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RMH for Dummies! Please help guide me through my first build!  RSS feed

 
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Hi Stacie;  

IF you really have to much draft... and i'm not so sure of that yet.  Then Max's idea is a good one. Here's how a bell and plunger would work

Where your current exhaust pipe leaves the mass, instead of it connecting directly to your outside chimney you would build a brick box . your mass woulds vent into  that box(bell).  Meanwhile your chimney is then plumbed into the same box but with a section  or two of stove pipe would extend (the plunger)towards the bottom of the bell. Your rocket vents into the bell, the hottest air rises and the cooling air sinks where it gets drawn into the outgoing chimney. When he mentioned an adjustable plunger ,that is a sliding pipe (won't work with your set up) that starts out high in the bell to get the draw going and then is lowered down to maximize how much heat is staying inside.

I think you need a bunch more fires to decide that you have too much draft.

Your firewood needs to be much smaller to start with. When I mentioned free Pallets I was very serious,  a lot are hardwood ,all are free and they are very dry thin wood.  Rounds of any dia are just going to start harder.  Save them for now or split them down.

Your stove did super awesome for a first burning !!! Way better than I warned you about !  Way better than my first rocket did!  We are Proud of you and your accomplishment !  Don't stress this draft thing.  Learn how your stove lights. Dry that mass out.  Get smaller wood , take temp readings .  You GOT THIS !
You-Got-This.jpg
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The Way To Go... just speed up
 
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Today I have dubbed it the "Bad ass rocket mass", affectionately. 

I combined some suggestions (Satamax and Thomas) on getting her started, and it was lit in no time.  Fire did almost go out, but then I got it going again.  There were waves  (and noise) of strong gusts of pulling air; I kept looking for wind outside, but it was still.  Not sure why this happened...?
I climbed onto the roof (many times) and kept sticking my nose in the exhaust; I am pleased to say that I achieved clean burn and mostly steam! (Paramount to this tree hugger.)
After a solid hour of burn time, I took the following temp. reads:

Barrel side:  170 degrees F
Barrel top: 250
ducting:
     direct out of manifold: 110
     after first 90 degrees: 90
     after first 180: 84
    after second 90:  80
    before chimney: 76
vertical stove pipe:
       at 1 foot: 80
      at  2 ft: 85  (multiple reads, think the spike is do to heat transfer from the barrel)
      at 3 ft:  82
      at the ceiling: 78
Mass on either side of ducting: 64, 67
Out chimney (roof) 63

Thoughts: 
   1) I feel better today after the second burn. 
   2) There is a very strong draft, I am not sure if it is going to be a problem.  (Any thoughts based on my temp readings).   I have put off cobbing in fear that I will need to change something.
   3) The fuel feed looks like a toilet, so some fancy cobwork/sculpting needs to happen
   4) I need to get busy with my lot of disorganized wood.  Sorting, cutting.  Small tinder is something I did not anticipate and need to accumulate. Worried that I may not have enough.  I have read so much about the importance of "good quality firewood" that I feel some trepidation about putting "unclean" fodder (pallet wood) in my B.A. heater.
   5) I am wondering how all of that bench mass will get heated up by 80-90 degree ducting.  AND how much wood that will take.
    

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How long did the fire burn before taking the measurements?  The initial observations of mine, seems like it takes forever for the firebricks to warm up, and then once they are hot, the ducting temps start to climb.  Those IR temp guns don't work well on shiny surfaces like HVAC ducting.  For about the first twenty minutes I can hold my hand on any section of my ducting.  After that, most sections are too hot to touch. The pipe that leads up and out the roof, I can hold my hand on that one for almost an hour, after about an hour of a rip roaring fire, then the chimney pipe gets too hot to touch.  I attribute it to the fire bricks reaching temperature.  I lit a fire yesterday and when I went to start a fire today almost 18 hours later, the bricks at the roof of the burn tunnel had just a touch a noticeable heat to them. 

I bet after a longer burn, your temps will come up a quite a bit.....and the smaller the diameter the wood, the greater the surface area, and the hotter it will burn.


