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 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 or with .
The 205 Hardener will amber over time; if you're looking for a water-clear epoxy, choose the West System .
Group Size A Hardener - use with
Group Size B Hardener - use with
Helpful tip: Use 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.
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Specs
Pot Life at 72F (22C): 9 to 12 minutes*
Cure to a solid state: 6 to 8 hours
Cure to maximum strength: 1 to 4 days
Minimum recommended temperature: 40°F (4°C)
*The pot life refers to a confined mass of 100 grams of epoxy
Video
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