Thorough mixing of catalyst into resins and gelcoat is very important. Addition of the correct amount ensures the best results. The table below gives the correct ratios of catalyst to resin and gelcoat by weight. 

1% is considered a slow mix, 2% is ideal, 3% is a fast mix. Additions outside these bands are not recommended for proper curing. The addition of more than 4% may result in a failure to cure. 

The pot life of these mixes is also determined by temperature. The higher the temperature the faster the cure. As a general guide 2% addition at 20ºC gives 15-20 minutes pot life. The resin cures quicker if left in a large quantity such as in the mixing bucket or in castings.