Less then 20 minutes ago I just smoked my house out with mine!  I had put some green osage orange  cut less then 3 weeks ago, that had been rained on for 2 days in the stove......I know, I'm a moron, not sure what I was thinking but I wanted to test the limits/potential. Well most of it went ahead and burnt as long as I had other decent wood in there.  I ended up with a piece left in the wood feed that was just kind of smoldering.  I wanted to go to bed so I placed two fire bricks over the opening and closed it off.  That was a second major mistake.  Within 5 minutes the stove was now running backwards smoking up my house!!  I removed the bricks and it became and even worse situation.  In a panic I ended up shoving newpaper in it and lighting it and then it started to burn in the correct direction but not super great, I then had to fill the wood feed up with known good fuel and build another hot fire to correct the concern.  It's running good again, but it will be some time before I feel good about going to bed!
 
Staci Kopcha
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Eric Hammond wrote:How long did the fire burn before taking the measurements?  The initial observations of mine, seems like it takes forever for the firebricks to warm up, and then once they are hot, the ducting temps start to climb.  Those IR temp guns don't work well on shiny surfaces like HVAC ducting.  For about the first twenty minutes I can hold my hand on any section of my ducting.  After that, most sections are too hot to touch. The pipe that leads up and out the roof, I can hold my hand on that one for almost an hour, after about an hour of a rip roaring fire, then the chimney pipe gets too hot to touch.  I attribute it to the fire bricks reaching temperature.  I lit a fire yesterday and when I went to start a fire today almost 18 hours later, the bricks at the roof of the burn tunnel had just a touch a noticeable heat to them. 

I bet after a longer burn, your temps will come up a quite a bit.....and the smaller the diameter the wood, the greater the surface area, and the hotter it will burn.

!



Hi Eric,
  Hope the smoke is clearing. Sometimes you gotta make the mistakes...certainly my best teachers!

I let it run a solid hour before temping.  Barrel was too hot to touch, but everything (EVERYTHING) else was lukewarm.  Makes me a little concerned.  I have a 6" system and I believe your's is 8", but I can't imagine that should be a factor.  Does yours burn fast?  Still wondering if there is too much draft.

Exciting to have them running!
 
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Stacy, your temps seems low, but the heater is wet.

Is your's pulsating like this,

 

If yes, that's bad. 

Well, you have about 3.64m² of surface in the pipes,  that's a bit on the low side.  Because the bottom third of a round pipe doesn't heat up much.

One idea i just had.  If i remember well, you said you shortened the bench at the T's end.

I would try to make an armrest bell there.


Make a rectangular box, may be a foot, a foot and a half in width, the length of the bench's end. And sticking up 8 inches, from the bench's top.  That would add 0.8/1 m² depending on what you do exactly. 

You make a removable top to allow for cleaning.
 
Staci Kopcha
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thomas rubino wrote:Hi Stacie;  

IF you really have to much draft... and i'm not so sure of that yet.  Then Max's idea is a good one. Here's how a bell and plunger would work

Where your current exhaust pipe leaves the mass, instead of it connecting directly to your outside chimney you would build a brick box . your mass woulds vent into  that box(bell).  Meanwhile your chimney is then plumbed into the same box but with a section  or two of stove pipe would extend (the plunger)towards the bottom of the bell. Your rocket vents into the bell, the hottest air rises and the cooling air sinks where it gets drawn into the outgoing chimney. When he mentioned an adjustable plunger ,that is a sliding pipe (won't work with your set up) that starts out high in the bell to get the draw going and then is lowered down to maximize how much heat is staying inside.

I think you need a bunch more fires to decide that you have too much draft.

Your firewood needs to be much smaller to start with. When I mentioned free Pallets I was very serious,  a lot are hardwood ,all are free and they are very dry thin wood.  Rounds of any dia are just going to start harder.  Save them for now or split them down.

Your stove did super awesome for a first burning !!! Way better than I warned you about !  Way better than my first rocket did!  We are Proud of you and your accomplishment !  Don't stress this draft thing.  Learn how your stove lights. Dry that mass out.  Get smaller wood , take temp readings .  You GOT THIS !



You're the best, Thomas!! Loved the pic. :)
  I will have to draw out/make a visual so I can put my head around the plunger-bell thing.  Your description is a big help.  Something like a second manifold for the ducting exhaust and chimney pipe?  Could probably manage...but will cross my fingers to not need it.
  I tried splitting the wood today.  Hard with 2-3" diameters.   Oh lordy, though, do we have pallet wood- my husband has a fine collection! Some are broken down, but those I am not sure of Heat treated or chemical treated- is that okay?   I posted my reads from today and am a bit concerned.  Eric Hammond's roaring beast has its pipes smoldering while mine seem barely warm to touch.
I let it go for a solid hour before testing...should I wait longer? I will do some more fires and keep testing and posting.  Should I hold off on more cobbing  until I am sure of my system?  We have a run of sunny days (odd for Oct. in PNW), which I would love to take advantage of.

