UPDATE: Unfortunately, this rocket stove design has proven to be a failure, and I have since deconstructed the stove. I cannot recommend that someone follow these plans. You can read my original post below for what not to do, though.
The rocket stove and cob bed and bench are essentially finished. The rocket stove (which I will detail more in yet another post) has 25 feet of horizontal run that wraps through the bed, into the bench, and out the southern wall of the house.
Laying out the flue pipe
Before making the cob bed, I laid out the stove pipe and propped it up on pieces of urbanite and brick, and then I leveled it. I sealed the joints with aluminum tape to help keep everything together. After I decided that the stove pipe was level, I started adding rubble (pieces of urbanite, brick, stone, and old cob) to the bottom of the bed, underneath the pipe. I wanted to add as much filler as possible to avoid having to make that much extra cob.
Sculpting the cob bed
Next, I began making cob and sculpting the bed. I used a ratio of three buckets of sand to two clay, with a slightly lighter amount of straw. (Sand provides the heat storage capacity of the mass, versus the clay which just binds the material together.) Along the wall, I stuffed some light clay straw (straw lightly coated in a clay slip) to help create a kind of insulation buffer between the bench/bed and wall. I cautiously cobbed around the three ash cleanout holes so that the lids could be easily removed and my arm maneuvered into the pipe.
The bed and bench took something like 20 batches of cob to complete. (That’s almost 1/10 of the material it took to build the house itself!) Surprisingly, it was pretty quick work. I kept the rocket stove burning to help dry the mass out as I added new material. The bed half has about six inches of cob on the pipe, which is quite a bit more than I would have liked, but it needed to be that high to meet the top of the T joint cleanout. The bench has about two inches of cob on top of the pipe.
Miso storage under the bed
Alongside the bed, I carved out two storage nooks. I sized the nooks to fit a five gallon stoneware crock so that I could keep fermenting foods warm while the mass is heated. (Fermented foods like miso like warmer temperatures.) As you can see above, the pipe is very close to the back of the storage nooks. (Might this be the first bed with miso storage built into it?)
The cob bench
The cob bed tapers into a bench that curves around the south and west walls. This little sitting area could probably seat about four or five people. I’ll get a table in there to make it more of an inviting hang out space. It might make for a nice place to sit and eat meals or play board games, especially.
Of course, the bed and bench will get a final plaster treatment once it’s all dry. Eventually, my plan is to make either a homemade wool or straw-stuffed mattress for the bed half of the mass. I am definitely excited about sleeping on this thing…