Incidentally, if I have put this question in the wrong area of the forums, please let me know and move to the correct area if so.
Those heavy bricks are unbeatable at heat storage, so you'd do much better to incorporate those in the mass.
By any chance, is the colour of these bricks a dark purple?
Carol Morgan wrote: I believe the general consensus of opinion is that metal isnt that brilliant for the construction of the burn tunnel and heat riser, and most people tend to favour bricks.
You did not mention the clay / perelite composite core . . . made from one large piece of duct work, and one smaller piece of duct work . . then fill the space with clay/perelite .. . when you fire the stove, it turns into a fired porcelin.
You can always use the bricks for your mass / heat storage . . .
Carol Morgan wrote: In terms of using metal in the riser, does the metal stay intact or is it sacrificial? If sacrificial, do the exhaust contain gases given off by whatever metal I might use?
As you can see in the pictures I first posted, I used galvanized piping to build the core or riser of my rocket, and yes, once your stove mass dries out, and everything gets running nice and hot, the inner core just flakes away . . . leaving your baked core intact .. . I am sure there is some off gassing when the inner core is cooked, but the outer surface of my core is covered with a fine white ash . . . so I don't think the outside of the unit gets hot enough to off gas. . .
NOTE : If I am incorrect on this one, I am sure someone will correct me . . .
Here are a more pics for ya .. . what I found inside the J tube after a nice HOT burn . . . .. the inside of the riser (you can see where I packed the clay too hard and made a "bump" on the inside surface . . . .. . and outside of the riser . . .