Need help building a rocket stove.

[tonstwo]

Hi guys, this is my first post here, and I need help.

I've built a very small rocket stove and I think I may have done something wrong, since the outer part of the stove heats up and I don't think it's supposed to, and it's generating much smoke. I haven't taken much time playing with it and trying to figure out the best way to burn wood.

I made the rocket stove out of metal cans, and ash+soil+cement for the insulation. I think something's wrong with the insulation. This is my first try though, and mistakes do happen. But I sure would like to have a working, efficient and preferably self-feeding rocket stove. I also prefer it to be movable (if not portable), so laying bricks won't do.

I live in the Philippines by the way.

 

[k15n1]

There are some tricks... Look to see what others have done. Even looking at youbtube videos for approximate dimensions can help. I had problems in the past with an undersized air intake. Doesn't seem like it should matter, but it did. Luck.

 

[tonstwo]

Is it relative to the size of the rest of the stove or does it just have to be big enough?

 

[~gd]

Is it relative to the size of the rest of the stove or does it just have to be big enough?

It is relative to the size of the fire and to a lessor extent the quality of the fuel. The fact that you are getting a smokey burn makes me think it is starved for air.

 

[Joel_BC]

I have not built one, but I can imagine that if I did I'd be in the same position you are, tonstwo.

Youtube resources have been mentioned. Here's a couple of Youtube vids by a guy who's spent a lot of time working out practical design details:
http://www.youtube.com/watch?v=P6ValmUnjz4
http://www.youtube.com/watch?v=yRLR07GRgvQ
You can comment on Youtube videos, and often the person who posted the video will respond to your comment (or question).

There are quite a few others who have posted vids about rocket stoves, of course.

We have a member here at SufficientSelf - Paul Wheaton - who is very interested in rocket stoves. He's posted many videos, but here is one of his videos on Youtube:
http://www.youtube.com/watch?v=LfKHVoCY2so
Paul is partial to built-in designs with a lot of thermal mass, such as mortared stone. Still, he's a guy who probably knows a lot that might be helpful to you - and some of the info from built-ins might be transferable to your questions. You could try messaging Paul here at SS.

 

[k15n1]

Is it relative to the size of the rest of the stove or does it just have to be big enough?

The exhaust must be adequate height and correct diameter. Too big and you don't get a good draft because the thermal gradient is not uniform in cross-section. Too small and you're limited by fluid dynamics. If it isn't a tall enough chimney it won't draw either. Too long of a chimney and it's hard to start.

Don't worry, you'll get it.

 

[tonstwo]

Never thought that it would involve so much measuring, planning and science (now makes sense since it's supposed to be very efficient). Guess I wasn't thinking logically. Thanks guys, I'll have to do a bit more reading on this.

 

[k15n1]

Reading certainly has its place, but some of it is empirical and you'll figure it out by trying.

 

[k15n1]

Any luck?

 

[EvoQ]

If you are getting allot of smoke then you have your Air/Fuel Mixture way off. The whole purpose of a Rocket stove is to Burn the Fuel(wood) at a very high temperature. Hence there should be little if any smoke. Just like a car that runs either Rich (too much Fuel, not enough sir) or Lean(too much air, not enough fuel). It's as simple as that, I would be willing to bet that you are not allowing enough air into the combustion chamber quick enough causing lots of Smoke. If we had a picture of your project we could better help you decide a fix. Take a picture and post it up so we can get an idea of what is going on with your design.

Hi guys, this is my first post here, and I need help.

I've built a very small rocket stove and I think I may have done something wrong, since the outer part of the stove heats up and I don't think it's supposed to, and it's generating much smoke. I haven't taken much time playing with it and trying to figure out the best way to burn wood.

I made the rocket stove out of metal cans, and ash+soil+cement for the insulation. I think something's wrong with the insulation. This is my first try though, and mistakes do happen. But I sure would like to have a working, efficient and preferably self-feeding rocket stove. I also prefer it to be movable (if not portable), so laying bricks won't do.

I live in the Philippines by the way.