Thanks again!
 
Satamax Antone
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Stacy, here are examples of a plunger tube.

https://permies.com/t/69146/Bell-questions

https://permies.com/t/40/31382/Rocket-Stove-cast-riser#246601

It's pish easy to do. You get a barrel, exit from the mass at the bottom, on one side,  may be raise the tube inside 30cm. To make a stub. 

Then you divert the tube from the ceiling, with two elbows. Enter the top of the barrel, and go down to 20 or 10 cm from the bottom. furthest away from inlet pipe as you can.  And add a thick cob over the barrel, and plunger tube's entrance into the barrel.
 
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Satamax Antone wrote:Is your's pulsating like this,

 
If yes, that's bad.


As always, I hate to contradict you Max. A slow pulse like twice or 4 times a second is not good, I do agree with that. But in order to know what speed the pulse in the video was going I slowed it down at the time and calculated it as something like 40 times a second, much like a pulse jet engine. The Testo gas analiser confirmed it was a very clean burn while the fuel was racing through as nothing else. Together with absolutely top temperatures of the small drums as the result. As far as I know of, nobody has mimicked this behaviour until now so it might has been the result of a number of specific circumstances.

So I wouldn't regard this as a good example of a pulse like a steam engine, and I might stress again such a slow pulse is considered wrong behaviour of the heater.
 
Satamax Antone
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Hey Peter, no worries.

I must not have been awake yet!

Have you heard this one?



I'm pretty sure i know how it can be replicated. Well, kindof.

Stacy, the bad pulsating one, you can even see the flames coming back out.



 
Peter van den Berg
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Satamax Antone wrote:Hey Peter, no worries.
I must not have been awake yet! Have you heard this one? I'm pretty sure i know how it can be replicated. Well, kindof.


OK, the first one is what I meant with a rapid pulse. Hard to count but it seems to be something between 35 and 40 pulses a second. I didn't know about this one, although it's published nearly 3 years ago. I am all ears how it could be replicated, imagine one could run such a small thing with pellets and get this type of performance!
The second one is the slow pulse, the Testo won't be happy with this for sure.
 
Satamax Antone
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Well Peter. I don't understand all the aspects of this.

https://en.wikipedia.org/wiki/Valveless_pulsejet#Valveless_pulsejet_operation

But i think it's a matter of having a small air intake a bigger exhaust, and a burn chamber.

It has to do with static pressure waves, and helmoltz resonant frequencies and whatnot.

The batch box, or J tube, with it's feed chocked with wood could apply for this.

But making an extremely insulated firebox, with two pipes exiting. Could prove interesting. Even with a venturi at the entrance of the big tube.

BTW, did i ever show you this?

http://nyethermodynamics.com/nt6/index.html
 
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Staci Kopcha wrote:  Oh lordy, though, do we have pallet wood- my husband has a fine collection! Some are broken down, but those I am not sure of Heat treated or chemical treated- is that okay?



Don't use chemically treated pallets. Heat treated ones are OK.

We recently had a delivery of over 70, 10 feet long pallets that were used for transporting roofing sheets - they are heat treated only. I've saved the long lengths of planking for future construction work but the rest are providing lots of great kindling and 'rocket wood'.
 
thomas rubino
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Good Morning rocket scientist ! 

Give it time, my mass (bigger than yours) took 5-6 WEEKS before the far end of the mass warmed up . You put a lot of water in that cob and it has to go away. You've burned two times.  After 20 times it will be better after 200 times you won't have this problem at all.
KEEP BURNING... Every time you do it will get better and better.

Yes , use up your pallets , if they are too nasty pass them by.  A cordless skill saw or a small cordless chain saw make short work of pallets . Splitting small wood is a bugger.  3" and up gets easier.  Are you using the Tire bolted to a chopping block method?  It works , its what I do.

EDIT) Eric has an 8" batch box they burn much hotter than a 6" J .  He also has been building it quite awhile, so it has had more time to dry than yours. He has that huge tall beautiful chimney which, like a big straw pull that heat up and out.  
Your is swaying to the tune in a few weeks it will be rocking out !
RMH-rebuild_192.JPG
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Splitting wood down the easy way
 
thomas rubino
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Stacie;    In my humble opinion   that wave, sucking sound your hearing is your baby dragon yawning (i mean geez she was just born AND you just woke her up) wait till she roars ... you will be in awe !
Keep cobbing !
 
