Introduction: Self-pressurizing, Chimney-type Alcohol Stove
In this Instructable, I will show you how to build one of the most efficient types of alcohol stoves: a self pressurizing, chimney-type stove.
Disclaimer: This project involves sharp tools, sharp pieces of metal, fuel, and fire. I take no responsibility for any and all damage that you do by following these directions. These instructions are for informational purposes only. I disclaim all responsibility for damage or death to property, person or animal caused by either the correct or incorrect following of these instructions. This project should only be attempted by a responsible adult, following proper fire safety protocols, and with an understanding of all the risks involved.
That said, let's get started!
Step 1: First Step - Gather Materials
First, you must gather all the necessary materials. Most of these can be found at a hardware store like Home Depot or Lowes. The stove itself is made from an Coors Light aluminum bottle can. You will most likely want to get several of these, as it can be tricky to get this to work the first time. The aluminum bottle design is also used by certain energy drinks like Monster.
You will need:
1. An aluminum Coors Light bottle
2. A pair of scisors
3. A center punch with a sharp point
4. A knife, razor blade or Xacto knife
5. A fine point marker
6. A 1 1/2 inch spade bit
7. A pin vice or a small drill like a Dremel
8. A 1/32" drill bit
9. Steel wool, both fine and coarse
10. JB Weld - I use JB KwikWeld because it sets up faster
11. A ruler or a square
12. Not pictured - needle nosed pliers and nippers/angle cutters
13. Optional - A pair of calipers can sometimes be handy for checking exact measurements
Step 2: Second Step - Prepare the Bottle
First (after drinking the beer), you will want to take a pair of nippers and remove the extra retention ring around the neck of the bottle, left after removing the cap.
Next, you will want to wash the bottle inside and out, because you won't want your workspace smelling like beer.
Then you will make a measuring ring.
Take a strip of paper, long enough to fit around the neck of the bottle, and cut it to fit exactly once around the neck of the bottle.
Then fold it in half, and in half again, and in half again. There should now be 7 equidistant fold marks in the paper (+1 for where the ends of the ring come together). Mark them with a marker or a pen and tape the ends of the strip together so that it forms a ring (that just fits around the neck of the bottle). Make sure that the markings are on the outside. We will use this ring to mark the burner jet holes.
Next, place the ring over the neck of the bottle so that it just sits above the shoulder of the screw ring, as pictured below.
Using the marker, place 8 marks around the underside of the shoulder.
We will use these as guides for the next step.
Step 3: Third Step - Drilling the Holes
Next, take your pin vice or Dremel tool with a 1/32" bit and begin drilling the jet holes, angling towards the mouth of the bottle and not straight in.
Once all 8 holes are drilled, take the drill bit, and angle the jets, up and to one side. This will create a spiral flame, and makes the burner's flame more stable to wind.
It should look like the photos when finished.
Step 4: Fourth Step - Cutting the Bottom Hole
At this point, we will start cutting the bottom of the can to accept the neck of the bottle. First, find the center of the bottom. I did this by drawing lines across the bottom holding the market on a steady surface, close to the center of the can in height, and marked four lines. The convergence of the four lines is the center of the can. Next, use the center punch to start a hole there, big enough for the point of the spade bit. Next, use the spade bit to scribe a circular line around the bottom of the can, cutting as deeply as possible. Once the line is scribed, use a pliers to enlarge the center hole until you reach the score line. If you are careful, the aluminum should start to rip along the score line. Continue all the way around until the hole is completely opened. Finally, clean up the edge with sandpaper or coarse steel wool.
Step 5: Fifth Step - Cutting the Can
At this point, we will divide the can into two pieces. Before doing this, if you want to remove the paint from the outside, now is the time. It will be much harder to do this later. First, measure the can. You will want the top half of the can, which includes the neck to be at least 1/2" longer than the bottom. Start by making marks along the can indicating the length of the cut. Next, using a marker and a steady surface, rotate the can, holding the marker still. You will get a perfect line going all the way around. Repeat this for the other end of the can. Now, between the two lines, make a plunge cut with an razor and cut the can all the way around keeping the cut as far from both lines as possible. Once the two halves are separated, use scissors to cut down to the inscribed lines, keeping the edges as smooth and even as possible. Finally, make sure that the edges are smooth, because the next step will destroy the stove if this is not done.
