22 CAULK is ideal for filling joints and cracks in refractory linings. Job site mixing is not needed. Just snip-off the tip of the ready-to-use caulking tube and apply the moist material using a hand or air powered caulking gun. Heat loss through joints and cracks will be reduced. Fine particles will not accumulate in those openings, preventing further damage to the lining. The surface of 22 CAULK will harden when exposed to air.