Hello. I have built a 6 inch rocket mass heater.
I will try to include some pics and a vid a for you.
The entire thing is sitting on 8 inch concrete blocks with 2' x 3' concrete pads. Burn chamber is fire brick surrounded by 6 inches of clay / perelite.
mass is mostly concrete pavers picked up from the dump for free surrounded by clay / sand
riser made out of ducting 6 inch inner - 12 inch outer clay / perelite insulate - barrel is 13.5 across.
started out with 1 brick width for barrel exit exhaust - found poor draft - so raised it up 2 brick widths - works better.
Pulled the barrel off - well - knocked barrel off - installing dry wall and heat shield - inner riser just covered with black flakes - creosote ?
Wiped it all down, put in about 1/2 inch of cob around bottom of inner riser - reinstalled barrel and layered poop plaster all around the base - for a good seal.
Drawing better now.
How hot should the outer barrel get ? After 30 - 45 min. I am averaging about 700 - 800 F. clean out at manifold is 250 F. Still waiting for mass to dry.

Good enough ?

More info if ya need it.

Thanks.

Edit : just noticed these are old pictures, will post newer pictures when I can.

Dave; 800 F sounds about right, my 8" gets 1000-1100 on barrel top. expect more as the mass gets dry.

Dave Lot : Temperature sounds about right ! Most of use are proud of the House Dragon that lies in our RMH, From the picture you appear to have a SPACE ALIEN
living in yours ! I can not tell from the picture if your barrel has been oiled or you still have the original coat of paint on it. Or is that a High temp BBQ or engine
block paint ! Generally we try to remove, encourage the removal of the paint before firing ! For the Good of the Craft ! Big AL

Here is an updated pic of the "Alien"

Still have some work to do on it. I had a guy come in to look at W.E.T.T. certifiying my stove (for insurance purposes), he says it looks good, but he wants to make sure his butt is covered. . . will let you know what happens there. . .

Second picture is the wood I burn in a bit over 2 hours.

The paint on the barrel - came with the barrel . . I was fully expecting to - have too sand blast the barrel - but, I have had it up too 850 F - on the SIDE of the barrel, with no odd smells or smoking . . so I guess it can stay as is ? ? ?

The cool thing is, that I have a video on my phone with a "guy" saying that you cannot build a rocket entirely out of steel - since it's so hot - but more importantly , he goes on too list the burning temps off materials in the smoke . .

auto ignite wood - 400-500 F
carbon - 800 F
hydrogen 1064 F
carbon monoxide 1120 F
1200 F minimum . . to burn everything . .

Fun fact, I dropped in an aluminum pop can, and within a minute, it was gone . . melted away into the ashes of the stove. . . Aluminum melts at 1220 F . . guess I am burning everything !

After a 3 hour burn, the chimeny temp was 130 F.

I have a piece of copper tubing at the back of the fire chamber . . will have too see if I can melt that ! (1983 F ).

Is there any way to add a video directly to my post ? I don't do the utube thing . ..

Well guys, I put a 3/4 inch copper tube in the back of the burn chamber, just too see what would happen.

Going by the pictures, it would seem that the inside of this stove gets up to at least hot enough to melt copper tubing (1,983 F) in spots.

Well, I have been trying to find someone to come over and W.E.T.T. certify my RMH . . I had one person come over and have a look at it. I gave him a call today, and he seems too think that this unit falls under the building code ( ). I told him, that it was a wood burning stove ( I should have said it's kinda like a masonary heater ) ... so as it stands right now, he is waiting for a return call - from the guy who W.E.T.T. certified him - to see how he should do this "thing" . .

Will keep you updated as I progress thru the liscensing of "the beast".

Here is a few more pics of the building process . . being able to only post 3 pics kinda slows things down a bit. . .

Oh, while I'm logged in, what is the best way to increase the chimney temp ? If I clay/perlite more of the barrel, will that bring up the exit temp - or will it just warm up the mass more ? My digital thermom - aimed at the pipe just before it goes out the wall, is reading about 120 F - would like to get more moisture outside - via steam . .

Thanks.

Dave Lot : Due to the nature of the unit you are using and a little physics You are actually very close to the number you want !

Your Thermometer can only read a surface temperature i.e. the piping and not the hottest gas flow which is in the very center
of the pipe so you probably are at 150ºF, maybe a little higher !

Ask to borrow a Kitchen probe for measuring liquid temps and watch the readings during your next fire, you can probably sneak
it in at the final clean out at your vertical chimney, though you may have to tape the clean out cap inlace to keep a tight seal !

Hope this helps and is timely ! For the Good of the Craft ! Big AL

Thank you for the answer on the final temp. I have lots of steam and condensation coming out the top of the chimney, so I guess as long as the water isn't flowing out of the side of the mass, I won't worry about it much.

