Kos fire cement is a ready mixed blend of thermo setting resins & inorganic fillers that cures when exposed to heat, resulting in a mortar which is resistant to temperatures up to 1250â°c. Can be used for domestic & commercial applications on fire bricks, fire grates, flue pipes, flue bricks, boilers & other applications subject to extreme heat. offers excellent adhesion to fire bricks, blockwork, stone & clayware, asbestos free.