Peaceful Valley*
Permies likes wood burning stoves and the farmer likes Could not wait, built my first rocket stove before reading the book. Let me know what ya think. permies
  Search | Permaculture Wiki | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


(the sound is wonky for the first 20 seconds)

daily-ish email

micro heaters

rocket mass heater

wofati

permies » forums » energy » wood burning stoves
Bookmark "Could not wait, built my first rocket stove before reading the book. Let me know what ya think." Watch "Could not wait, built my first rocket stove before reading the book. Let me know what ya think." New topic
Author

Could not wait, built my first rocket stove before reading the book. Let me know what ya think.

Jared Mevissen


Joined: Feb 24, 2012
Posts: 4
So I have not read the book yet, basically just went from lots of diff forum posts and vids and got the gist of it. I wanted to try it out before it got hot "which I accomplished" got this finished and tested outdoors about a week before the snow was gone. I still have not tested it in my workshop but I have to do some leveling etc in there before I can install it so will not be able to do that until next fall anyhow, but at least I know it "works".

Anyhow any comments or suggestions would be appreciated I plan to read the book this summer, and make another one like this but smaller for heating a deer blind I have.

Here is a vid I made of building it and testing it.
http://youtu.be/aHF1edk5d0c



I am sure I may have screwed up a few things, especially the heat riser. I want to read up and redo that because I don't think it is void of voids. But it does seem to work so I dunno, maybe its ok.

Also sorry about the vids being so long, I wanted to document the main stuff so that I could easily look back and see how I did it later on etc.
Len Ovens


Joined: Aug 26, 2010
Posts: 1238
Location: Vancouver Island
    
  14
Jared Mevissen wrote:So I have not read the book yet, basically just went from lots of diff forum posts and vids and got the gist of it. I wanted to try it out before it got hot "which I accomplished" got this finished and tested outdoors about a week before the snow was gone. I still have not tested it in my workshop but I have to do some leveling etc in there before I can install it so will not be able to do that until next fall anyhow, but at least I know it "works".
...
I am sure I may have screwed up a few things, especially the heat riser. I want to read up and redo that because I don't think it is void of voids. But it does seem to work so I dunno, maybe its ok.


Seems a bit cool, my top gets 200-250C But then I did have a bigger fire and was into about 2 hours of burn. From what I saw your riser looks ok. I can't tell what your head space is from the vid. Should be just under 2inchs. The gas close to the walls doesn't move as fast as the gas in the center. The temp measured on the barrel walls and flue pipe are lower than the temp in the center of the flue gas stream... That is why there is still heat to extract with a bench.

Not sure what to make of the feed. I thought of doing it that way too, but decided to use an upside down T instead. It gives me a "clean out" too.
Jared Mevissen


Joined: Feb 24, 2012
Posts: 4
Len Ovens wrote:
Jared Mevissen wrote:So I have not read the book yet, basically just went from lots of diff forum posts and vids and got the gist of it. I wanted to try it out before it got hot "which I accomplished" got this finished and tested outdoors about a week before the snow was gone. I still have not tested it in my workshop but I have to do some leveling etc in there before I can install it so will not be able to do that until next fall anyhow, but at least I know it "works".
...
I am sure I may have screwed up a few things, especially the heat riser. I want to read up and redo that because I don't think it is void of voids. But it does seem to work so I dunno, maybe its ok.


Seems a bit cool, my top gets 200-250C But then I did have a bigger fire and was into about 2 hours of burn. From what I saw your riser looks ok. I can't tell what your head space is from the vid. Should be just under 2inchs. The gas close to the walls doesn't move as fast as the gas in the center. The temp measured on the barrel walls and flue pipe are lower than the temp in the center of the flue gas stream... That is why there is still heat to extract with a bench.

Not sure what to make of the feed. I thought of doing it that way too, but decided to use an upside down T instead. It gives me a "clean out" too.


I never even really thought about using a T, in retrospect it would be nice however clean out does not appear to be a problem it might be if I was running it for an extended burn "hours at a time" and the buildup in the burn/feed area became to much to the point that it would restrict airflow. But I kinda doubt it and I hope not to have to run it that much. This one or the one I build after this one will be for heating a workshop that is only used once in a while. Another thing with a T I would have to have it come out the side in this design unless I planned on having this up off the floor which I am currently not. "Actually contemplating setting it in the earth floor and doing the floor as the mass assuming I would have to insulate under the mass if I did that however"

As far as the head space goes I never even measured, I did read a part in the book that said that as long as it was under 12" it was fine..... ok so I just went and re-read that part in the book, I must have misread it and or looked at the diagram wrong so I am assuming my heat riser is not high enough but will have to measure.

So at this point my main concerns are the riser, and possibly the exhaust exit on the back of the barrel in a standard rmh this area seems to be wider than 6" however the gasses are dropping down, so by going straight out the back of the barrel with the 6" opening is this big enough?

