gelcoat repair

I bought some gelcoat from the manufacturer of my kayak but it did not come with a catalyst. Does anyone know what the ratio of catalyst to gelcoat should be?

I use
three drops to one tablespoon of Gelcoat for my Wenonah repairs. Seems to work and hold up. I have never gotten the colour scheme perfect though. I guess 5 years of use naturally fades the Gelcoat.

The catalyst should have instructions
But here’s a link to a guide on the ratios required:

(around 10 to 15 drops per Oz.)

Add more catalyst in cooler weather. Use a well ventilated area. You can use something like a hair dryer to speed up the hardening (i.e. higher temperatures/more catalyst gives quicker hardening). Ensure it’s mixed thoroughly before using.

Polyester is not as critical as to the ratios as epoxy is.