West System 205 Fast Hardener

205 Fast Hardener is a medium-viscosity epoxy curing agent. It is used in a majority of bonding situations, at lower temperatures, and to produce a rapid cure that develops its physical properties quickly at room temperature. When mixed with WEST SYSTEM 105 Resin in a five-part resin to one-part hardener ratio, the cured resin/hardener mixture yields a rigid, high-strength, moisture-resistant solid with excellent bonding and coating properties. 205 Fast Hardener is not intended for clear coating.

West System Epoxy cures by exothermic (heat) reaction. Be sure to mix in larger containers with more surface area and mix in smaller batches. Mixing in large batches or containers that are too small can cause a dangerous heat reaction and will cause the epoxy to cure too quickly.

Working with 205 Fast Hardener in Cold Weather
In cold weather, use 205 Fast Hardener to cure well at temperatures as low as 40°F. There are several things you can do to ensure a full cure when using epoxy in low temperatures:

• Warm the resin with heat lamps.
• Build a small portable hot box out of rigid sheets of foil-backed insulation, with a regular light bulb or an electric heating pad inside to maintain a temperature of 70°F–90°F.
• Keep the resin indoors before use and then transport it under a heating outlet.

In very warm weather, use 206 Slow Hardener or 209 Extra Slow Hardener with 105 Epoxy Resin.

The 205 Hardener will amber over time; if you're looking for a water-clear epoxy, choose the West System 207 Special Clear Hardener.

Group Size A Hardener - use with 105-A Resin

Group Size B Hardener - use with 105-B Resin

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.