Imperial 10.3 oz. Black Stove & Fireplace Mortar. This direct vent seal is excellent for sealing the firebox & venting joints of gas, pellet, corn & wood stoves. It resists temperatures up to 2000 degrees Fahrenheit and is paintable when dry. Air cure with a drying time of 24 hours. ASTM E13679 Specified. Use for repairing cracked and chipped firebrick and tuck pointing mortar into damaged masonry-to-masonry joints where cracks are 1/4 inch or less. Non-asbestos, great bonding strength. Durable as firebrick when heat cured.