209 Extra Slow Hardener is formulated for use with WEST SYSTEM 105 Resin for 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. Forms a clear, amber-colored solid with good physical properties and moisture resistance for bonding and coating applications. Not intended for clear coating.
Warm Weather Bonding with 209 Extra Slow Hardener WEST SYSTEM Epoxy’s cure times are based on an ambient temperature of 72°F. In warmer temperatures, epoxy cures faster. Here is what you need to know to ensure adequate working time when using epoxy in warm conditions:
Epoxy cures by a chemical reaction between the resin and hardener that releases heat, called an exothermic reaction. The larger the volume of epoxy the more heat that is generated. Many epoxy users have seen pots of epoxy smoke and bubble due to uncontrolled exotherm. The good news is you can prevent this. A good rule of thumb for gauging cure speed is that for every 18°F increase above 72°F, the working time and pot life will be cut in half. To maximize the working time of the epoxy, consider how much time you need and what temperature you’ll be working at, then select the hardener accordingly. For hot temperatures, we recommend 209 Hardener.
Epoxy Pot Life v. Working Time Pot life is always shorter than working time because epoxy contained in a pot kicks off faster than epoxy spread into a roller pan (thin film). Spreading out the epoxy dissipates heat, extending its working time.
Helpful tip: Use 300 Mini Pumps to always dispense correct ratio of resin and hardener. One full pump-stroke of resin for every one full pump stroke of hardener is all you need to remember. [TABS]
Pot life at 72°F (22°C): 40 to 50 minutes* Pot life at 95°F (35°C): 15 to 20 minutes* Cure to a solid state at 72°F (22°C): 20 to 24 hours Cure to a solid state at 95°F (35°C): 6 to 8 hours Cure to maximum strength at 72°F: 4 to 9 days Minimum recommended temperature: 70°F (21°C)
*The pot life refers to a confined mass of 100 grams of epoxy