MID-CUREâ ¢ 15 min. epoxy is used in larger areas where more working time is needed. It is more water resistant and can be used as a substitute for QUIK-CUREâ ¢ in most applications. MID-CUREâ ¢ is our most flexible epoxy and is ideal for gluing to fiberglass surfaces. Allow 45 minutes before handling parts and 2 hours for full strength. 4.5 oz.