I have made several other types of stoves from soda cans and have not been as satisfied as I am with the Penny Stove. The Penny Stove can actually be used as a multi-fuel stove by flipping it over, putting a piece of screen in the bottom and using an esbit, or fire starter.
The stove is very efficient and can easily bring 3 cups of water to a boil fairly quickly. It doesn't require a primer bowl to light it, and is extremely light weight. Can stoves are the lightest weight stoves I have seen. They are much lighter weight than the majority of commercial stoves on the market today.
Though I mostly do boil-in-bag meals, I have tested the simmer ring for the Penny Stove. My impression was that it does exactly as the creator of the stove claims. It takes much longer to burn the same amount of fuel with the simmer ring than without. I was able to easily cook a pot of rice. This was regular rice that takes 20 minutes to cook; not minute rice.
The one issue I did have with this stove is that it must be fairly level on the ground to work properly. The penny must also be exactly over the hole in the center of the stove to properly function. However, this is not enough of an issue for me to discard the stove. I love this stove and plan to continue using it on all my trips.
A beverage-can stove, or pop-can stove, is a do it yourself, ultralight, alcohol-burning portable stove. The simple design is made entirely from aluminium cans, lending itself to countless variations.
Total weight, including a windscreen/stand, can be less than one ounce (28 g). The design is popular in ultralight backpacking due to its low cost and lighter weight than commercial stoves. This advantage may be lost on long hiking trips, where a lot of fuel is packed, since alcohol has less energy per weight than some other stove fuels.
Of the available fuels, methanol delivers the least energy, ethanol somewhat more, butanol is hardly ever used, and isopropanol delivers the most. All but isopropanol burn with a smokeless flame; it can provide both light and heat.
In 2003 posted the original instructions for a hiking stove that I had been developing for many years - one that is dependable, safe, lightweight, fast, efficient, but is still simple to make and use. I called it the Penny Stove.
This site documents the response to the first alcohol stove that is good enough to compete with gas stoves and keep canisters out of landfills. Most alcohol stoves will boil only two cups of water, but the Penny will sterilize two quarts of 45° water with only 2 oz. of fuel. It will bake scones, or simmer a pot of real rice for 20 minutes with 2/3 oz., and make tea for two with 1/2 oz..
The penny pressure regulator and simmer ring combination let it function as two stoves. It can prime and boil a quart of water just 20 seconds slower than a gas cook-top, or simmer at max efficiently for almost an hour. Web reviews from around the World show that it "performed like a champ" with a wind chill of -9°, "excellent" even with 50 mph wind gusts, and "great" at the top of Mt. Whitney - 14,491 ft..
Independent tests document that it heats faster, uses less fuel, simmers longer, and packs lighter than any commercial alcohol stove. It combines the features and performance of three basic designs - the efficiency of a high pressure/Photon Stove, the ease to fill and light of a double wall/Pepsi Stove, and fast heat of a tub/Cat Stove. So simple that you can build a rough one on the trail with a leatherman or good pocket knife - no insulation, ruler, epoxy, needles, or tape. If you have played with homebuilt stoves before, this one should be a snap. If not, this site contains help from generous people around the world.
Aluminium-can construction
Three-piece beverage-can stove (exploded view).
The stove is made from two aluminium can bottoms. An inner wall is cut and rolled from the can material. A ring of holes is pierced into the top with a pin. Parts are glued with high-temperature epoxy, or sealed with thermal foil tape, although this is not strictly necessary. Total height is less than two inches (50 mm), though dimensions may be increased to hold more fuel or decreased to take up even less space.
The choice of aluminium has several advantages—light weight, low cost, and good thermal conductivity to aid vaporization of fuel. Modifications to the surface such as inking or painting a dark color increase the amount of radiant thermal energy captured by the stove body and change the stove's burn profile as a function of time, fuel load, and ambient temperature. Many designs require priming to get started and most are regenerative and stable during operation. Alternative construction materials have been used, including stoves made of tin cans such as cat food tins, tuna cans, and juice cans—the basic design is very similar.[3] Windscreens/stands can be fabricated from tin cans, cut to size with ventilation holes added. Steel beverage cans of the classic 12 ounces design are still in limited use and while they are heat resistant, their coating will burn off and they will rust if not cared for.
Operation and performance
Each stove is designed for one or two people. When used to cook larger meals (greater than 2 cups (0.5 litres)), it is less efficient than a more-powerful stove which delivers more heat to a pot. This is because a longer cooking time is required, during which more heat is lost to the surroundings.
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 (requiring 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 the fuel runs out.
Ratings
Time to boil 2 cups (500 ml): ~4-12 minutes (45 ml of fuel)[4]
Time to boil 4 cups (1 l): ~10-24 minutes (90 ml of fuel)
Burn time: ~10-20 minutes (60 ml/4 tablespoons of fuel)
Boil times can be significantly reduced by using a pot of the appropriate diameter (to reduce heat loss up the side of the pot) and wind screens which maximize efficiency.[5]
Time to boil 2 cups (500 ml): ~5 minutes at 6500 ft (2000m) altitude with ambient temp of ~45F (7C) and water temp of ~55F (13C).
Comparison with other stoves
The stove can outperform some commercial models in cold or high-altitude environments, where propane and butane canisters might fail. Roland Mueser, in Long-Distance Hiking, surveyed hikers on the Appalachian Trail and found that this stove was the only design with a zero-percent failure rate.[6]
Fuel usage (by weight) is about fifty percent greater than a butane/propane stove.[7] Can stoves weigh less than an ounce, compared with three ounces for the lightest gas stoves. Many commercial stoves also require special fuel canisters, adding to overall stove weight. No such canisters are necessary in a can stove; denatured alcohol can be carried in virtually any lightweight container, such as a plastic soda bottle. The weight advantage of the beverage-can stove is diminished by the greater fuel consumption (especially on longer hikes), but may still be offset by its reliability and simplicity.
Other attributes of the beverage-can stove are its nearly silent operation and its suitability as an emergency backup.
Denatured alcohol is a (relatively) environmentally-friendly fuel that does not leave a residue or soot. Denatured alcohol is commonly available at camping outfitters and hardware stores. Denatured alcohol is toxic to drink.
Non-toxic pure ethanol is rarely used as stove fuel in the United States, since it is usually subject to a liquor tax. However often the cost of pure ethanol is worth carrying on hikes as it has some medicinal use including treating stings and bites, as a coolant, and antiseptic. Pure ethanol also has a recreational application in flamed desserts such as fruits flambe, despite expense.
These stoves operate marginally on 90% isopropyl alcohol, poorly on 70% and not at all with 50%. Water typically cannot be boiled with isopropyl rubbing alcohol, but if the more rarely found (still inexpensive) laboratory grade or "gas drier" is used, and the sooting is dealt with by applying a little soap solution to the pot, the fuel value of the alcohol will reduce boiling times, not increase them.
Unsealed alcohol stoves are inherently dangerous, since spilling is possible and the fuel burns with a nearly invisible flame. Trangia offers an anti-flashback fuel bottle with an auto-shut-off pourer. If a spill occurs the best course of action is to step back and let the alcohol burn up. A stove with a deep well is wind and blow-out resistant—blowing into it can send burning alcohol flying. A stove with a small, shallow well, or a central wick may or may not be blown out to stop it from burning. A safe and lightweight snuff cap or simmer ring is added to some stove designs.
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