Firebrick - Purpose and science

[karri0n]

Hi all,

I have a few questions regarding firebrick. A fair amount of the Firebrick in my stove is cracked/broken, and I plan on replacing it. I'm wondering, what is its exact purpose? I know it either has to do with heat transfer or insulation, but I don't know which. Is it for reflection, retention, or radiance? What is the importance of replacing it if it's cracked or broken, and what results can I expect when putting all brand new stuff in there?

 

[Todd]

It's mostly for insulating the firebox to get the temp up to secondary burn temps and create that clean efficient burn.

 

[fossil]

Seems to me that firebrick is likely also part of the system of insulation (along with external shields) that allows the reduced clearances of many of the modern stoves. It also serves as the baffle in some stoves. Definitely serves to keep heat inside the firebox. In any case, it's an integral and important part of the stove as a system, and should be maintained in good shape. Rick

 

[Wrigley]

Replacing the cracked/broken firebrick will not significantly change your stove's performance, it is just part of good regular stove maintenance. The brick is thermal mass that helps the stove build and retain heat while protecting the metal from the most intense exposure. If the bricks are broken to the point that you are missing decent sized chunks, or the bricks are missing altogether, that's another story. The firebrick is integral to the design and normal operation of your stove and should always be in place as a simple matter of safety. Bricks with just cracks do not usually pose any danger. But firebrick is relatively cheap and easy to replace. If you need to cut bricks to fit a masonry blade that will fit a circular saw runs about $5 at the hardware store. Just make sure you cut outside -- this makes a lot of dust!