MAS Medium Hardener is a polyamine blend intended for moderate reactivity and resistance to amine blushing. Moderate pot life, gel, and thin film set times provide advantages when filleting and fairing. MAS Epoxy/Medium mixed with thickeners, gel and set quickly enough to avoid draining and sagging, while still allowing ample flow time for controlled application periods. We recommend this hardener when "overnight" sandibility is more important than continuous laminating and open time (as provided by MAS Slow Hardener) MAS Medium will also provide a beautifully smooth void free finish, with great resistance to milking out during application and fogging in critical clear coating applications. MAS Medium's cure speed may be adjusted by the addition of MAS Fast or MAS Slow to Medium hardener. The 2:1 mix ratio of resin:hardener should be maintained regardless of hardener blend. STORAGE LIFE: A minimum of 12 months in a sealed container at ambient temperatures. Caution: You may find amine blush on the surfacce after cure. Wash it off with plain water, ONLY, and let dry thoroughly before recoating.