Saturday, June 07, 2008

Rocket Stove

I stumbled across the rocket stove on one of the many outdoor/survival skill websites I frequent. The stove has several advantages over an open fire when it comes to cooking. The two major benefits are less fuel is needed and less smoke is produced.

After dreaming about it two nights in a row, I figured I better make one!

I gathered all the materials and tools I needed. I didn't end up using the small soup can or the wood chips (more on that later). Also I used another pair of snips and work gloves after I cut myself on the metal.

I cut out a soup can sized hole in the side of one large and one small coffee can. After removing the remaing end of the soup can I inserted it through the holes in the cans. I filled the space between the coffee cans with insulation. The idea is to keep all the heat in the cylinder and ultimately directed up to the cooking vessel. This is something you can't do well with a normal fire pit.

Ideally I would have used wood ash from a fire. Unfortunately I don't have a fire pit anymore so I had no wood ash. I opted for flammable wood chips! I reasoned that they wouldn't be touching flame and there wouldn't be enough oxygen to ignite. As it turned out I was wrong. During my first test they did burn. I doused the whole thing with water before it got out of hand. I had to settle for sand as my insulator which isn't very good since there aren't many pockets of are between particles. When I find wood ash, I'll swap.

I used the bottom of the other large coffee can to make a cover to hold the insulation in. I also decided to leave four tabs sticking up to give the cooking vessel something to sit on.

The soup can has a platform in it. The fuel goes on the platform leaving the bottom half open for oxygen to enter. By only burning the tips of the wood, less smoke is produced. As the wood burns down, it is pushed further into the stove.

Here you can see the pot resting on the tabs.

I tested the stove by bringing one quart of water to boil using only the tinder and wood pictured below.

It took 10 minutes although I let the fire die a little so in theory it could have boiled faster. As you can see in the picture below I didn't need all the wood.

To increase the efficiency of the stove I could add a skirt around the pot that would direct hot air up the sides of the pot. The sides of the stove were hot to the touch so thicker insulation would also be an improvement. That would require a larger can though.

While not a primitive tool, this stove is pretty cool and very practical in an urban survival situation. With proper ventilation this could be used indoors due to the low level of harmful emissions.

There are some good how-to videos with various size stoves if you search Google Video.


Mungo said...

That's very cool - thanks for sharing this idea. Now you've got me thinking!



fooiemcgoo said...

sorry i missed your birthday.

happy birthday.

cool project. this is actually one of my favorites. looks like it took a while to make and i like how well it works. it also seems much less primative then say, bone/rock tools and the like.

also, it was good hanging out with you again. we had some good times.

Bleach n Sheets said...

I think this could also be turned into some sort of instrument with a little enthusiasm. Nice oven!

Urban Scout said...

I love rocket stoves! I just spent the last two weeks cooking on one. They're really great. Nice blog/pics!

SpiritWalker said...

I have built something similar at bush camps out of flat sand stone, lime stone and just about any kind of flat, thin stone. Take note; Do Not Use Any Stone of a crystaline nature or stone with quartz in it. It will explode impressively when heated, hopefully when you are not within 30 meters. For insulation i have used sand mixed with pea gravel, loose earth mixed with green bark and green woody plant stocks. This is not as good as asbestos but it is the best i could find in natural surroundings. Also, after it is built, mound and pack earth around it. This acts as added insulation and allows you to crouch beside it without surfing the heat. It also adds a safety factor against accidently bumping or touching the stove itself. Also, in cold or cooler weather, pile stones around it before covering with earth. It will produce heat for hours after the fire burns down.
Excellent stuff here, thank you.

Anonymous said...

In an urban survival situation you will have abundant fiberglass insulation. This pink or yellow fluff is also commonly found blowing around in the wilderness also. I have on several occasions found everything I needed to make a rocket stove out in the desert (silly humans leaving garbage everywhere!) I have found that using fiberglass is advantageous for several reasons; nonflammable, lightweight, excellent dead air space, abundant/cheap. Nice photos! keep up the good work!

Sassmouth said...

Fiberglass seems like a good idea. I actually just replaced the sand in mine with white wood ash. It's nice and light weight.

Jarom said...

Another option would be vermiculite from your local gardening store (support the little guys).

javieth said...

I love the big stove specially because i like to cook all kind of recipe, how ever i prefer to have a reasonable place. Actually i saw a beautiful stove in a house that was published in costa rica homes for sale it was big and beautiful, i think i will go there because it catched my attentio.