DIY wax-powered backpack stove: preparation - Frank Groffie's miscellany

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You’ve constructed the stove in accordance with the Construction page. Now you’re ready to prepare your stove for a super-remote wilderness trek. Preparation involves placing a proper battery in the supercharger and ensuring a proper quantity of properly sized wax fuel sticks.

Battery insertion

  • Open the supercharger lid. See Photo 1, below.

  • Select an appropriate battery. See Battery, below. Press a fresh battery into the supercharger, with terminals mated to their opposite-shaped terminals on the supercharger. Close the supercharger lid.

  • While you're at it, turn the four stove/pot supports inward, for compact stowage, as in Photo 1, below.

  Photo 1. Preparation for packing.                                    Photo 2. Ready for use.

Selecting and packing wax fuel

Pack your wax fuel supply in a ziplock plastic bag. One would not want wax to melt in your pack. In temperatures under 70 °F, your wax should stay solid inside your pack sitting in the sun or even in your pack sitting in a car sitting in the sun. If in doubt, double-bag your wax supply and stove, separately, and insulate them deep within clothing inside your pack. Also, stow the supercharger separate from any fuel.

If temperatures somewhere in your travels will go upwards of 70 or 80 °F, then you need to think about how high or for how long. Perhaps the most critical part of your trip, in terms of heat, will be the car ride, when you could be crossing some hot valley on your way up to the mountains. OK, so your car has AC, but you might leave your car sitting somewhere in the sun, unoccupied. Perhaps double bagging and other insulation will be adequate.

If in doubt, it may be time to consider a different wax formulation. Different types of wax melt at different temperatures. The lowest-melting-point wax (115 ºF) is paraffin, or typical candle wax. A good substitute is beeswax, with a melting point of 143 °F. It’s easy to shop online for beeswax. Another substitute would be carnauba wax, with a melting point of 180 °F. These two wax types are natural animal and plant products, and they also come with desirable burning characteristics (although I wonder if carnauba wax would be difficult to light). A good source of information for comparisons is Ross Waxes.

How much wax to pack? My tests using the stove show that 0.8 ounce of wax will bring 1 liter of water to a boil in nice weather (70 ºF [23 ºC], no wind). Figure you’ll need more fuel where the temperatures are lower and a breeze is blowing. You’ll need to multiply your estimated cooking needs per meal or per day for your party and multiply by the number of meals or days.

Or, just multiply the weight of petrochemical (butane, propane, white gas) fuel you have carried in the past by 2 and you should be in good shape (that's net weight, fuel only, minus containers). Alcohol is another matter: figure you can get by on slightly less wax than alcohol fuel.

Shaping wax into convenient fuel chunks

Wax fuel is best packed as small cubes or prisms. Pieces about 1 inch long cut from a traditional candle are suitable. Always yank out the wick before using any candle for stove fuel.

If you buy wax at the hardware store — Parowax
® brand, found in the aisle with the food canning supplies — you’ll see that it comes in convenient little slabs. Using a serrated bread knife, saw (a bit) and cleave the slabs into sticks a little under ¾ in. thick by 1-in. long.

All this work and scavenging around the house for miscellaneous candle wax result in lots of scraps. The best way I've found to convert large quantities of scraps into convenient sticks is as follows.

  • Select a baking pan with sides at least 1 in. tall.

  • Using a paper towel, lightly but thoroughly grease the pan's bottom and sides with oil; vegetable oil is fine.

  • Place enough wax scraps on the sheet so that once molten they will create a layer ⅝ in. deep. This requires careful estimation. Better to underestimate and add more scraps during the melting process than for the pan to overflow.

  • Place the pan in an oven at about 250 °F until the wax is molten. Keep a close eye on it. If it looks like it could overflow, then carefully remove some of the still-solid scraps.

  • As the last of the wax melts, stop the process, and let the wax sit for a while.

  • While the wax is still warm and somewhat soft, slice and chop it into cubes or sticks of a convenient width and length. Let these pieces cool until hard.


A good commercial alkaline battery (Duracell®, Energizer®, Rayovac®), inserted fresh, should power the supercharger a total of 4 to 5 hours. A lithium 9-volt battery (Ultralife®, Rayovac®) may last about 10 to 12 hours in the supercharger, I'd estimate. You may get slightly more or less supercharger output from a battery depending on the wattage of the fan you install. A battery weighs 1 to 1½ ounces (lithium and alkaline, respectively). First-time users are encouraged to take one more fresh battery on a trip than they might otherwise estimate is needed, for a comfort margin in case of accidental overuse, shorting, miscalculation, or other user error from inexperience. Rechargeable batteries, due to their low voltage, will not dependably power the supercharger.

The amount (liters/quarts) of water that one battery can help bring to boiling can be estimated by dividing battery life (see above, convert hours to minutes) by roughly 10 minutes.

A fresh battery can power the fan in temperatures down to some 0 ºF. A weak battery in very cold temperatures could be inadequate. Warming a battery in a shirt pocket close to one's body can help by raising battery temperature to around 95 ºF.

A loose, uninstalled battery can short (be weakened) when its two terminals touch a single piece of bare metal simultaneously. To prevent shorting, a battery can be stowed separate from metals in a plastic, paper, or cloth wrapper.

Priming fluid

The wick is typically difficult to light. Carry about 1¼ oz. of priming fluid in a small plastic mister bottle. I've found that an 80-20 mixture of charcoal lighter fluid and Coleman fuel or 80-20 mixture of diesel fuel and gasoline works well. I give the fuel bowl about eight to twelve pumps from the spray bottle before lighting the wick.


Execute this DIY project and use any resulting product solely at your own risk.

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