So I just looked up the Height of a 30 gallon barrel I get a inside Height of 27.5 so being that my riser is made of 2' stove pipe "I believe its 2' have to measure to be sure that would mean I have a space of 3.5" + or - a bit considering now I have the gasket under the barrel and just my barrel may be diff than the one I Have looked up. So it says here in the book it should be 2-3" for an 8" system and 1 1/2 to 2" for a 6" so I am probably off by a ways so by being more than the recommended distance how does that affect it? I mean in my tests it seemed to work especially my last test which would be the furthest away since I added the gasket under the barrel. I could hear the system "running" from 60 feet away

Oh ya and in my newest vid I could not measure the heat on the top of the barrel my laser temp sensor stops at around 320f or so. So its possibly it got up to the same temps as yours I just don't know, don't have anything to measure that with currently. Also my longest burn has maybe been half an hour of decent fire probably not even that long.
Len Ovens


Joined: Aug 26, 2010
Posts: 1238
Location: Vancouver Island
    
  14
Jared Mevissen wrote:

I never even really thought about using a T, in retrospect it would be nice however clean out does not appear to be a problem it might be if I was running it for an extended burn "hours at a time" and the buildup in the burn/feed area became to much to the point that it would restrict airflow. But I kinda doubt it and I hope not to have to run it that much. This one or the one I build after this one will be for heating a workshop that is only used once in a while. Another thing with a T I would have to have it come out the side in this design unless I planned on having this up off the floor which I am currently not. "Actually contemplating setting it in the earth floor and doing the floor as the mass assuming I would have to insulate under the mass if I did that however"

If you didn't want to put the T upside down, the other idea is to put it sideways with the part sticking down blocked off. This would give you an ash pit and somthing to hold your fuel upright without sliding.


As far as the head space goes I never even measured, I did read a part in the book that said that as long as it was under 12" it was fine..... ok so I just went and re-read that part in the book, I must have misread it and or looked at the diagram wrong so I am assuming my heat riser is not high enough but will have to measure.


The head space should have the same CSA as the riser or a bit more. A 6inch riser has a csa of about 28sqin. So the head space might be:

H x (pi) x 6 = 28

28/(3.14x6) = H = 1.4854 inches or about 1.5 inch

The normal (for 6 inch) is about 1.75 (.25 inch extra) to allow for ash build up, gas direction change, etc.


So at this point my main concerns are the riser, and possibly the exhaust exit on the back of the barrel in a standard rmh this area seems to be wider than 6" however the gasses are dropping down, so by going straight out the back of the barrel with the 6" opening is this big enough?


In my (not so humble) opinion, your way (and mine BTW) is better. In a normal RMH the entrance to the exhaust is only from above and the space from the pipe to the riser is quite small (about 4 inches). So the other direction had to be 12 inches or so to get the riser CSA. With the way we have done, the gas has access to the top and sides at least, about 3/4 of the circumference of the exhaust. So:

6 x 3/4 x 3.14 = 14.137

so all you need is at least 2 inches between your exhaust and the outside of your riser for the right CSA. I expect it is already more than that....

(radius of barrel) minus (radius of outside of riser) will tell what this is.


So I just looked up the Height of a 30 gallon barrel I get a inside Height of 27.5 so being that my riser is made of 2' stove pipe "I believe its 2' have to measure to be sure that would mean I have a space of 3.5" + or - a bit considering now I have the gasket under the barrel and just my barrel may be diff than the one I Have looked up. So it says here in the book it should be 2-3" for an 8" system and 1 1/2 to 2" for a 6" so I am probably off by a ways so by being more than the recommended distance how does that affect it? I mean in my tests it seemed to work especially my last test which would be the furthest away since I added the gasket under the barrel. I could hear the system "running" from 60 feet away


From what I have heard, that is not too bad. The rocket will still work but the hot spots will move down a bit and maybe spread out. The only way to tell if it will affect the rocketing is to add a bench and try... that is it is outside of my experience. Ernie might know.


Oh ya and in my newest vid I could not measure the heat on the top of the barrel my laser temp sensor stops at around 320f or so. So its possibly it got up to the same temps as yours I just don't know, don't have anything to measure that with currently. Also my longest burn has maybe been half an hour of decent fire probably not even that long.


Sounds good. even if it is a bit less, that may be because of the extra headspace.... and if it works that way... so what...
 
 
subject: Could not wait, built my first rocket stove before reading the book. Let me know what ya think.
 
Similar Threads
tree bog vs. dry outhouse
Nice to Meet you Mike!
RMH Mass heat absorption / insulation problem :(
Recycling animal and human dung for sustainable farming
concerns with using cardboard/newspaper as a mulch
cast iron skillet 49er

more from paul wheaton's glorious empire of web junk: cast iron skillet diatomaceous earth sepp holzer raised garden beds raising chickens lawn care flea control missoula electric heaters permaculture videos permaculture books