Rocket Mass Heater install!

Danger is as surprised as you are to see this contraption out of the truck and in place, with the old 300# wood stove moved off.
On the left is the J-Stove with its stainless steel barrel radiator, and on the steel bench is the mass heater. This will be their first time being connected, if all goes well.
While Danger test-fits stovepipe; The mass heater weighs about 130# and was lifted into the truck in SLC with an electric 1-ton hoist. To remove it, the steel bench was cinched to a dolly (flat) which reached the height of the tailgate of the truck. The truck was backed onto the concrete platform outside the kitchen, and the mass-heater was slid out of the truck onto the bench/dolly combo, then the bench and mass-heater were separately cinched. Then it was all rolled through the house. Once in position at the hearth brick, the dolly cinches were removed and the payload was tilted up and slid into position. E helped Danger by stabilizing the load as well as his mental stability.
Nora is so done with all of Danger’s stove tinkering. She had hoped it would all stay in SLC, but no, here it all is in Montana, and her big cast-iron stove is standing cold at her feet.
Butterfly on the main riser dampens the flow (it is open here), directing more heat into the secondary riser fitted to the mass heater.
Danger’s theory of on-site craftin’: bring bunches of stuff and fiddle till it fits, then return whatever is left.
Danger measured and measured and measured, making sure the steel bench would be just lower than the J-Stove. He welded big nuts with riser-bolts into the feet of the bench to raise it and align with the J-stove. Danger’s measures were high by 1/2 inch, and the J-Stove is now mounted on bricks and Danger is glad he put in 3.5 inch riser bolts, though it seemed overkill at the time.
Danger finds Lyle’s big wrench set and deploys the extension bolts.
The double wall pipe from the mass heater points a little bit down, as the concrete floated the tubing juust out of alignment- Danger thinks he can snug it together though.
Snugging the stainless steel pipe into the double-wall stovepipe. It all fits. Whew!
Danger recovers his mojo by making a creative solution to the too-long 8″ to 6″ reduction stovepipe coupled to a 6″ to 4″ reduction. He sleeves the 6/4 inside the 8/6 and it aligns perfectly to the T pipe on the stove, so he lines it with stovepipe caulk, then screws it together with self-tapping metal screws. This part is then calked and screwed into the existing 8″ stovepipe protruding from the wall.
The double-wall T connection with bottom dropout/clean-out is affixed to the stove.
Stove connected to mass heater: check. T connector bonded to stove: check. Chimney pipe connected to reduction: check. Now let’s tinker-toy it all together!
So close! I need just a little extra part of something…right there by the drill! (Left side mid photo)
All fitted out!
Now I loosen it all and seam inside the connections with stove pipe caulk. Then I wrap all the seams with heavy duty AL tape.
Time for a fire biscuit. Not for you Danger! Feed it to the stove.
I made a bunch of these little fire biscuits; formed of wood-chips (from the pet store), paraffin wax, a flat cotton swab, and perlite. They stay lit in wind, which is a must within the J-stove.
“My biscuits are burnin’! My biscuits are burnin’!” -Yosemite Sam-
Fire is go!
The fire will only burn at the bottom, within the stove, allowing long staves to slowly burn down into the beast.
Split firewood needs to be split small to fit in the inferno.
I brought all the piping parts to draw air from the basement, and set that up as well. The stove draws hard, and otherwise would pull sub-zero outside air through the house.
I added the steel throat, slung into the mouth of the stove at an angle to direct wood in and protect the firebrick maw. There are two air openings for the outside of the steel, pulling the air down to the low foot of the fire. There is another air port pointing down at the center providing air to a custom channel that leads to the base of the internal riser stack where superheated gasses are ignited. The stove is near to zero emission.
You might wonder; how can you split firewood down to size to fit the steel throat? Ask New Zealand, they have a great answer: this handy and precise manual kindling splitter.
The little mallet does 90% of the load, and the bigger mallet is the convincer for any stubborn bits.
E and I brought in a few wagon loads of broken discarded corral lumber, the Kiwi splitter made super-long staves of it- and it burned down nicely.
E makes fresh peanut butter cookies to keep me off the fire biscuits.
Xander and E both display symptoms of feline Stove-Syndrome.
After creating an air-baffle with rockwool around the air intake at the steel throat, we thought it might like some dressing up. E recommended “pressed tin” from Home Depot.
It matches the deepening bronze colors of the stainless steel radiator drum.
A tidy surround.
I had made an air-tight lid for capping the steel throat, and restricting the airflow to the draw through the tubing from the basement. It was dressed out as well, and I scrounged up this old ceramic insulator as the handle/weight.
Cap in-situ.
Like a fancy cake.
Well, this is all just getting a bit too fancy for the ranch.
Skinned all the way around.
Our near zero degree nights were pulling heat out of the mass in a matter of hours, leaving it stone cold by morning. So I made it this nice blanket of rockwool. That helped a lot.
The blanket got a temporary cap matching the stove, as the mass heater will eventually be skinned in stone and have a flagstone cap. Another tweak (not picutred): driving 28 giant corral screws through the mass heater (air-crete is similar to styrafoam in density, and screws jump right through it) to penetrate the interior piping, and sealing their heads with piping caulk. These became immensely hot, quickly transferring heat throughout the mass. This means less time burning wood to charge the mass, and much longer heat retention as the heat is more thoroughly dispersed.
80% less firewood. Near 0% emission. Immediate heat, with immediate feedback on level of heat desired with in-line butterfly and amount of wood. No carbon dioxide back-venting at night. No fire at night, so no danger while sleeping. No carbon build-up in the chimney. No smoke smell permeating everything in the house all winter. No visible smoke out the chimney, and little smell of smoke outside. Plus, it is fun to feed.

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