[TheForge] propane forge

[Gladish Family]

Speaking of forges, is there a reason to make forges cylindrical?
I have plenty of cylinders lying around, but rather than get into the
trouble and expense of ITC, I think I'll make a steel box, line it with
Kaowool for insulation, line that with firebrick for refraction, and stick a
blown burner in the top.
Is there any way to tell in advance whether the firebrick I have will
reflect heat? Or is this trial and error?
Andy G.