danny zeigler

Daniel and Peter, I will try putting a flue pipe extension on the outside of the house. That will be the easiest next attempt to get the stove working. There is a slight breeze outside and I do have some air blowing back up through my feed tube so I hope an extension will help although I don't see how I can run it up above the roof.

Chris, you said the transition CSA from the barrel to the exit chamber of the horizontal duct is mudded up smaller than it should be. Actually the firebrick transition from the barrell to the 6 inch duct is larger than the 6 inch duct. In the picture it looks like the 6 inch duct is partially mudded shut. There appears to be some clay on the inside of the duct but that is just a thin film of clay that was left after I wiped it off with a wet rag. The duct is completely open.

Hello everyone,
The structure the stove is in is an 18 year old barn that was converted to a yoga studio and then to living space. It is a gambrel roof which is the typical two pitch barn style roof. The flue goes out on what would be the gambrel roof end. It is a two story and the second story is in what would be in the barn roof. It is well insulated and it has always been heated it with portable electric heaters. The door in the picture is an exterior door. I do not want to and really cannot run a flue pipe up above the roof. There is a double door above the flue off the second story and I would also have to run the flue through the soffit overhang.


The flue is sealed up and the opening from the barrel to the flue is wide open. When I fired the stove up the smoke did exit the flue to the outside and the barrel got warm but a lot of smoke came back up the feed tube which makes it impossible to use the stove without getting smoked out.


Here is my thought about running the flue above the roof. The flue gas has lost most of its heat by the time it exits the flue outside the house. It has been pushed along by the force created in the riser. If the force is not great enough to push it out the horizontal flue it certainly is not going to be strong enough to push the warm and rapidly cooling flue gas another 20 plus feet vertically. In all the rocket stove u-tube videos I have seen I don’t think any of them exhausted above the roof. I guess I could at least try hooking on a vertical 6 foot flue pipe on to where the flue exits the home to see if that works. That would be easy enough.

The only other thing I can think of that would cause the problem is that the 20 gallon riser is on the side of the 55 gallon barrel and doesn’t come up in the middle of the barrel. This is because I tried to use a 20 gallon barrel first and built the firebox assembly for it. It also doesn’t have enough insulation to nearly fill the 55 gallon barrel. There is a larger volume of air in the 55 gallon barrel so the volume of the cross section area is not uniform at this point.

To remedy this I will have to move the entire firebox over and start again on the feed tube and barrel assembly. I guess I will try that but it will be my last attempt and if that doesn’t work I am going to take it all out and glue the carpet back down.

Thank you everyone for all the advice. I hope I can get it working right since I am getting tired of messing with it. Maybe if nothing else my rocket stove experiments can be used as an example of how not to build a rocket stove.

Well, I made the change to the 55 gallon barrel. When I fired it up but was really bummed to see that it didn’t draw any better than the 20 gallon did and the smoke really came back up the feed tube. I left the 20 gallon barrel and put vermiculite inside it. I have 1 ½” between the top of the riser and the top of the barrel. I am doing something wrong but don’t know what it is. Here are some pictures if anyone has suggestions.

Thanks Matt, That makes me feel beter. I am going to do the 55 gallon barrell this weekend. I will keep you posted as to how it works.

One other thought I had which I probably know what the answer will be. If I do what I described above would I absolutely have to put the larger insulation around the 20 gallon barrell inside the 55? It would be nice if I could just insulate inside the 20 and then put the 55 over it. Would the force of the heat in the riser push the volume out of the 55? Just a thought.

OK, first I disconnected the flue from the barrel and lit up the feed tube with leaves to see if the stove was drawing. I did get a sideways burn, the top of the barrel got warm and smoke came out where the flue would hook up to the barrel. Then I hooked up the flue pipes and sealed them up. I built a fire and got a sideways burn but also smoke coming back up the burn tunnel. I had the fire going for about a half an hour. There was smoke coming out the flue on the outside of the house and there was a sideways burn most of the time although I would get fire creep up the feed tube at times and smoke also came up the feed tube. Twice in the 30 minutes I had to open the doors and window since it was getting too smoky in the room. I think I have concluded that the 20 gallon barrel, while it does draw, does not have a powerful enough draw to suck all the fire and smoke horizontally. So I have decided to use the 55 gallon barrel.

This is what I am thinking now; I would like to cut off the 20 gallon barrel and cover it with the 55 gallon barrel. If I leave a space of 1 to 1 ½” inch between the 20 gallon barrel and the 55 galon barrel and let the 55 gallon barrel hang out into the room away from the wall I will have about 10 inches between the 55 and the sheetrock exterior wall. I am sure I can build an insulated heat shield to protect the wall . I can take a piece of corrugated tin and wrap the riser inside the 55 so that it is within 1 ½ “ from the inside of the 55. This would mean, however, that the flue pipe would not come up in the middle of the 55. I don’t see how this would hurt the performance even though the heat riser will hit the top of the 55 away from the center. I guess I will just have to heat my tea on the back of the barrel.

Of course since this is my first rocket stove this is just my guess. I would appreciate any suggestions before I go tearing this one apart.
Thank you,
danny

Chris, the floor is a concrete slab and a portion of the wall is concrete as well. about 7 feet is studs and drwyall so I will have to make an insulated air gap between the flue- barrell and the sheet rock. If I use the 55 gallon barrell I will probably,as you said, have to start all over. Oh well.

Right now Peter I have 6" round duct stubbed outside through a tripple wall sheet metal duct. I am just putting everything together and tring to get the stove to draw. The stove is on the first floor and the flue runs horizontally through the bench and then exits the house just above floor level. Are you saying that I have to build a vertical stack on the outside of the house up to the roof like with a wood stove?

Allen,
I cut the ends of the barrels out and they fit together very tightly. I put some of the heat resistant calking that is used for wood stoves around before I tapped them together with a hammer and a 2 by 4. No smoke comes out and it would probably be hard to get them apart again. Right now on the outside the house I just have the 6” flue pipe stubbed out. I also tried putting an elbow on it which I angled down at about 45% angle to see if it would help draw.
I didn’t quite follow you on laying the bricks on their side. Do you mean to raise the height of my burn tunnel 2” by laying bricks flat under the three on their side that I am using for the roof of the burn tunnel?
danny

O.K, yesterday I reworked the rocket stove. I used a hvac boot to connect the barrel to the flue. This allowed me to cut a much bigger opening in the barrel. i also changed the exit form two 90 degree turns to two at about 45 degrees and put a cleanout after them. This can be seen in the pictures. The stove still doesn not draw well at all. Smoke poured back and out the feed tube. I even shoved the fire into the burn tunnel and the fire would rocket back in the feed tube. Maybe I need to just go ahead and use the 55 gallon barrel. I could cut the 20 gallon barrel and existing 6 inch riser off and leave it and cover it with the 55 gallon barrel. I guess I would have to get a piece of sheet metal to wrap the 20 gallon barrel in to insulate it and leave about 1 1/2 inch between the new sheet metal riser and the 55 gallon barrel. Any other suggestions.