Re: HeatStop II

Posted by Rado

In Reply to: HeatStop II posted by Eugene

"... and use this stuff only for a small part closest to where the firebricks touch. Does that make sense?"

Yes it does, he meant where the bricks touch there is very little gap thus very little mortar goes in, bond starting from inside half way out. It is a fine-paste-like mortar used only for thin layer applications. (Fireclay mortar is very coarse as it has large amount of sand in, not fine, this sand makes it to shrink less.) You can do what he said if you go with this sort, wait till the mortar in arch hardens and fill the rest on outside with mixed at home fireclay mortar.
Same commercial stuff could be used to fill also the second outside half but with many fragments from broken firebrick or terracotta clay pot or roof tile pressed into the fine mortar. Like wedging, it prevents shrinkage of this fine stuff. Picture shows bag of fireclay. r