Step 6: Sixth Step - Assembling the Stove
Before going further, make sure that the edges of the can that have been cut are as smooth as possible. Any roughness or denting will cause the can to collapse when we push the two halves together. Use steel wool, files, and/or sandpaper to smooth the edges first. Next mix up a small amount of JB Kwik. You will need just enough to put a small bead along the shoulder of the neck. Mix equal portions of the epoxy and hardener thoroughly. Using a toothpick or other small instrument, apply a bead around the shoulder of the neck, above (I.e. closer to the open end than the bottom) the jet holes drilled earlier. Once this is applied, you have to work fast. Set the pieces together with the neck pointing up and place the bottom of the can, inverted, with the 1 1/2" hole above the neck of the can. Using firm and even pressure on a stable, level surface, push the bottom of the can over the top, until the neck is seated within the hole, and the JB Kwik fills in the gap. If you didn't use enough epoxy, you can use a toothpick to apply more to fill in the gap. Finally, trim the excess can from the bottom, carefully removing aluminum, until the bottom is even and level. Be careful here! If the inner can inverts, or crimps, or folds in, the stove is ruined, and there is no way to fix it. I have lost several otherwise perfect stoves at this step. Use small sharp scissors and be gentle.
Step 7: Seventh Step - Fitting the Fuel Port
If your stove survived the last step, you are now ready to fit the fuel port. I used 1/4-20 stainless steel nut and bolt with a knurled edge, for grip. Make a mark along the top edge of the can, in the center of the rim. Use the center punch to start a hole, and use either progressively larger drill bits or a rasp to open the hole up. You want the bolt to just fit inside and engage the threads of the bolt. Mix up a small amount of JB Kwik and apply it to one side of the nut. Use a very small amount. Then press the nut against the hole, and screw the bolt in place to hold it until the epoxy starts to set up. I set mine up to dry with the bolt pointing up, to avoid the nut coming off while the epoxy was wet. When the epoxy starts to set, remove the bolt so it doesn't get epoxied in place. Use a toothpick to remove any epoxy from the threads of the bolt.
Step 8: Eighth Step - Making the Potstand and Stove Stand
For this, you will need some additional pieces of aluminum. I used K&S Engineering Aluminum Sheet - 0.032" x 4 x 10" sheet.
I have laid out the cut pieces against a ruler, as shown below, for measurement reference.
The exact measurements are unimportant, but the top piece should fit over the neck of the bottle, that makes up the chimney. These are the smaller pieces.
The base should be sufficiently wide to prevent tipping, and can be a little less thick than the potstand part because it will not come in contact with direct flame. It should be cut wide enough to keep the stove off the ground, especially in conditions like ice and snow.
The photos demonstrate how the pieces should fit together and ultimately, how they fit on the stove.
The cross support for the base also supports the cap, as the priming pan, which holds the priming fuel that gets the stove burning in the first place.
Step 9: Ninth Step - Firing It Up
You should now wait a few hours to let the epoxy cure before firing up the stove. Take the cap and remove the plastic inner lining. You will need this cap as the priming pan.
You will need to elevate the stove off the ground or no oxygen will be able to get to the flame. I suggest making a cross support to keep the stove off the ground and hold the cap/priming dish.
You will need to put at least 20-25mL of denatured alcohol into the stove. Screw the bolt into the nut after fueling or the stove will not pressurize. Add a few mLs of fuel to the cap and place it directly under the center of the stove. When the fuel in the cap ignites, it heats up the fuel chamber in the stove, vaporizing fuel and pushing it out of the jets where it catches the flame and continues heating the stove.
Test this outdoors, on a non-flammable surface, and have lots of water around to put put a fire, in case the stove leaks fuel and ignites, or something else bad happens. Once the stove has been fired a few times, the paint on the can will fuse the aluminum together and make the whole thing much stronger.
Step 10: Acknowledgements
I would like to acknowledge the YouTube user Tetkoba (http://www.youtube.com/user/tetkoba) whose design inspired this stove. I adapted his design to work with a can available on the American market.
If you do attempt to replicate this, let me know how it turned out!
Thanks for reading!