The burnstack is firebrick, wrapped in 1 inch unitherm ceramic insulation. The unitherm insulation is held in place by a couple of strands of wire, then I wrapped with metal mesh that is used for stucco. I think this is good to go, but need to decide if I need to clad the stack in fireclay. The fireclay mix would adhere nicely to the metal mesh and might protect the metal mesh, but I am not sure if this step is necessary.
another look at the burn stack, this time looking down at top before I wrapped with the metal mesh.
Cleanout at the beginning of the run back toward the burn chamber. The fan idea is gone.
Wrapping with left over unitherm, then moving back to build up with fireclay and cob mix.
You can see the ductwork/riser to left and behind the burnstack. It will come out of the cob with a heavy 8 inch single wall stove pipe, then reduce down to 7 inch black stove pipe and runs about 5 feet back and slightly up before it does a 90 degree turn and into the brick chimney flue.