Staci Kopcha
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Thanks for all of the feedback!!!You guys are so awesome!

Clarification:  The sound/waves, that I heard was not a steady thing- just a few times.  Sounded like strong gust of wind wind, except instead of air being blown, it was a  suction of the fire down the burn tunnel.

Thomas reminds me that patience is not my strong point and problem solving/trouble shooting is a favored activity.
I will fire up my baby dragon again today, diet heavy in pallet wood.  And practice "wait and see".
Planning to have a family wood sorting/cutting party today. Woo hoo! Where is the forum on motivating kids? ;)

 
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  I am all ears how it could be replicated....



Peter, I am currently burning all the small odds and ends from this summers building projects before digging into my straight 'good wood' and am noticing that my J tube rocket is making the pulse jet more often when I load a lot of these small pieces in at once with many irregular air gaps down the feed tube. As in your video, when I jiggle the stack of wood in the feed tube, it too either increases, decreases or stops the pulsing altogether. Doesn't seem to happen (as much)  that I recall when there is lots of straight (laminar) flowing air gaps around the wood but moreso when there is turbulent air intake being feed to the fire below. I would say the rate mine pulses at is somewhere between the two comparison videos Satamax posted.

Stacy, here are examples of a plunger tube.

https://permies.com/t/69146/Bell-questions



Staci, One of links Satamax gave you to look at was his advice to me on bells and plunger tubes. I have since been using this system and am really liking it however, I agree with Thomas, your system is just waking up with lots of web cob to dry out which will affect its performance. Perhaps a good time to just let the rough cob dry out before finishing it all off.
I too started with pipes then migrated to pipes leading to a bell, then just got rid of the pipes all together and made it one bell. I am certainly not regretful of doing any of these modifications as they all have taught me so much of how hot gasses flow and am still learning.


Those IR temp guns don't work well on shiny surfaces like HVAC ducting.



I have put a piece of masking tape about 2"x2" in my pipe, flat spray paint, magic marker or even smear a little clay slip on the portion of pipe that I want to take IR thermometer readings on with much more accurate results.
 
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"I too started with pipes then migrated to pipes leading to a bell, then just got rid of the pipes all together and made it one bell. I am certainly not regretful of doing any of these modifications as they all have taught me so much of how hot gasses flow and am still learning."


Gerry. I'm trying to decide whether to build off the same plan as Staci or to use the bell. Given the issues, folk have with controlling the draw using pipes (and mitigating through adding or removing bends) how is the draw controlled using a bell? I have a lot of rubble and clay I was planning to use for the flue heat exchange but I can also get my hands on a thousand bricks if need be very easily. I'm in Australia and the flue is quite expensive compared to colder countries and Tees are a $100 a pop. How does a bell bench hold on to heat compared to a pipe heat bench, please?
Thanks
Dan
 
Staci Kopcha
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Hi,
  I fired it up again today and let it run for a solid two hours.  Getting a bit warmer, through the first duct- still cool at second.

Some things of note:

1) a HUGE win: I turned off our house  heater today (forced air, gas) as it was warm in the day and forgot to turn it back on in the evening, and YET the house temperature at 8 pm was 66 F ( I usually keep it set at 64 anyways, cheap) AND then IT WENT UP to 67-  ALL because of this charming heater in our playroom!!!  Speaks much for what it will do for our normally cold and drafty house this winter!!  I am thrilled!!

2) In pictures, you can see the cob drying nicely on areas around the barrel and on the manifold (light grey), in contrast to the dark grey of the bench.

3) Already warming our butts after a hard day of cutting, moving, stacking wood.

4) Rabbit and kid approved.
DSC_1087.JPG
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Satamax Antone
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Daniel Hatfield II wrote:


"I too started with pipes then migrated to pipes leading to a bell, then just got rid of the pipes all together and made it one bell. I am certainly not regretful of doing any of these modifications as they all have taught me so much of how hot gasses flow and am still learning."


