Fire Brick question for a newb

[Bruce LB]

I bought a bunch of fire bricks from a hardware store here, but then was able to score on some that were being given away. I'm not sure if I can use them though. The free ones are older and bigger. Some say "Alamo" and some say "Kimberly". Are these regular fire bricks that I can use? Thanks

[UtahBeehiver]

IMHO,

Both the Kimberly and Alamo bricks appear to be fire brick. What duty, who knows. If they are hard to cut then they are high or super duty, it they are "really" easy to cut then they are low or medium duty. It is the amount of alumina in the brick that is the main component on the duty rating and hardness, higher alumina content the harder the brick.. But free is good, you just need to strategically select where you want to use where so you are not having to cut bricks to match the other size ones, ie floor one size, arch another size, dome a different size, thickness will affect the use of the "IT" tool since, etc.