Picture of concrete rocket stove
Here's a rocket stove that will outlast you, but it's cheap and easy to make.  But it takes sawing concrete...   I used a 7" diamond blade on a circular saw for the occasion.
This takes three 8" x 8" x 8" blocks and a 8" x 16" x 1" slab for a base.  One block needs the side sawed out so it can make the bend. 

This is a true rocket stove, even though it is not insulated.  To start it, you may need to throttle it by putting something on top to choke the exhaust air a bit.  You might drop some dry dirt or sand down the chimney to insulate the base, but it's not needed.

It takes 1 1/4" standoffs on top for a pot so the flow is not restricted.  Use rocks or sawed off pieces of the cutout.

The only thing that needs replacing is the coffee can  in the inlet to raise the wood 1 1/2" for the air inlet.
Quick-tune3 years ago
I may be wrong, but I always thought that concrete tends to explode at high temperature - I heard it somewhere!
Tim Temple (author)  Quick-tune3 years ago
Yes, start it slow, to drive the water out of the concrete and evenly heat the whole thing.

The Russian peasants have chimneys of wood that has a layer of clay spread on the inside. It works great so long as you go slowly.
danzo3213 years ago
Seems like they make U shaped block already, for endcapping garage doors etc.
Tim Temple (author)  danzo3213 years ago
You could take an 8 x 8 x 16 beam block and cut it in half. It would only be 50% more work...
morgano3 years ago
This looks promising, but you need clearer instructions. I think I can figure it out just by looking, but you must reveal your secrets! Show us the exploded view, at least.
quzie3 years ago
This is terrific! I'm going to find a way to get the block cut! We went through a storm in April, no power for 10 days and no phone/internet for 32 days. Thanks Quzie
Tim Temple (author)  quzie3 years ago
I was thinking of using a carbide grit rod saw blade mounted on a hacksaw for cutting the block. I have the blade but it would be a bunch of work!

I cut the coffee can with sheet metal shears, but I could have done it with my Kabar knife. After cutting out top & bottom, lay it on its side in sand and punch down through the ends into the side and into the sand.