Gerry. I'm trying to decide whether to build off the same plan as Staci or to use the bell. Given the issues, folk have with controlling the draw using pipes (and mitigating through adding or removing bends) how is the draw controlled using a bell? I have a lot of rubble and clay I was planning to use for the flue heat exchange but I can also get my hands on a thousand bricks if need be very easily. I'm in Australia and the flue is quite expensive compared to colder countries and Tees are a $100 a pop. How does a bell bench hold on to heat compared to a pipe heat bench, please?
Thanks
Dan



Daniel, there is another way.

Metal tanks!  You know, home heating fuel tanks, tractor fuel tanks. Whatever metal container.



See this. There's a tank used as a "barrel" . but it is more like a bell. Big volume. Then  there is a huger tank,  covered by normal brick, filled with concrete.

You Can make your mass with whatever stuff you want, when you use this system.  Stones, mud, engine blocks, anything pretty  much. You can even stuff mass inside, instead of out. As long as it doesn't wreck with heat.


A before And after pic, kindof. The "core" isn't the same on the before pic.

https://scontent-mrs1-1.xx.fbcdn.net/v/t31.0-8/fr/cp0/e15/q65/12030278_10201166055310900_1568102161558568907_o.jpg?_nc_cat=111&efg=eyJpIjoidCJ9&oh=9d7297ec0759532a77e0c2a9b7dbd2fa&oe=5C400923

https://scontent-mrs1-1.xx.fbcdn.net/v/t31.0-8/fr/cp0/e15/q65/12247888_10201230806489639_5997649765225692282_o.jpg?_nc_cat=111&efg=eyJpIjoidCJ9&oh=2a291b26f62a238d9e95513dacf70204&oe=5C46FD37

But the big tall tank is still behind the bricks.
 
Gerry Parent
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Daniel Hatfield II wrote:how is the draw controlled using a bell?


Hi Dan,   Thomas pointed out about the sliding plunger tube earlier however I found that without any insulation around the plunger tube once things warmed up a bit, the tube acted as a siphon and my exhaust temps started to skyrocket even though it was only about 1.5" from the floor of the bell. I really like his idea though as sometimes my cold starts could sure use a boost in particular when its at the fringe part of the season. I have gone with trial and error and found that sweet spot where its high enough off the floor of the bell to provide a good draw but not so high that I loose too much heat up the chimney.
There are formulas for bell sizing also you could look up on this forum if your interested.


How does a bell bench hold on to heat compared to a pipe heat bench, please?
Thanks
Dan 


Well, a pipe system will heat the area right above it faster than along its edges making hot spots or hot lines along the mass. The further you get towards the exhaust the cooler these lines will become. A bell tends to heat more evenly along the top surface as the heat is stratified over a much broader area. Of course a bell doesn't have to be a bench either depending on your footprint available and purpose for it.
I've also seen some designs made with horizontal brick passageways so metal piping is also eliminated.

Daniel Hatfield II wrote: I'm in Australia and the flue is quite expensive compared to colder countries and Tees are a $100 a pop.


We have a resale store called Habitat for Humanity that sells used metal piping for a lot cheaper. Perhaps you have something similar depending upon your time frame.
In a pinch, I've made some elbows from tin coffee cans. They are exactly the right size too!
The original rocket mass heaters were often about scrounging for parts and built very cheaply with innovation at the forefront of design.

Most of the inspiration for my change came off the experience of others. One of them was from Donkey over at proboards:

http://donkey32.proboards.com/thread/1915/evaluating-retrofitting-rocket-bench-video

Another from dragonheaters which gave a clear definition of how and why bells operate more efficiently:

http://blog.dragonheaters.com/wood-heat-storage-flues-vs-bells/

One more from Peter van den Berg:

http://batchrocket.eu/en/building#belltheory

Staci Kopcha wrote:2) In pictures, you can see the cob drying nicely on areas around the barrel and on the manifold (light grey), in contrast to the dark grey of the bench.


Staci,  Its a small thing but something that I have began to pay attention to (after taking my stove apart again and again) is why certain areas dry faster than others. Is it because there is less insulation there? less rock and more cob ? a hot spot that could burn a kiddo or bunny rabbit? or even a potential weak spot? Just another part of the process which can teach me more about what is happening and how I can improve on it if needed.
Looks like your boy is a happy camper there!


 
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Staci Kopcha wrote:
Some things of note:

1) a HUGE win: I turned off our house  heater today (forced air, gas) as it was warm in the day and forgot to turn it back on in the evening, and YET the house temperature at 8 pm was 66 F ( I usually keep it set at 64 anyways, cheap) AND then IT WENT UP to 67-  ALL because of this charming heater in our playroom!!!  Speaks much for what it will do for our normally cold and drafty house this winter!!  I am thrilled!!



