Meeco's Red Devil 1/2 Gal. Buff Refractory Furnace Cement . Packaging may vary. A pre-mixed, fiber-reinforced, high temperature silicate mortar for setting, coating or repairing firebrick. Used extensively as the mortar between firebricks when building fireplace fireboxes. The ideal high-heat sealant for masonry-to-masonry joints less than 1/4 In. thick. Effective in resetting and cementing furnaces, stoves, chimney collars, boilers, and duct work. Not intended for exterior use. Pack of 2.