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Monthly Archives: February 2019

When last we saw the rocket stove, after test firing one… (descriptions are set to E.E. Cummings?)

Rocket Stove Stress Test

When last we saw the rocket stove it had gone through core/chimney test firing, then had been wrapped with rockwool inside a hard backer-board shell trimmed with steel. It awaited the stainless steel drum.

Test fire two. Stainless steel drum over chimney.

Here the drum is in place fitted over the inner chimney riser, with two vents of stainless steel pipe securely welded near the bottom of the drum. The drum radiates heat to the room, and vents the comparatively cooler air near its base, creating draw on the chimney by dissipating heat quickly. The vent pipes are fitted with double wall stovepipe vent, increasing from 3 inches at the drum to 4 inch vent. This rear vent is the main riser to the house chimney, and the other will feed into and through a mass form (to be built in-situ at the ranch), this mass-venting line will link back into the main riser, ensuring a continuous hot draw out the house chimney, as well as a strong draw through the mass.

Two vent pipes welded on, with stovepipe ends.

Running with no visible emission or smell of smoke for 40 minutes. I need to verify that the rockwool liner survives a high heat and keeps things air tight, that the outer drywall board remains stable, and that the metal frame stays cool. The stainless steel drum begins to turn copper color with heat, as it should, but the box is cool to the touch. Time to test to possible failure.

40 minutes into the burn, running it hot.

I pack the firebox with 1inch diameter pine and 3 inch branches, and the chamber, already over 1000F, devours the wood straight into a white light. Temperature at the chimney, with o2 blending into the gas reburn venturi-vortex, jumped to over 1500F or more- and suddenly a putrid heavy black smoke churned from both vents. It was similar to foundry fails, when molten metal is poured into a mold that hadn’t burned out completely, and the metal annihilates everything not burned out and gasses out the uncured mold- in a vertical jet of putrid flame. This wasn’t anywhere nearly as dramatic, yet I recognized the smell of things coming apart in high heat. The black chem-smoke would dissipate, and I would repack the box, and the black would bloom again. After 20 minutes the worst was over, and I pulled out the remaining big branch, and replaced it with a 1×2 x two foot run of oak. This hardwood will burn hotter, and burn very clean; soon things were running back at “zero emission” again.

Tree branches vaporize in the chamber.
The connective welds (bronze weld to stainless steel) heat to rainbow color.
Oak end-cut for a clean burnout.
Chimney removed, core and rockwool are perfect
The chimney is a fail.
Chimney view. Shrunk, crazed, and vitrified: well over the 1200F rating at base and ruined, cooler at top and the ceramic is fine.
Rocket stove tested to high heat, and ceramic fiber inner chimney fails. It shrinks, cracks, and vitrifies to a weakened state.
Outside SS wrap wire is fine, AL wrap thinned to parchment or gassed off, ceramic destroyed at base.

I have already ordered ceramic fiber board rated to 3,000F, same as the unscathed core-box, to rebuild the chimney. I wanted to try the round chimney, even though it’s temp rating was only 1200-1500F as it allows a stronger spinning venturi-effect to cleanly re-burn all the gasses. Looks like I’ll be going with the square version made from fiber board. I’ll post how the retest goes soon.

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Overnight snowstorm is waist deep on 1/2 life size operator of the waterfall weir.

Last night we had our biggest overnight snowfall in more than a decade, with 15 inches at the house and 20 inch drifts. In the mountains; 5.5 feet at Alta resort.

Nora and I walked to the park yesterday and it started spitting snow, but nothing stuck ’til around 5pm. I shoveled a few inches before nightfall, clearing everything before E got home from work (I’d just picked up and stacked another 1000lbs of bricks picked up from a nearby house remodel for redoing our winding pathway in the back yard this spring).

This morning I had a cup of Joe and headed out to tackle shoveling. It took me nearly an hour to clear a path from the truck to the street, as I had determined I couldn’t clear the path all the way back to the garage to access E’s 4×4 Subaru in time for her to leave for work, so I planned to drive her to work then come back and keep shoveling. A neighbor let me know all schools and gvmt offices were closed, just as E came outside. She checked in and sure enough, Snow Day! So I kept shoveling, and shoveling, and shoveling. I have an oversize shovel made to push up a big bite, then slide snow out of the way to dump elsewhere- which works great with this California Concrete. I just have to stomp out a path to dump the snow, then grab a big shovel full and cart it over and start ramping up; to five feet tall by the entire length of the driveway. And another big pile at the foot of the drive out by the street.

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It came from the Northwest.

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Couples with matching outfits can be a bit much.

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Birds perched on her just yesterday.

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At least a foot, plus drifting. It started wet and warm from the South with nothing sticking ’til late afternoon, then shifted to a Northerly in the wee hours of the morning and fluffed powder up on top of the slushy scrubble. (410 road accidents so far)

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Nora has never seen a snow wall taller than herself before.

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I cut this little path with my flat shovel. She tries it out, and thinks it’s pretty keen.

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Three hours of shoveling later; the last time this bit of lawn had such a pile it took multiple storms and Lucky was encased within it- many Xmases ago (2016) when Walt & Kaye & my mom were here. I gassed up my neighbor’s snowblower, and he did my front sidewalk and toured around the block a bit.