PreMix for the People Heat Stop refractory mortar
With PreMix Heat Stop, the mixture will stay good for as long as the lid is reapplied. Product Details. This refractory mortar is gray in color and is shipped in 15 lb. and 50 lb. plastic pails. For estimating purposes 50 lbs. will lay up approximately 100 firebricks (2 ½ inches thick) if joint thickness is 1/16 inch to 1/8 inch as recommended.