oldnumber12

Seems to be a worthwhile experiment and I should have enough material to try it both ways, I'll post the results.

I'm looking to build a gas forge, nothing spectacular.  Researching this site has proven to be a considerable asset, giving me alot of insight.  Having not seen any reference for the substitution got my curiosity up enough to ask. 

I am assuming either sawdust or charcoal would turn to ash when heated to the higher temperatures of a forge.  My thought was having smaller voids from the screened charcoal might have less impact on the structual integrety of the brick.  Don't know for certain, I'm fairly new to blacksmithing and have limited knowledge of many aspects of it.     

Since I haven't seen any reference to it, I'm curious if anyone has substituted hardwood lump charcoal for sawdust in their firebrick recipie.  I've been experimenting a bit and found it is fairly easy to pulverize/grind down small enough to pass through a window screen.  My uneducated theory being it might create more uniformed micro pores in the firebrick, still giving it an insulating value and help to maintain a stronger firebrick.  Would appreciate any thoughts on this subject.