This fireplace mortar is an excellent product to tuckpoint between firebricks and repair broken firebricks. Maximum application thickness is 1/8". Withstands temperatures up to 2000F. Not for exterior use.
WARNING: Carcinogens: This product can expose you to chemicals including Lead, which is [are] known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.