I have been guilty of that and I have seen the error of my ways. The combustion chamber (sheet metal) in my rocket stove has burned out with less than 20 to 30 hours of use and has made the stove unusable. Sheet metal pipe and fittings will not put up with the temperatures for long. But as it was only a prototype I will rebuild!!! I will working on a new "heavy metal" combustion chamber and riser design with all new drawings.
Wow!!! What a rocket stove!!! Do you have any drawings for your rocket stove. Maybe Height and diameter of riser? Type of insulation? Pictures during construction? Did you weld it yourself?
This summer I plan on building a much smaller down sized version and will play around with having a way to use it as a rocket stove and as a normal wood stove, I would like to be able to throw a load of wood in the fire box and have it burn through the night after going to bed.
I have been thinking about longer burn times, how about a sawdust filled coffee can as fuel for your new rocket stove? Please see http://www.youtube.com/watch?v=Qj7X9X8LTe0
Mount the coffee can under the insulated riser, the flame seemed robust enough. Or maybe build a rocket stove riser and exhaust chamber using a 16 gal drum onto the lid of the large sawdust stove. Wow 8 hour burn times and rocket stove too!