This a 8" j tube about seven years old and it works like a dream but it's not at all pretty so I cover it with crochet pads made from old tee shirts. It's in constant use when it's cold and I've cleaned it out a few times and repaired the cob around the burn chamber twice. I'll finish it one day.
I built it, Fabrice reluctantly built the chimney core and cut and helped with lifting on the old heavy water heater I used to surround the chimney and insulation (Perlite). He didn't believe it would work.
I used an old chimney pot to connect to the barrel which was easy to cut to size and I also cut out an inspection hatch in it. I used the top of the chimney (Which I cut off) to go into the the cob near the barrel and it's used to dry things, warm wine and so on.
Water heater on, burn chamber cobbed in
Experiments with exterior air to burn chamber. I decided that this didn't make much difference the rocketiness and adding another metre to the height of the chimney solved the problem of a good draw.
Second firing, it worked well (inspection hatch covered temporarily until I had cobbed the bench)
Inspection of the joints and cob around the bottom of the barrel after a few burns
Inspection hatch covered with a plate from an old stove
Plan of the workshop. The rayburn heats the water, I preferred to use the rocket for heat only as the pipe run was so long
Just before the pipes exit to the chimney, a boot stash in a dark corner near our back door with a 1 watt LED light which comes on automatically when you come in to take your boots off.
A good clean and repairs to the burn chamber after 5 years
Four dogs, a man, two cats and me and the rest of the dogs are further along the bench...