Here is what I have learned so far. . . Trying to start a rocket when the entire thing is around 0 degrees is really interesting. For those of you who have tried to start a really cold rocket, you know all about smoke back - poor draft - you know, until it warms up, it don't work very good. .. here is an idea I came up with, and it works GREAT ! Turn on the light, wait - maybe 2 minutes - ya get lots of draft with no smoke back. Once the chimney starts feeling the least bit warmed up, I turn it off.

Hope this helps someone !

I can only post 3 pics at a time, so here is the next batch.

Someone asked about burning the paint of my barrel, and if you have a look at the pics, you can see the bare steel around the hottest part of the barrel, turns out, that where ever the barrel is really hot, the paint is powdering up and dropping off. By taking a wet clean X, and wiping around the barrel, this is what I found . . see pic. - no smell - no smoke - nothing.

Also, now that I have HEAT in the work shop, I moved all the ingredients inside before it froze, so I can finish off the final coat . . see pics
I mixed up :

3 parts horse manure
1 part clay
5 cups water + 1 cup flour
1/2 cup powdered milk with enough water to make runny liquid

The part right around the barrel, has some sand mixed in - with no flour or milk - and every time you rub it with your hand, it gets gritty. This mixture does not do that. As this layer dries out, I use my hand to tamp it smooth. So far, it looks great ! Once this part is totally dry, I will be moving all the barrels of sand and clay over to that side and finishing the rest. . . in the middle of winter !

Oh, outside temp is around 0 too -5 . . . a 2 hour burn will keep a 14 x 16 foot shed warm overnight drops to around 14 C and heats up too around 20 C - I'm happy, since you go outside and it's COLD.

Is there any way to put the pictures in the right spot in the post ? Or do they always have to be at the end of the post ?

Looking good.

How hard did your last cob coat turn out?

Been looking for a good hard mix for my final coat.

Dan Dronberger wrote:
How hard did your last cob coat turn out?
Been looking for a good hard mix for my final coat.

The final coat turned out pretty good, not very much dust, and very hard and durable... I dropped a 5.5 lb brick from 24 inches, and it hit corner first - left a 1/4 inch dent in the surface, but no cracks. I would be happy too cover this "thing" with a blanket, and sleep on it now .. . if I had too...

Update for you guys.
I took the advice of the pro's , and had my spare barrel sand blasted. When I pulled apart the stove, I am happy too report, that it is no longer all black and sooty in there, but a nice fine white ash . . it works ! first picture
I then replaced the old barrel with the clean barrel . . . second picture
Then I fired it up too 800 or so F, and it all turned a nice gun metal grey .... third picture.

Next, I was not happy with the amount of smoke back I was getting, so I added another layer of fire brick too the top of the burn chamber making it deeper. first pic.
It helped alot, now I can burn longer pieces of wood, and still have the bit of stray smoke stay in the chamber. first pic.
In the workshop that I have this "thing" installed in, the air gets a bit stuffy, so I installed a backwards bathroom fan - in hopes of getting more fresh air in for me when I am working (second pic). . . the by product of this, is that, since the shop is so well insulated and air sealed, the ONLY place for the air to get out is . . you guessed it - right out the rocket stove - TURBO ROCKET ! (third pic) - not a bad temp for the side of the barrel - on a 6 inch system.
Now I get fresh air, and the stove stays nice and hot to heat keep it warm. While it was around 0 degrees outside, I still had the shed up to 80 degrees and had too open the door !

I'm happy with it.

Add a ceiling fan too the 12 foot ceiling, with over night temps around 23 F and the shop only dropped from 80 degrees down too 70 degree F.

Oh ya, I can work with that.

Looks like a real clean build. I am wondering about the two rods sticking up to the right of the firebox, please do tell.
Scott

Scott Davidson wrote:Looks like a real clean build. I am wondering about the two rods sticking up to the right of the firebox, please do tell.
Scott

Gotta have somewhere to put your fire pokers - don't ya ?

The building inspector wants me too build in a timmies - coffee cup holder - into the mass - just at the bottom of the barrel - cup warmer . . may try that next ..

I realized that I do not have any pics of the construction of the burn tunnel area. . . so here goes. .

Pic 1 - riser parts
Pic 2 - 6 inch bed of perelite and clay
Pic 3 - burn tunnel started . . .

Next, layered on a layer of fire clay too seal any cracks in the burn chamber opening. . . pic 1
Built up the brick around the burn chamber too the 6 inch level . . . pic 2
Then filled in with clay perelit, topping off with layer of clay-with a bit of sifted sand in it. . . pic 3

By using cob, and small pieces of broken concrete, I built the manifold. . pic 1 and 2.

Hey Dave, thanks for all the pics!

I really like your heat lamp trick, by the way.

