Rectangular tubing question

I have some 5" x 2.5" with .25" wall tubing.

I'm planning on building a rocket stove with it very shortly.  And when I say very shortly, I mean all the parts are cut, cleaned and ready to be welded, but before I do that, I thought I should ask here.

I've never seen anyone use this configuration of tubing.  Has anyone had success or failures with it?

My current configuration is about a 14" riser with a 45 cut on the bottom and a 8" feed tube.

This is what I'm thinking (http://a360.co/2jjNrjZ)

I'm also thinking I can either drill holes beside the combustion chamber and put a baffle there to regulate air and/or I can run the air up the side instead of underneath.  I'm leaning towards having the air feed come up the side.

Any tips?

I can't see your drawing at the link, but what you describe sounds iffy. The thin cross section (2" x 4 1/2" inside?) will allow massive cooling from the surfaces compared to the combustion volume, and it may not get hot enough for good combustion. The riser being less than twice the feed tube height may not have enough draft to keep the fire going in the right direction. If you drill holes near the base of the unit, you will be allowing the fire to travel up both the riser and feed tube. The air intake needs to be through the feed opening to keep fire from burning back up the feed. My experience with an L-tube rocket (built of cob) is that the fire eventually travels back to the mouth of the feed and involves the whole of the sticks, though if you had an uninsulated steel tube, it might be cooled enough to not reach ignition at the mouth.

What purpose do you intend for this stove? It is pretty small for more than direct heating of one pot.

Glenn Herbert wrote:
What purpose do you intend for this stove? It is pretty small for more than direct heating of one pot.

Here's an image.  I'm not sure why that link won't work.  As soon as I try to use it, it's like my file disappears and I have to recreate the link.



I think the riser will be about the right height ratio according to what you're saying.  I didn't really explain everything very well.

As for the baffles, point taken.

As for the L tube combustion feeding backwards, I was thinking about creating a J tube configuration with a wood "cage" so it can be self feeding without creating a chimney on the wrong side.  I've also seen a very elegant solution which is to put a heatsink on the feed side of the combustion chamber so there is a definite cooling on one side and a direction for the heat and smoke to go.  I can see why a cobb stove would eventually uniformly heat up and then cause a backdraft.  I believe the heatsink should resolve this.

Insulating the chimney will also help with this.  It's not in the drawing because I'm not good enough at Fusion yet.

The purpose of this stove is for cooking.  I live in an apartment, and I'm hoping to be able to cook with a small amount of resources and without heating up our place in the summer.

I'm hoping to make a stove which burns efficiently enough, that I won't get complaints from my neighbors.

I'm guessing that a rocket stove will burn more efficiently than a charcoal stove for instance. I also want to be better prepared for power outages.

Dear lord, I can't seem to link that image if my life depended on it.