Smallwood-fired Tin-can Gasifier Stove

GasifierStove

A few days ago I took 30 minutes and finally threw together my own version of the wood gasifier tin can stove. In the photo above you can clearly see the gas igniting from the ring of holes around the top of the interior can. This is a top burning stove, meaning that you load small pieces of wood to entirely fill the interior can and then build your initial fire on top which then burns downward. Since it is the gases that are released from the wood that actually burn, they are drawn downward through the stove and then back up the void between the two cans to re-ignite at the top of the stove. This gives a strong, hot flame right under your pot.

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For this version I used three different cans. The largest was a coffee can with a “peel-off” top. This is a heavy duty aluminum foil seal that left a quarter inch rim around the top of the can that negated the need to cut open the top. Otherwise, you would need to empty the can somehow and then cut out a circular hole the diameter of the next smallest can. You can do this by drawing a circle the diameter of the interior can and then very carefully cutting out the metal with a pair of tin snips or a jigsaw. This can obviously be a pain in the ass. A down and dirty version would be with an old-fashioned “church-key” beer can opener that punches out the triangular shaped holes, making a complete circle of adjoining holes and leaving a 1/4″ edge. The interior can was from a Progresso soup, and the smallest can was of the cat food variety.

Once the top is cut out on the largest can, you make a row of equally spaced 1/2″ holes around the bottom. These are your air intake. I used tin snips to join two holes to provide a clean-out for the wood ash. The soup can has as many 1/4″ holes punched in the bottom portion as you can fit without violating its integrity. It’s top was simply removed with the rotary can opener. You then make a row of equally spaced 1/4″ holes around the top of the can 1/2″ down from the top. I used 10 holes on the larger can, and 24 around the top of the soup can.

The cat food can, which is used as a set off to raise your cooking pot, is the most difficult to deal with. The bottom of these cans are rounded over, and preserving that round-over is necessary for it to sit stably in the top of the Progresso can. This means more careful work with the tinsnips. You want to be able to cut cleanly right around the outermost groove in the bottom. It then has a row of eight half-inch holes for venting.

I think I made a mistake with the cat food can on this version. The holes probably should be adjoining the top edge. I accidentally pierced them at the bottom. I am going to make a second version of the standoff and see if changing the holes makes any difference.  In matter of fact, the number of holes used in each of the components seems to be open to debate. When I make the next model I will probably use a smaller number of holes to provide burners in the top of the soup can [at least]. I may also try making a larger version using a big tomato juice can and a tall baked-bean can.

Once the holes have been drilled, you simply start to wedge the smaller can inside the hole in the top of the coffee can with a slight rocking motion, so that you do not tear the metal rim. When it has started down, you can turn the whole rig over and just push down on the bottom of the coffee can to seat the soup can inside. If you have been careful, it will fit together so snugly that it can no longer be taken back out…. That’s why these photos don’t show the components separately.

Because my Olicamp cook-cup is nearly the same size as the set-off can, I used a 92mm fan grill from the back of an old computer case as a grate. Larger pots or fry pans will sit quite stably on just the set off.

Once the fire was established, I was able to bring eight or 10 ounces of water to a full bubble for coffee in just less than four minutes. Total burn time before I needed to add more wood was around 10 to 12 minutes. Now… there is no way to regulate the heat on this type stove. Cooking and simmering thicker foods will require constant monitoring, and stirring, to prevent them from burning. While it is not shown in the photographs, I found that it works wonderfully with the little aluminum flashing windscreen that I showed in an earlier post.

However, where this stove really proves itself a winner is in cooking or toasting things on a stick. I love to take along a little baggie of frozen, marinating meat that thaws out while I hike and cook it piece by piece over an open flame. This unit is perfect for that type of cooking. Think marshmallows!  Think “Lil’Smokie” wieners, think steak tips, or chicken chunks… hot, sizzling and with that certain kind of char that you can only get over open flames. No huge fire pit to maintain, and you can start your cooking within five minutes. Once you’re done cooking, you can maintain a nice, small fire to hang around by just adding thumb-sized stick-wood in through the top. You end up with all the enjoyment of an open fire in the tiniest of footprints. Left to burn out, the stove will have only fine, white, wood ash remaining to dispose of.  Truly “Leave No Trace”.

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