I don't know if you saw the paint removal trick with clay slip and newspaper wrapped around your barrel (Ernie and Erica do it often) but your barrel is definitely odd in its lack of paint loss. Where'd you get the barrel? It looks pretty thick.

Anyway, that looks like it was a fun build!

Dave Lot wrote:Is there any way to put the pictures in the right spot in the post ? Or do they always have to be at the end of the post ?

Yes, just click to place the cursor where you want the picture to be. Preferably one line below the description and with a couple lines after the picture, before the next paragraph.

David Eaks wrote:

Dave Lot wrote:Is there any way to put the pictures in the right spot in the post ? Or do they always have to be at the end of the post ?

Yes, just click to place the cursor where you want the picture to be. Preferably one line below the description and with a couple lines after the picture, before the next paragraph.

Thank you ! Some of the forums I have been on have a thread explaining the different ways too "how too" do things . . . like posting pictures . .. have not been able to find it on here yet . .

I will give it a try next time I post pics.

I picked up those 2 barrels from the scrap yard, 5 dollars each . . . have no idea where they came from or what was in em....

bit of an update for you guys.... I would like to be able too do something with all the heat this thing makes, so too that end, I have wrapped the barrel in 3/4 inch copper tube, and started to heat water with it. . . now - a quick warning to everyone who have not seen myth busters . . pressurized water goes BOOM !!

See picture. . . It's not going where I want it I put the mouse where I wanted the picture, and nothing !

That was the safety warning . . Now for the fun parts. . . by hooking up a grundfos pump on low speed, and having the water going into a 5 gallon pail, I have it figured out that I can produce around 4,000 btu's an hour . .. about 1/3 of the energy I need too heat my house - on the COLDEST days of the year - my heat pump is a 36,000 btu unit, and when it is -20 outside (coldest so far) it runs for 20 minutes every hour . . hence the 12,000 btu target . . .

first try . . see picture - it's not going where I want it !

The first problem, was too hook up a drain back system, so if the power fails, no water is in the pipe overheating . . . this setup drains back BEAUTIFULLY ! . . the next problem is too get the heat output up high enough too heat the house . .

second try . .see picture ... it's not going where I want it

The solar controller runs the pumps automaticaly, while the small radiator keeps the temperature down so I don't accidently melt the pail while I test run the system . . even with the radiator running, the water temperature still rises, just not that fast . .

Next step is too add a 1/2 inch coil on the top of the stove, and have it soak up somemore btu's to try to get up too the target output ...

60 degrees too 125 degrees in about 30 min ? - not fast enough !The nice thing about having 4 gallons of hot water in the work shop - it stays warmer overnight . .

I had someone on another forum tell me that you cannot get any more btu - out of a lb of wood - then what is already there - which he quoted as being around 6,000 btu per pound of wood - which works out really good for me, since a 10 lb hardwood skid will burn for about 80 minutes, that would work out too around 60,000 btu every 80 minutes . . . I should be able too come up with 12,000 btu an hour easily . . .

Here is a pic of the skids that I burn, since I cannot figure out how to get the $#@^& things where I want em ! - there at the bottom. .

oh ya, the plastic pail has been up too around 160 F so far . . .

Any bet's on when it starts too leak ?

I'm thinking of adding another 5 gallon pail, that way I can stick with the 2 or 3 degree F a minute, but have 66 lbs of water . . . lots more heat - more water . . .

Dave Lot : It looks like you have room for one of those ~17 gal~ grease drums for lubing cars that you can get at a muffler or jiffy-lube place, you might try a
couple of phone calls ! What are you draining your system down into ?! Best Big AL

allen lumley wrote: What are you draining your system down into ?! Best Big AL

Right now, I am only heating about 4 gallons of water, and if you look closely at the pictures, you can see that the top of the pail is level with the bottom coil on the stove. . . drains back good, and has the benifit of hot air rising, so the pump body stays wet, and the heat rises up the copper and away from the pump . . . (so far) . .

Update for ya . .

I have not been able too fire up the rocket for a couple of weeks now, so I thought I would record the temps as it heated up. . . . first picture.

After the stove was up too operating temperature, and the shed was a bit warmer, I thought I would add the water too the pipe, and see what happens . . one note for you guys . . the stove REALLY TAKES OFF - when you circulate ice water around the barrel . . . really improves the draft of the stove . .

I do have one question for all you guys out there, when the stove is up too temp, and burning nice and HOT . . . what would cause black smoke out the chimney ? I was burning the above hardwood skids, and this is what it was doing for a while . . . second picture . .


With the cooler ice water circulating I did manage too shatter my old temp record . . here is the new high temp record from the top of the barrel - have no idea what it would be in the burn chamber itself . . . third picture . . .

