Im using a refractory Plastic Fireclay Premixed Mortar for Firebrick Called DEMON Mortar Mix made by Plibrico Purchased in a Pail. This stuff seems to take quite a while to set up and then if exposed to moisture the next few days it seems to take up moisture again and become more pliable Does this stuff require higher than normal summer air temps to fully cure? Anyone familiar with this stuff It was purchased from Alsips in Winnipeg the largest brick and refractory place around Quite expensive about $40.00 a pail . Hope its the right Stuff!!!