Eliminate the cost and hassel of a poor sealing fireplace reline base plate! Instructions:
Pour a bag into a 5 gallon bucket. Add phosphoric acid (provided) mix with drill and paddle mixer.
Pour down flue on top of Cera-Foil blanket.
Plugs within minutes depending on ambient air temperature.
Refractory foam will rise two times its volume forming a hi-temperature, solid positive seal.