A small side not for those interested . . the inner pipe I used for the riser is almost totally gone . .. all that is left is the clay / perelit core . . which is still workin great ! first pic. looking down into the riser .. .
You know it's working right, when the pipe cap is still clean - silver - second picture . . nothing but steam . . most of the time . .
Third picture is a lesson in putting too much wood into a cold (27 F) rocket stove . . .

Thanks for sharing Dave!

Glad to see your set up is working out nicely for you.

Update for you guys. . ..

I finally got around to adding the second 5 gallon pail to my system, bringing the water level from around 33 lbs - up too 73 lbs. You can see in the picture the 1.5 inch ABS pipe that is used for a thermosyphon effect . . the water is pumped out of the bottom of the right pail, thru the coil around the stove, and back into the left pail . . it then thermosypon's back into the right pail. The temperature probe is in the top of the right pail. - first picture.

I have drawn a line in black marker, so that for every test, I can replace any water that has steamed off . . about 1/8th of an inch per test burn...

The hottest I have been able too get this setup, the way it is now, is 140 F - the temperature just stays at 140 F. I am using uninsulated pails, so there is alot of heat loss there, so my theory is, that if I can get a 3 degree temperature rise STARTING at 120 F - with this setup . . I will have enough heat to warrant connecting this thing too my house. .. right now, I am test running idea's . . . then I can install a proper insulated tank too work with . . and really start heating things up !

For the last week, it has been around -20 C or in my terms , -4 degrees F . . I have not had alot of spare time, so I have only been doing 2 hour test burns, whenever I get the chance...

2 small cups of ash is all I get from a 2 hour burn . . which is really funny, since whenever I go thru the local dollar store, they sell "wood stove" shovels - pails and brooms . . one shovel would hold three days worth of fire - one pail would do me for the entire season, and the broom would not even fit in the opening . . hee heee heee - I love my Rocket. - second picture.

Here is the results of the test burns, Having almost 100 lbs of water heated up too 120 F, really helps too keep the heat in the shed. That first day, I was really worried about the low temps, and the fact that it was only 45 degrees in the shed . . I did not take into account the water at 113 F . . worried all day that the pump would freeze, went home and the temp had only dropped by 2 degrees ! You can see on Thur...Fri..Sat... I did not do a 2 hour burn on fri.. to see how that would effect the temps... still did not hit the freezing point... Last week, I heated up the shed on Sunday afternoon, and the water in the pail on the floor did not freeze till friday... when it's -4 F outside, 43 F seems downright warm inside! - Third picture

more pics for ya. If you view the page with the number, they do come up right side up....

As promised here is a pic of the white board with the numbers on it . . the top half is how long it takes for the shed too cool off, the bottom half is my warm up burn today . .

Keeping in mind, that the shed is fully insulated - 2x6 - walls - floors - ceilings. . .

I called the building inspector today, too see if he can help in any way to get this thing w.e.t.t. certified . . he is going to make up a list of contacts for me . . still working on making this thing legal . .

Beautiful write up Dave! I really appreciate being able to follow your build and the performance of the stove once it was complete. It is an inspiration.
AL

Well, I stopped in too see the inspector, and he handed me 2 full pages of names and addresses . . all the w.e.t.t. cert guys in this area. . . as soon as the snow melts and it warms up a bit, I will be looking into this somemore. . .

Keep ya updated.

Dave Lot wrote: I will be looking into this somemore. . .

Keep ya updated.

Here is an update for you guys . . .

I finally found a w.e.t.t. certified guy too tell me what is going on with this thing. . . and it ain't good. First off, it was built too close too the wall . . even with a STEEL heat shield- and it has too be steel - nothing else will do the job - it has too be 24 inches from the wall . . no exceptions . . next, ABOVE the mass, the clearance has too be 5 feet AT LEAST . . .. I have only 4 feet clearance . .
The chimney is mounted in the wrong direction - draining down instead of up - which I knew already . . but I have too put in a double wall insulated chimney - a thousand dollar unit . .
Around the fire box - I would have too put a 48 inch spark shield on the floor - not including the "height of the stove from the floor" . . . and "traveling distance of sparks" . . .
And finally, since he does not really know how it was put together (did not bother with the pictures at this point) he would not feel comfortable certifying this stove as it sits . .

I could keep calling people, but at this point, it seems rather pointless . . . .

Dave : Thanks for sharing, as a cautionary tale there is much to learn from your experience, give it a little time and jump right back in again !

For the good of the Crafts ! Big AL

When I installed the solar panels I also picked up the enphase monitoring system.

Found out the chimney was shadowing one of my panels really badly . . so the chimney had too go . . all I did was remove 2 - 3 foot sections of pipe, and placed the cap on the elbow. . . see pic.

Will have too see if I can compromise and replace a 3 foot section while not blocking the panels . . .

here is what I found with the panels..