How to Build a Lightweight Alcohol Stove
by Dave D.
- 3 Soda Cans per person
- Pocket Knife or Hobby Knife
- 12″ Ruler
- Permanent Marker
- Half-Round Metal File**
- Aluminum Tape**
- Denatured Alcohol (fuel) Do not burn Isopropyl Alcohol. It doesn’t work as well and it has a dirtier flame.(** Optional)
While there are many different styles and instructions for making these kinds of alcohol stoves, I have found this method to be one of the easiest and generally the cheapest. The most important thing to remember is safety first! Never cut toward yourself or others and make sure you have a clean work area. Be careful working with the sharp edges of the cans.
The first thing you want to do is rinse out the cans unless you want to be working with sticky fingers. The stove is essentially made from the bottoms of two cans interlocking with the other. Take one can and use a pushpin or thumbtack to punch 14, 18, or 22 holes evenly into the can around the outside of the rim. The different number of holes makes the stove either; burn hotter with more holes and use more fuel, or burn longer and burn a bit cooler with less. I prefer 18 holes spaced evenly around the bottom edge, but experiment and try what you want.
On the can you punched your holes into, you are going to take a knife, or preferably a hobby knife to score the inside rim of the can’s bottom. This will be your opening to pour in the fuel and light the stove. Make sure you leave the ridge intact because the inner wall will sit in the rim between the two can bottoms. You can use a file to smooth down the inside edge you just cut for safety purposes.
Next, the bottoms of the two cans need to be cut to 1 ¼” tall (measuring from the very bottom to the side-wall, and the measurements have to be pretty accurate to get a good seal with the inner wall. Now turn the other can you haven’t punched any holes into upside down so that the can is “right-side up” if it still had a top. Then make 4 slits ½” long (one across from the other making a plus sign) evenly around the now “top” edge of the can. This is so your stove top can fit into the other can. Don’t put them together yet. Now we make the inner-wall.
From the center of a third soda can use scissors to horizontally cut off the top and bottom of the soda can as close to the curve as possible so that you have a cylinder with ragged edges. Cut vertically straight across the cylinder to form a long rectangle with ragged long sides. Lay the aluminum down on a cutting surface and place a ruler on top parallel to a long side. Draw out a rectangle 1 ¾” wide and 7” long. Trim off one ragged long side with the scissors using the ruler as a guide. Measure 1 ¾” from the new clean edge and repeat the cut on the opposite long side. The long sides of the rectangle should be as parallel as possible. Trim the ends so that the rectangle is 7” long.
Cut a slit into each of the long sides of the rectangle. The two slits should be 6” apart and each long side of the rectangle should have only one slit (on opposite sides). Slit depth (or length) should be slightly more than half the length of a short side, or about ¾”. If your rectangle is 7” long, the slits should be about 5/8” from each end.
To allow fuel to flow from the middle of the stove to the perimeter, make three gaps along one of the long edges of the rectangle. Measuring from one of the slits, make marks with a marker at 1”, 3”, and 5”. To make a gaps, cut 2 parallel slits about 5 mm (3/8”) deep and about 3 mm (1/8”) apart into the edge of the band. Fold the tab 180 degrees up against the painted side of the rectangle or bend the tab back and forth to break it off.
Interlock the two slits of the long rectangle to make a circular band. The circumference of the band, 6”, should be the same as the circumference of the ridge on the bottom of a soda can. Or, to put it more functionally, the same as the circumference of the circular groove on the inside of the soda can bottom. It is possible to interlock the slits so that the ends of the band are on the inside or the outside of the formed cylinder. Now we assemble.
Insert the cylindrical band into the groove of the stove bottom. The band should be positioned in the bottom stove section so that the edge with the gaps which allow fuel flow pointing down. The top of the band should extend 5/16” to 3/8” higher than the top of the bottom section. This ensures that the top soda can will rest against the band and not the bottom section. If size adjustments are required it is usually easier to re-cut the band than to re-cut the bottom section. When fitting the top and bottom soda can sections together, make sure the top can with the holes you punched fits over the OUTSIDE of the bottom can. When the band (inner-wall) is positioned correctly, press the two sections together tightly. If you made your band correctly the upper and lower sections and the stove ends should be perfectly parallel. If you are satisfied your stove fits together securely, you can seal it even further by using aluminum tape to seal the junction of the top and bottom cans.
Now we can light ‘er up!
Add Denatured Alcohol to the center of the stove and light it, preferably with a longer “stick” lighter or matches. Be careful, this stove lights easily but you won’t see an alcohol flame unless you are in low light. The stove will sputter for a half minute or so until the fuel heats up enough for an even burn out the burner holes.
You can use different size cans to achieve different results but many people choose to use the 24oz beer cans as an alternative to soda cans. The larger diameter can will allow for more fuel enabling the stove to burn longer. This stove is meant for ultra-lightweight hiking or backpacking for one or possibly two people and it will boil enough water quickly enough for two.