The stove - by Robb

Here's some shots showing several views of my stove. As a cross between a rocket stove and a vita stove I think it combines the best features of both. It has an elbow style fire chamber like the rocket stove but doesn't utilize high energy inputs of building refractory bricks called for in the rocket stove.It is built from a recycled veggie oil can. The fire chamber, as seen in the middle picture, is an olive oil can with holes poked in the bottom for air flow. It has been set into a bed of mortar mix and bits of tile to insure a gap underneath to let air in. The pot sits on top of the fire chamber. I clipped 6 triangular tabs out of the top edge to let the heat flow out around the pot and create draw. The stones are set around the chamber to insulate and would be better if they were some high air content stone like volcanic tuff or some such.

As you can see in the first shot the pot is about 2 inches in diameter less than the can but would be better if it were about 1-1/2" larger. The smaller gap would hold more heat to the sides of the pot which is visible in the third photo as completely immersed in the cooker. The last shot shows how small and smokeless the fire can be. Most of the smoke is at startup. This is due to the moisture slowly being driven off by a low heat fire. As the fire gets hotter new fuel introduced smokes less. I also dried the fuel for at least 2 weeks prior to use.

I boiled about 6 liters of water, in two batches, for 5 minutes or more and cooked 1 dozen eggs and two ears of corn at the same time. Overall the fire burned for almost two hours and used a bundle of sticks and small scrap timber about 8 to 10 inches in diameter and 12 to 14 inches long.

All the fuel and materials for the stove were scrounged and free, since it is biomass fueled it is essentially carbon neutral cooking. The mortar mix, a small bag I found, has cement in it and thus has carbon impact. It could be done with limecrete thus lowering the carbon impact but I would have had to purchase the materials for that. My friend Graeme suggested that I could use sand or dirt.

I have several ideas for improvements; a more insulating filler material which should be filled to just under the triangular cutouts, an insulating layer on the outside of the can would be useful particularly for the top half where the pot is, a bigger pot. In preparation for FFPD November I've already collected the fuel for drying.