Today I built my first rocket stove prototype. I’ve been pondering it since training when Joe Otts displayed his rocket stove. It is really an ingeniously simple design and there is much posted on
the web about it. My main dilemma has been finding a simple and inexpensive design. After several iterations of sketches I landed on using the infamous Fijian breakfast cracker bucket and egg cartons. Since everyone I have met in Fiji eats breakfast crackers and eggs I knew I couldn’t go wrong.
I started the stove by forming an “L” shape from two egg cartons. I wrapped the L in duct tape and inserted 3” nails into the short leg of the L halving it. This will later form the platform to hold the wood and allow air to circulate below the wood and up the fire shaft. The fire shaft formed the longer section of the L and rested on the bottom of the bucket. There is about a 2.25” gap surrounding the L on the sides and a 4” gap at the bottom of the stove, or top of the bucket. The bottom of the bucket will be the top of the stove when completed.
Samalu let me use left over cement from the water tank project and some old wire mesh he had lying around. We sifted some beach sand and mixed the cement with half sand and half concrete.
By the way, here is a short diatribe on concrete vs. cement. If you have ever confused the two around anyone that’s been in the construction industry for more than two weeks I’m sure you already know the difference as he quickly reprimanded you. I can still distinctly remember the time I called a concrete truck a ‘cement’ truck two days into my first internship on the Baylor Student Life Center Project and was verbally abused as if I had asked a Baptist preacher’s daughter to dance and drink a beer at the same time. Cement is the gray powder used to mix with sand, water, and aggregate. Concrete is the combination of the ingredients. It is much like flour is to bread. So don’t call a sidewalk a cement sidewalk or a gray block a cement block. They are concrete.
Ok, back to the rocket, or in my case, bucket stove. Once the concrete was ready, I placed the mesh reinforcing and poured a bit into the bucket. I then placed the L shaped stove chamber and slowly filled the bucket around it. It went relatively good except for two major incidents. The first one was the chamber started floating. I shoved it back down but had to be careful not to crush the egg cartons. The second problem was I ran out of concrete. This was a stupid mistake but luckily we had enough cement left over and Samalu whipped up a quick batch. After topping off the bucket the chamber still wanted to float to the top so we placed a large rock on top and this seemed to do the trick. In the end the egg carton was probably not the best choice. My aim was to find a form that was cheap and easily removable. Wood would have required two pours, screws, and a carpenter with a skill saw. PVC would have worked best but I couldn’t find the right size lying around and didn’t want to purchase any as it would have defeated the purpose of my main objective of creating a cheap stove. Next time I might try
making a form from multiple layers of strong cardboard. I should no more tomorrow when we pop
the stove out of the bucket and see if everything held together.