This has been the benchmark Furnace Cement for over 90 years. Rutland Furnace Cement is a pre-mixed silicate cement that withstands temperatures over 2000° Fahrenheit without failure. The smooth consistency feathers very thin to make metal-to-metal joints smoke and gas tight. For installation and service of furnaces and oil burners. Seals flues and coal or ash pit doors. Also for small woodstove repairs.