One thing that old forced air furnace may be able to do for you, is circulate the heat to parts of the house, if you Find the heat is concentrated in the room where the mass heater is and do you want warm air in the rest of the house.

  To do this, it will have to have a fan only circulation mode, for which there may be a switch on top of their portion of it that houses the blower fan.

  Often the documentation for these units can be found online by the manufacturer and model number.

  You may find this idea helpful, or totally useless/unnecessary, based on your system’s (likely significantly improved) heating performance once fully dry.

If you find yourself getting “baked out” in the room with the stove and mass, and too cold in other parts of the house, the use of your circulation fan may help, depending on how things are laid out.
 
 
Staci Kopcha
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Update:  I think it is okay on draft!!!  I can leave all of the plunger/bell/whatnot to you more adept folk.  (huge sigh of relief!)

Daniel Hatfield:  I think I jumped to conclusions and it is turning out to be a good system for our little house.  What type of space are you needing to heat?

Matthew Goheen: great suggestion for the furnace fan, thank you!.  Unfortunately, the fan control option was never hooked up to our in house thermostat control (furnace is in basement). I am sure it is fixable, but after 10 years here, it is still so. 
 
Dan Hatfield Ii
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"Daniel Hatfield:  I think I jumped to conclusions and it is turning out to be a good system for our little house.  What type of space are you needing to heat?"

430 square feet. it will be straight on a wall (not L shaped) because of the layout.
This is in my studio/office. if I make it look nice I get to build one in our living room.
I'm worried about the draft now as it will effectively be shorter without all those turns.
I want to keep it as simple as possible for my first indoor build.



 
Staci Kopcha
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Daniel Hatfield II wrote:

"Daniel Hatfield:  I think I jumped to conclusions and it is turning out to be a good system for our little house.  What type of space are you needing to heat?"

430 square feet. it will be straight on a wall (not L shaped) because of the layout.
This is in my studio/office. if I make it look nice I get to build one in our living room.
I'm worried about the draft now as it will effectively be shorter without all those turns.
I want to keep it as simple as possible for my first indoor build.



Ernie and Erica have a nice little one, no "L" .  (link below)  I haven't seen the plans, but it is a single short bench on an 8" system. Curious about the layout.  Anyways, it may be another option and save you the cost of some of the ducting that was $$/hard to get in your area.
AND it looks "nice:, so it may pave way to the living room.

https://permies.com/t/40984/Rocket-Mass-Heater-Plans-Cabin#319710
 
Dan Hatfield Ii
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Staci Kopcha wrote:

Daniel Hatfield II wrote:

"Daniel Hatfield:  I think I jumped to conclusions and it is turning out to be a good system for our little house.  What type of space are you needing to heat?"

430 square feet. it will be straight on a wall (not L shaped) because of the layout.
This is in my studio/office. if I make it look nice I get to build one in our living room.
I'm worried about the draft now as it will effectively be shorter without all those turns.
I want to keep it as simple as possible for my first indoor build.



Ernie and Erica have a nice little one, no "L" .  (link below)  I haven't seen the plans, but it is a single short bench on an 8" system. Curious about the layout.  Anyways, it may be another option and save you the cost of some of the ducting that was $$/hard to get in your area.
AND it looks "nice:, so it may pave way to the living room.




https://permies.com/t/40984/Rocket-Mass-Heater-Plans-Cabin#319710




Thanks staci,

I have supported Erica and Ernie's stuff for years and have bought everything (almost) they have put out and filed it.
My layout would be very similar to this one but 6". I already have the 6" exit chimney in place so I don't want to change that out for 8".
I will need to move it (rather than have angled pipe going up) but our roof is metal so it's fairly easy to relocate.

I have the plans for (and am going to use) Mat Walkers super hot J made from duraboard.
https://walkerstoves.com/super-hot-ceramic-fiber-cores.html

I am an eternal entrepreneur so I'm (always) looking to figure out an easy way to build a core, manifold and bell in one easy (ish) to ship package. I think I have it.
I just need to run it for a year

 
Staci Kopcha
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I have the plans for (and am going to use) Mat Walkers super hot J made from duraboard.
https://walkerstoves.com/super-hot-ceramic-fiber-cores.html

I am an eternal entrepreneur so I'm (always) looking to figure out an easy way to build a core, manifold and bell in one easy (ish) to ship package. I think I have it.
I just need to run it for a year



I was unfamiliar with the duraboard/Walkertoves- pretty neat!  I hope that you post your build, I will be interested in seeing it.  Future upgrades
 
Staci Kopcha
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Hi, a few questions/concerns, if you please.

