16 oz. Gray Hi-Temp Stove & Furnace Cement. A heavy-bodied silicate cement that withstands temperatures up to 2700 degrees Fahrenheit. This durable cement bonds and seals metal-to-metal and metal to masonry joints under 1/8 inch, making it ideal for repairing wood or coal stoves, furnaces, fireplaces, and flues. It prevents air and gas leaks in flue and chimney joints, meeting or exceeding ASTM C 199 Pier test standards.