In the last months , I start thinking about to build a ceramic oven ( to bake ceramic or melt metal ). The beginning of this is to have firebrick. Instead to buy it , I start to searching about how to make it ! After many try of different recipe ( some coming of from my mind , others seen from internet searching ) , I finally discover my best recipe. Like I said in the video above, I use a mix of clay ( digged out from my backyard and purified with a process a see on a website ) and perlite. The mix ratio by volume is 1 part of clay for 2 parts of perlite. It’s give a strong enough firebrick , light weight and good heat isulation. The brick I made in the video is split in half because I made with it some strenght test ( dropping it on the concrete floor at 4feet few many time ).