General: (for concept understanding)

1) Is  a "batch system" a system that has a horizontal fuel feed, unlike the vertical of the "J" system?  (if so, is there a benefit of one vs the other?)
2)  in a "bell system", "bell" is basically a manifold? You make manifold like things to eliminate ducting? Do you get to eliminate cob as well?? ;)


3) for a J-tube burn, once the kindling and small pieces are going steady, do you just fill the entire box and let it go?  Or, do you keep adding as the front line of wood falls?

My build:


  Been doing a burn every day.  Seems to be hit/miss for an easy start. Still perfecting technique. A day on which I feel I have perfected it, is followed by a taxing ignition.

1) I am concerned still by the cool to touch temp. of the second run pipe.  I was adding another layer of cob/rock and noticed that this pipe ended up being slightly higher ( yet level) than the first run pipe (due to messing with it at the time of stove pipe attachment), would this create some uneven gradient to cause resistance?  OR maybe it just needs to finish drying?  (I had a fan on it today).

2) today, the burn resulted in a very smoky chimney exhaust. Very stinky outside.  This is something I REALLY (save the earth, clean burn, and I get a headache) want to avoid, so I hope to better understand why this would be so I can do my best to avoid it.  I can't think of how I did anything different from my previous burns, except perhaps wood lottery was different.  (I have such a varied mix).  It definitely was burning slower toward the end today and the last bit of log just took its slow sweet stinky time .  I believe green wood can give smoke, but I am fairly confident in my lack of green wood, but of course could be mistaken.  Anyways, any thoughts on getting the cleanest, hottest  burn possible, would be appreciated!

3) Is there an ideal length of wood?  My husband cut most (miter saw) about 13", so they seem to hit and inch or so above the burn tunnel entrance, but set pretty low in.  We also have lots of short /end pieces- can those go in?

Thanks!!
 
Satamax Antone
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Stacy, a bit of history.  First of all, Ianto Evans invented (or rediscovered) the L tube, for cooking. It was supposedly inspired by the bengali firepit.  I don't know exactly when he met Leslie Jackson, with who he wrote the book with.


Then came the J tube, as he thought self feeding was cleverer. May be also inspired by the fumivore de Dalesme. See bellow.  I think this is about that time when the tube and cob mass heater has been "invented".

Few years back Donkey and Canyon (Kirk Mobert and Lasse Holmes) Were playing with mud, and made the first "Batch" It's more or less a L tube, into which you can feed a batch of wood, instead of sticks, to keep the fire going for longer time, without tending. As the J tube, in the opinion of some, is tedious to tend.  (myself included)

http://donkey32.proboards.com/thread/511/adventures-horizontal-feed

Peter Van Den Berg jumped in, and sorted all the dementia and proportia . Work which is still in progress. With idiots like me, trying to develop other iterations of it.


As for your fire tending, you get it going, then fill the feed with sticks log'ettes.  Then you listen to the beast, and re arrange as needed, when you're at ember stage, you let the embers go down a bit, and re fill with another load. Until your mass and room are at the right temp.

Don't worry about your tube being cold. Drying the mass can take several weeks/ months, and it takes lots of energy from the gases.

fumivore-de-dalesme.jpg
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John Harrison
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Hi Staci.

Peters excellent resource site on Batch Box Rockets explains what a'bell' is in easy to understand terms. Batch Box Information

The general consensus appears to be that a 6" Batch Box is more powerful than a 6" J Tube.

I have a 6" J tube and a 5" Batch Box and they smoke if I use 'less than dry' wood or if I cram too much fuel into the feed tube/firebox.
 
