Glenn Herbert wrote:Fire clay is what you want. Hawthorn Bond is a known brand. Aside from heat resistance, fire clay has the property of not expanding or contracting much with temperature changes, which is important in riser construction.
Casting the core with space for firebrick liners is good, though you don't need to worry about the back half. Unless you are rough with things, only the feed tube and floor will be subject to abrasion. Wood does not get loaded into the burn tunnel except as coals spill out into it, and ash cleaning is a very minor and gentle procedure. I use a sardine can mounted on a short handle to scoop ash, takes a few seconds once or twice a week.
Great information, my first go around will be for a garage and a simple J-tube configuration, so I will take your advice on the fire brick being used towards the front only. The final build that I will put in my small home (building in the next couple years) will be a batch box and I will be lining most of that with a commercial fire brick.
While we are on the topic, How large of a batch box could one make? Is there a point where the material is too far away from the entrance to the riser to work properly?
