Factors Affecting The Gel Coat Repair

Gelcoat is a resin system that is filled with colourant and thickening agents and applied to cosmetics and weathering coating of a composite part. Gelcoat is typically the first layer of a part to be applied. Correct application of gel coat is critical to get the optimum performance from it.

Many companies such as Anz Yacht provide Gelcoat repair that is based on thermoset resin that requires an initiator and proper temperature to cure thoroughly.  An incomplete cure will result in poor durability of the gel coat. This is often witnessed as premature fading, dulling of the gel coat surface or chalking. There are three variables that affect proper cure: Temperature, Film Thickness and Initiator level.

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In this article, we will discuss factors affecting the gel coat application in great detail.


  • Temperature


The temperature should be between 60-80° F with an optimum range being between 70-75°F. It is good to use an infrared thermometer to check the temperature of the mould surface and gel coat. Keep in mind that moulds stored in areas that are not climate controlled may not reach room temperature for quite some time.

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  • Film Thickness


The standard gel coat repair kit is designed to cure in films as thin as 12 mild(0.012 inches). However, it is recommended to apply them in coats of 18-20 mils to get the best cure, hide and print block. As the gel coat cures, it develops heat that helps it complete the cure cycle. If your coating is too thin and the temperature and the temperature is too low, it will not cure properly. Gelcoat can be applied on coats up to 24 mils.

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  • Initiator level


Gel coat should be initialized to set up to the point that you can touch it with the glove and not have it come up on your finger in 45-60 minutes from application. Generally speaking and depending on the temperature, a catalyst ratio between 1.2% to 3% will give you the proper cure rate.
We hope, we will give you enough idea on gel coat repair. Then what are you waiting for? Grab a boat painting company and put a gel coat in your boat as soon as possible. Check out here if you consider restoring the gel coat of your boat.