Peter van den Berg
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Specifically for how bell systems are done, see http://batchrocket.eu/en/building#belltheory
 
Dan Hatfield Ii
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Staci Kopcha wrote:




I have the plans for (and am going to use) Mat Walkers super hot J made from duraboard.
https://walkerstoves.com/super-hot-ceramic-fiber-cores.html

I am an eternal entrepreneur so I'm (always) looking to figure out an easy way to build a core, manifold and bell in one easy (ish) to ship package. I think I have it.
I just need to run it for a year



I was unfamiliar with the duraboard/Walkertoves- pretty neat!  I hope that you post your build, I will be interested in seeing it.  Future upgrades


Hi staci,
I will do and I will use this thread to report if that’s ok. I’ll be building in February once our heat starts to drop.
You will be a seasoned expert by then so you can help me I hope.
Thanks
Dan
 
Staci Kopcha
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Satamax Antone wrote:Stacy, a bit of history. 



Great synopsis!  I appreciate it.
 
Dan Hatfield Ii
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Peter van den Berg wrote:Specifically for how bell systems are done, see http://batchrocket.eu/en/building#belltheory



Thanks peter.
Do you have any resources (sizing or maths) in bell bench building (stratification chambers).
I’m considering going that route to save money and time on flue fittings.
hartelijk bedankt
 
Staci Kopcha
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Hi staci,
I will do and I will use this thread to report if that’s ok. I’ll be building in February once our heat starts to drop.
You will be a seasoned expert by then so you can help me I hope.
Thanks
Dan

Hi Dan,
  I will look forward to it!
Staci
 
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Dan Hatfield Ii wrote:Do you have any resources (sizing or maths) in bell bench building (stratification chambers).
I’m considering going that route to save money and time on flue fittings.


A bell bench isn't any different as compared to an upright bell. Please use the tables given on the website. In case the bench is built as a second bell deduct 15% of the total cross section area of the system.
 
Staci Kopcha
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Hi,
Still firing and working on cob here.  Endless cob.
Start ups are going much better! Burning cleaner!
  Question on thickness of cob:

     I know top of manifold is about 5 and 6" above pipes, but:

      1: the rest of the manifold?
      2: fuel feed?
      3: res of pipes: is it 6" all the way?

Thank you!
DSC_1107.JPG
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Gerry Parent
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Staci Kopcha wrote:Hi,
Still firing and working on cob here.  Endless cob.
Start ups are going much better! Burning cleaner!
  Question on thickness of cob:

     I know top of manifold is about 5 and 6" above pipes, but:

      1: the rest of the manifold?
      2: fuel feed?
      3: res of pipes: is it 6" all the way?

Thank you!



Something that I had said earlier:

Well, a pipe system will heat the area right above it faster than along its edges making hot spots or hot lines along the mass. The further you get towards the exhaust the cooler these lines will become.



In other words, the manifold and first section of pipe is going to get the hottest so either thicker mass or more rock (density) in these areas to help slow and retain this extra heat. The rest can be either tapering thinner or less dense mass to allow more heat to get to the top of the mass and have the heat more evenly distributed across the bench. It also depends on how long you would like to burn on average so that you can actually feel the heat in the bench and also how long afterwards you would like to still feel it. The recommended heat:thickness transfer ratio that I have heard is 1 hour for every inch of thickness - give or take on whether its cob or rock. However since each stove is unique, trial and error may be your best approach. You could decide on a thickness of lets say 3" but leave it rough so that if you add more on later to all of it or just certain spots.
 
Staci Kopcha
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More cob woes.
I regret to admit that I have been mixing cob in the way I follow my cooking recipes. ("loosely based").

My initial mix was mostly sand and clay, with a small bit of dirt. (bottom layers of bench).
I was going through sand and clay faster than I wanted AND the sand was cutting/hurting my feet when I stomped (I have worn boots as well, but they are cumbersome) , SO I upped the dirt in my mix. (dirt is free, sand and clay I have to buy)
I did a few test bricks and baked in the oven and did fine so I proceeded with my 1/2 dirt, 1/4 sand. 1/4 clay mix.
Now on the bench, that layer is lined with cracks.

  *Should I UN-DO these layers?

  I have been trying to search for local clay source, and as Thomas Rubino suggested, even knocked on the door to the construction trailer at  site of the future upgraded Salmon Hatchery.. said I was welcome to the dirt, but the stuff they were digging was mostly old fill. No clay.  (I was hoping they were dredging the creek).


Thank you.
DSC_1113.JPG
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DSC_1116.JPG
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Satamax Antone
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I have always heard, if it cracks, there is too much clay.

Have you tested your "dirt" for clay?
 
I got this tall by not having enough crisco in my diet as a kid. This ad looks like it had plenty of shortening:
Food Forest Card Game - Game Forum
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