Tiny House 6" Rocket Mass Heater

 

Source for clay, clay, and rocks on their support.

Notes: 

-The rocks hold heat well: at 5:30am the rocks are 12 to 15F degrees warmer than the rest of the interior.

Burning the paint off the barrel

Sand, clay and water.

the metal riser was a mistake....metal burn tunnels, feed tubes, and risers will burn out in one year or two of usage.  Only specially designed 4" systems can use metal without this issue. check this site out for changes in technology to RMHs DIY Rocket Mass Heaters DVD

Firebrick, high temperature mortar, and 6" pipe: J tube almost complete.

J tube ready for barrel.

Barrel on J tube and cob 75% done.

Things learned on this build:
 -the feed, throat, and j-tube's geometry should be symetrical for a perfect burn...my first build, see the older rocket stove build, was built perfectly symetrical and it's smoke smelled like steam instead of smoke (indicating a perfect burn). This current build is not a perfect square, but rather the feed and throat is rectangular resulting in output smoke smelling faintly like smoke which indicates failure to burn perfectly;
-cement backer board doesn't hold up to flame or coals very well;
-high temperature fiber cloth doesn't hold up to orange hot coals very well.

Temperature Data on the Rocket Stove:
Highest recorded temperature on top of the barrel is 432F

***Update 20190118

erm, so the rocket stove had to be modified so that I had an air gap between the rocket stove's base and the wooden floor (obvious yeah, but I thought ceramic tile and thermal blankets would do the trick -nope.) To do this I got a 1/4" steel plate (with legs), the entire J could set on; took off the barrel, lifted the J onto the plate with legs, rebuilt parts of the J a which came unmortared, rebuilt the clay base, put the barrel back on, and clay sealed the entire assembly.  ....Sounds easy??? try water, clay, and sand in 40 degree weather with out heat.

The steel plate modification cause an unforseen issue: I can only run the rocket stove for about three hours before the throat becomes hotter than the vertical part of the J tube. 

This limit on the rocket stove means my heat sink, the cob bench, takes a morning and an evening burn over more than two days to get the bench up to 80 or 100F.  Since I don't have four to six days off to get my cob  bench heat sink up to temperature, I cannot really test how long the cob bench lasts between firings.

I still can heat my entire building for eight hours with a small  bundle of sticks (due to the fact the rocket stove by design gasifies the wood and burns the gas too).

I am now looking at a batch mode rocket stove which would fit the life style of a wage slave such as my self at the moment.  Batch mode means no fire tending.

Clearly any one can build a rocket stove however, it is much trickier to build one that runs at maximum efficiency .....check out the video download here:

$15 if you want to build one that works!

***end 20190118 update***