I need to install a cast iron chimney clean out door into an 8' x 8

For setting a fire or ash door you would normally use a factory mixed refractory cement (fiber reinforced sodium silicate - based fireclay) that would withstand 2000°F + heat. This is the same mortar you would use to set and line the firebricks or repair cracks in a masonry fireplace. It comes as a dry mix or a ready-to-use mix.

Rutland (

) is one of the most prominent manufacturers here in US and in my neck of the woods I'd go to a Tractor Supply store for it, or order online:

  This particular product, Chimney Sweep® Furnace Cement is just what the doctor's ordered, I've highlighted the parts from the manufacturer's description that would be especially of interest to you. Picture attached below.

<q> Chimney Sweep® Furnace Cement is a pre-mixed, heavy bodied, high-temperature silicate cement that resists temperatures to 2700º F. Especially suitable for bonding and sealing metal to metal joints Makes masonry to metal repairs easy

Repair or reset furnaces, wood or coal stoves and fireplaces

18 month limited manufacturer's warranty  </q> read more and respond »

Posted 5 years ago by homeowners in Concrete

Report misuse