Oliver Stanton

I'm thinking of digging up the RMH my greenhouse and putting it above ground. Then I can put my compost directly on top and use it more so as a localized warming as opposed to warming the whole hoop house.

Would decomposing compost be a good mass? What are the best type of masses to use whether it be in a greenhouse or a house house or green eggs and ham.

Are most RMH designs built with mostly cob surrounding the exhaust tubing (thus most are benches?)? Or the exhaust is surrounded with sand as in paul wheaton's portable, move it & reassemble in an hour, design?


okok...I'm done

So...next time I build a RMH for my greenhouse or house house I would be better off:

1) having my thermal mass above ground
2) having it below ground but with a different substrate to cover it
3) (as #2 said and pulling off another thread) surround the exhaust pipe with a different thermal substance such as barrels of water (as in the greenhouse thread with 6-8 barrels lining the exhaust of the RMH)

oopsy...too late. But it does have a better draw. I cut two inches off the riser and also restricted the feed tube to about a third. ALSO, the more fires I have in it seems to be drying up the cob more. We will continue to see but all suggestions are certainly welcome. Thanks again and in advance to everyone!

Question: correct me if I am wrong but will covering more of my 55 gal drum send more heat below ground to warm up my 1.5' of dirt thermal mass? And covering less of the barrel will cause more heat to enter the room immediately, correct?

Okie Dokie...put a chimney riser on and that helped a bit with the draw as well as restricting the feed tube. I may need to put some sort of cap on the chimney as it can get windy here. I am going to cut an inch or two off the riser to see if that amplifies the flow.

I'll update in a few hours to let you all know if it worked.

I have a video with descriptions of everything. I would love to share them...would anyone walk me through how?

Also, to edit this post, my cob was wet when I ran my first fire and I believe that after a few days of two fires a day it has dried out. I have not yet put a thermometer on the 55gal drum but will tonight. It is operating a little bit better now but still not rockety enough. I will try making my chimney 14' to see if this helps. Secondly I will try insulating my 55gal drums with cob and see if that helps as well...? I will update soon.

(too many questions but my last one is does anyone know how long it should take to heat up the 1.5' of dirt above the exhaust?)

This thread was helpful:
https://permies.com/t/32493/rocket-stoves/RMH-smoke

Good morning everyone!!!

This is my second post here on permies and I am happy to say this post is to share with everyone my First Ever Rocket Mass Heater! (and to get some help). I just finished up the heater inside of my hoop house. It has not been working properly all the time but 90% there I believe. Had a few fires, adjusted a few things and now I need to figure out the next adjustments.

DESCRIPTION:
burn pit = 6"x8"x10"H (brick)
burn tunnel = 6.5" diameter x1.5' long (cob & brick)
Riser = 46"H, 7" D inside, 9" D outside, 1.25" insulation (clay dirt & perlite) 2" gap to inside of 55gal barrel
55 gal drums = 48" H cover only a foot up with dirt
Connection to exhaust = 12" D tapered to 7"Dx27'L exhaust (buried 1.5' under ground)
smoke stack = 6'H exterior of hoop house

FIRST FIRE IN THE HEATER:
My first fire was OK. This newbie got the flow going then the fire going BUT got smoke back as the fire climbed the logs. The heat riser sizzled and popped. Second fire was VERY difficult the next day.

1st ADJUSTMENTS:
1) Today I removed the top 55gal drum and found the perlite/clay insulation in the heat riser had closed most of the gap between it and the 55gal drum (so i shaved off the expanded clay/perlite to recover the 2" gap)
2) Restricted the feed tube air flow with a paving stone to the width of the sticks I put in and...VOILA no smoke back.


The fire is burning better now with 1 complaint. It still does not seem Rockety enough and I think it might be the heat riser diameter...Oh wise homosapiens help please.
***It has been 8 degrees F colder at night since I installed the rocket heater even with it off...I'm a bit confused***

Thank you all for the wisdom and help you have given to show me this awesome new experience! The rocket stove will be perfect for my beer brewing.

All great information! Thank you! I'm trying to experiment without screwing up my rocket mass heater riser tube. Will anything go wrong if I get my mix incorrect, fill my riser tube, and start a fire?

Will heavens fall, will bombs explode? OR will my fire SIMPLY be less efficient & less sturdy until I get my cob mix correct?

I just want to dig down 18" or so, pull out what is hopefully clay dirt (sift it, mix with water, dry, smash with hammer, mix with water then make cob) & make cob for my Rocket Mass Heater!

Good day to everyone! First post here at Permies.com and posting from englewood, CO. Working fast for a life change that continues to make me happy, self sufficient living.

One of the cornerstones to that education is COB. I have learned a lot from ernie & erica, forums, youtube, google, and forums again. Still I have trouble either cleaning my head and overanalyzing how to make cob from clay dirt in my backyard or I am just not finding a general guideline specific enough to my brain to fully understand how to make cob from clay I dig up from 18" down in my backyard.

I'm looking for that magical thread that explains A RECIPE ON HOW TO MAKE COB FROM DIRT GATHERED FROM MY BACKYARD (Or recipe for making cob from clay/dirt extracted from the ground. Need some guidance as all dirt has different compositions and as a newbie I am having trouble looking at dirt and saying "this needs more sand OR this needs more clay OR this needs more dirt from my backyard, etc). Some particulars include:
1) Testing dirt with a layer test in a mason jar (having trouble reading my results but will try again)
2) how to treat or prepare my dirt for making cob (do i have to let the clay dirt dry then crush it and remix then strain? OR do I have to let it sit in water for a month? OR do i have to treat the clay dirt at all besides getting out the organic matter, rocks, roots, etc?)

What I have done:
1) Soil tests include:
a) putting soil from 18" down into a jar, mixing heavily, letting sit. Marking sand @ 1 min, silt @ 1 hr, clay when water is clear. Still waiting but think I did it wrong.
b) Snake test: rolled clay soil from ground into a snake then a donut. Added about 10 drops of water to golf ball sized clay. Some sticking to hands as clay, some silt on hands (dries quickly and rubs off), but the snake did not go even a quarter of the way around my finder.
c) Drop a ball of clay dirt from 5': Breaks apart into several clumps dry and fewer clumps with 10 drops of water.

I live by red rocks amphitheater and could look into getting clay from there. Still learning and would love to take it out of my backyard if possible. If there is already a thread that covers these questions and you know where it is then send me a link. Any help is much appreciated by this curious, hardworking homesteading newbie.