209 Extra Slow Hardener® is formulated for use with WEST SYSTEM® 105 Epoxy Resin® or general coating and bonding applications in extremely warm and/or humid conditions or when extended working time is desired at room temperature. Provides approximately twice the working time of 206 Slow Hardener®. 105/209 forms a high-strength, moisture-resistant solid with excellent bonding and coating properties. The mix ratio is 3 parts resin to 1 part hardener by volume. Not intended for clear coating.
Controlling exotherm (the heat released by the chemical reaction between resin and hardener that cures epoxy) is very important, especially when mixing larger batches of resin and hardener. If not controlled, epoxy’s exothermic reaction can be dangerous.
During warm summer months, WEST SYSTEM Epoxy working time and other handling characteristics will be different than at other times of the year. Our cure times are based on an ambient temperature of 72°F, but in warmer temperatures, the epoxy will cure faster. There are some steps you can take to extend epoxy working times and ensure good results when using WEST SYSTEM Epoxy in warm environments.