is important to use the right procedure and techniques when repairing gelcoat, as an incorrect repair can lead to further damage or irregularities in the boat's appearance.

Below you can read all the information on how to repair your boat's gelcoat.


Make sure you have enough materials on hand to do the gelcoat repair properly. Did you order too many materials? No problem, you can return unopened packages free of charge. For a gelcoat repair you will need the following products:

Tip:  with the gelcoat repair set, you immediately have all the materials you need to get started with a small gelcoat damage.

Step 1. Sand the surface

Roughly sand the surface with P80 grit paper. Continue sanding until the damage is gone and sand the surface around the damage with P1200-grit paper. After sanding, carefully degrease the surface with acetone.

Step 2. Prepare polyester topcoat

For gelcoat repair above the waterline, you can use Polyester topcoat (minor damage) or Gelcoat putty (major damage).

Polyester topcoat Gelcoat putty
Max. 1 mm thick Max. 5 mm thick
Available in all RAL colours Transparent

In this article, we use Polyester topcoat to repair the damage. Prepare the gelcoat in the following way:

  • Stir the gelcoat gently. 
  • Add approx. 2% MEKP hardener
  • Mix well again with a mixing spatula.

Step 3. Apply the topcoat

Apply approx. 1 mm of polyester topcoat to the area of the damage. Do you want to apply another layer on top? Then let the first layer cure first. 

Allow the topcoat to cure for at least 48 hours before proceeding with the final step.

Step 4. Finishing

Is the topcoat fully cured? Then you can finally finish by sanding and polishing the surface. Sand the repair area completely flat with 400 grit. Then sand the surface with grit 600, 800, 1200, 1500 and finally with grit 2000.

Then polish the surface using the manual polishing kit or a polishing machine with matching polishing pads.

More information about boat gelcoat repair?

Do you have any questions about gelcoat repair above the waterline? Feel free to contact one of our specialists. We are happy to advise you to make your project a success. Send us a WhatsApp message, email or call +31 85 022 0090 for free and non-binding advice.

Do you still have questions about gelcoat repair above the waterline? Feel free to contact one of our specialists. We will be happy to help you make your project a success. Send us a WhatsApp message, email or call +31 85 022 0090 for free, no-obligation advice.

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Do you have a question?

Do you have a specific question? Call one of our specialists for free advice +3185 0220090