Beverage-can stove
A Soda can stove is a homemade, ultra light backpacking stove. The simple design is made entirely from soda pop cans and burns denatured alcohol. Countless variations exist. Pepsi cans are often used because they have a bottom shape that lends itself to securing the stove's inner wall. It is also known as a Pepsi can stove.
The stove weighs 0.4 oz (10 g) and will boil two cups of water in five minutes with two tablespoons (30 ml) of fuel. Total weight, including a windscreen/stand can be less than one ounce (30 g).
Backpackers can save about one pound (450 g) of weight with this stove, compared to commercial stoves and their fuel canisters. The advantage may be lost on very long hiking trips, however, because the stove is less efficient and requires more fuel, especially when cooking for more than one person.
History and design
The basic design dates back more than one hundred years. It consists of a double wall gas generator, a perforated burner ring, and an inner pre-heat chamber. A similar design was patented in 1904 by New York coppersmith J. Heinrichs. Trangia has been selling a commercial version of the design since the 1950s. Interestingly the Trangia stove burner is not made from aluminum, even though all the other associated parts that come with it are. A plastic bag is provided for the burner so that when packed away the two dissimilar metals do not cause corrosion.
The double wall acts as a gas generator, transferring heat from the flame to the fuel. The effect enhances combustion, producing more heat than other passive designs. The inner wall also creates a convenient preheat chamber for starting the stove. Once the fuel has warmed up, its vapor will travel up the hollow wall, through the perforations and form a ring of flame. Vapor also rises from the center of the stove, but will pass through the ring of flame for efficient combustion, as long as a pot is over the stove.
Aluminum can construction
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The stove is made from two aluminum can bottoms. An inner wall is cut and rolled from can material. A ring of holes is pierced into the top with a pin. Parts are glued with high temperature epoxy. The total height is less than two inches (50 mm).
Windscreen/stands can be fabricated from tin cans, cut to size and with ventilation holes added. Aluminum should not be used.
The choice of aluminum has several advantages; light weight, inexpensive, and good thermal conductivity to aid vaporization of fuel. See the external links section for building instructions.
Operation and performance
The stove is designed for one or two people. Cooking larger meals (greater than 2 cups (0.5 l)) is less efficient than a more powerful stove. This is because a longer cooking time is required during which more heat is lost to the surroundings. A more powerful, pressurized version is shown below.
Operation
To use the stove, a small amount of fuel is poured into the stove and ignited. The pot is then placed above the stove, on a windscreen or stand. The flame is small at first, only burning from the inner chamber. Once the fuel has warmed up, about one minute, its vapor will pass through the perforations and form a ring of flame. Enough heat from the flame is passed to the fuel to maintain full combustion until fuel runs out.
Ratings
- Heat output: ~4800 BTU/hour (1400 W)
- Time to boil 2 cups (0.5 l): ~5 minutes (<2 tablespoons (30 ml) of fuel)
- Time to boil 4 cups (1 l): ~12 minutes (<3 tablespoons (45 ml) of fuel)
- Burn time: ~9 minutes with 2 tablespoons (30 ml) of fuel
- Burn time (full): ~30 minutes with 5-6 tablespoons (75-90 ml) of fuel
Comparison to other stoves
The stove can outperform some commercial models in cold environments, where propane and butane canisters fail. In Ronald Mueser's book Long-Distance Hiking he surveyed thru hikers on the Appalachian Trail and found that this stove was the only design with a zero percent failure rate.
Fuel usage (by weight) is about fifty percent greater than a Peak I or MSR Pocket Rocket. The soda can stove saves about one pound (0.45 kg) of weight over these models for an overnight hike. The weight savings is lost for hikes greater than two weeks due to the additional fuel usage.
Other attributes of the soda can stove are its nearly silent operation and suitability as an emergency backup. Ethanol is a nontoxic, environmentally friendly fuel that doesn't leave soot. Unsealed alcohol stoves can be inherently dangerous, however, since spilling is possible and the fuel burns with a nearly invisible flame. Extreme care should also be taken when refilling a hot stove.
Variations
- Standard
- The classic ultra light weight backpacking stove. Designed for one person, lighter than commercial models of the same design.
- Inverted two piece
- Smaller and lighter than the standard version, difficult to fill.
- Side burner
- Doubles as a pot stand.
- Pressurized
- More powerful and efficient than the standard or commercial versions. A thumbnut is used for sealing the stove after filling with fuel. Heavier and more difficult to make.
References
- US Patent 560319: W.J.D. Mast (1895)
- US Patent 766618: J Heinrichs (1904)- see External links
- Berger, Karen: Hiking Light Handbook (2004)
- Mueser, Roland Long-Distance Hiking: Lessons from the Appalachian Trail (1997)