Homemade Sideburner Hybrid Alcohol Stove
One of the biggest issues I had with the many variations of the pepsi/pop-can stoves are that the inner wall on the LP side burners was a rectangular piece of aluminum that had to be spliced together in some manner. The better the fit and sealing of this inner wall, the better the stove.
To make it easy, it seemed to me that you’d want a complete circumference of a can, one that you didn’t have to splice. Just a section with the top and bottom cut off. So, I started looking around at the various cans.
Using Arizona Tea cans for the body of the stove, and Starbucks Coffee or Red Bull cans for the inner wall, I modified the many versions of stoves on the Internet to come up with my own. Not really, I simply substituted these cans for the ones in the other directions, took out the measurements, and added some guesswork and bad jokes.
- Razor Blade – like a box cutter blade
- ThumbTac or PushPin
- Hole Punch (optional)
- Angle Bracket – or other ‘L’ shaped thingy
- Sandpaper and/or SteelWool
- 3 boards of different thicknesses – I used a 2×4, a 1×4, and a 1/2×4
- 2 empty Arizona Tea Cans (23.5 oz cans)
- 1 full Arizona Tea Can (preferably frozen, or mostly frozen)
- 1 open Arizona Tea Can (for drinking… really, you’re thirsty)
- 1 Starbucks or RedBull can (12 oz can)
- Grease or other lubricant
- 1 non-synthetic cotton ball (optional)
Mount the razor blade to the middle thickness board. This will give you the greatest versatility in adjusting the cutting/scoring height of the blade. In fact, this will give you 7 different effective cutting heights with these three boards.
You’ll want to set the blade in so that is does not stick out far from the wood. The less that sticks out, the less it can bend and the straighter your cut will be.
Start by selecting one of the Arizona cans for your top half, and sand it. The idea with sanding it is not only to remove the paint for a clean looking stove, but to slightly reduce the thickness, since later you will be friction-fitting the top and bottom halves together.
After sanding it to your satisfaction, use a razor to score can along the bottom where the inside ridge meets the concave can bottom. Score this good and carefully. If you press hard enough to cut the metal, you’ll likely bend or crease the can. So, press hard enough to score it good without damaging the can. This will take several times around. Once you’ve got a good score line, pop the bottom out.
Don’t forget to carefully file or sand the edge. It doesn’t have to be perfect, but you might as well make it look good.
Next, we start making the holes.
Many of the “how to build a pop can stove” sites have templates you can print off to get the correct spacing for the holes and recommend specific drill bit sizes. Well, I tried a couple of those and found that they were not worth the trouble. There is no published data showing how the number of holes and/or size of the holes directly (mathematically) relates to the output and/or burn time of the stove. We’re talking about cheap and easy portable stoves here, not nuclear physics.
So, I use an angle bracket and a push pin. The hole on the angle bracket allows me to line the holes up the same distance from the top every time. All I have to do is decide whether I’m putting the holes at the top of the angle bracket hole, or the bottom. For this one, I went with the top – all my previous ones were done at the bottom, and either way works fine.
Pick a spot and make your first hole. To control the hole size, control how much of the push pin you push into the can. However, after making 20+ holes, you’ll find one or two that just go all the way in – so better to just start them all that way.
Now that you have your first hole, turn the can all the way around (180) and make your second one on the opposite side. Yep, eyeball it and guess. We’re not calculating rod height for a specific reactor power. Just get the hole on the opposite side. Then, turn the can so the holes you made are on the left and right, and make another hole right between them. Turn the can over and do the same.
To finish making the jets, simply put holes halfway between each new set of holes. Keep splitting the distance, until you get the number of holes you want. I like to do 32 holes (1, 2, 4, 8, 16, 32), though I do have one with 48 holes where I split the distance between the 16 holes into thirds. The 32 hole can works great.
Now we separate our stove top from the rest of the can. Rest the can on a flat surface against the blade, with the blade board resting blade side down on the 2×4. This will give you a stove top height of roughly 1.25 inches. Again, we’re not putting satellites into space (at least not with a stove this small), so close enough is good enough.
Now carefully rotate the can against the blade until you have gone around a few times and have a good score line. The blade will want to travel “out of true” while rotating, by flexing. So, make small rotations and watch the blade carefully. Once you’ve got a good score line and the blade is catching into the metal, allow it to cut through in one spot to get the separation started.
Now, you’ll push the waste of the can down at the cut, and you’ll see the can slowly shear at the score you made. Pretty easy. If you get to any trouble spots, just set the can back down and carefully go over it again, or come back around from the other side.
When it’s all separated, you should have a finished top that looks like the above picture. Any finish work you attempt at this point may warp or otherwise bend the stove, so leave it alone at this point – or work very carefully.
The bottom of the stove is even easier. For this one, I didn’t even sand the outside of the can (however, we will be thinning it slightly from the inside later).
To make the bottom, simply score the can as before, but with the blade board resting blade side up on the working surface. This should give you a roughly 0.8 to 0.9 inch height. Remember, close enough is good enough.
Score and separate the bottom of the stove from the waste of the can, same as you did with the top of the stove. Once separated, we will be thinning the wall a bit from the inside.
Carefully sand the inside wall of the can. It won’t take much, but you want some good shiny metal, showing that it has been thinned a bit. This will help us when we stretch the bottom out a bit to allow it to fit over the top half of the stove. Get a good band of shiny metal, but be careful – don’t crease or warp it.
Now we need to stretch out the bottom half of our stove. This will be done with a mandrel. You can do this several ways. You can use a frozen (therefore slightly expanded) can, or an unfrozen one with an added thickness.
Since I’ve made several of these stoves, I have a standby mandrel with a cutoff can pressed completely over the bottom of a full can. This will give me enough stretch in the bottom half of the can to let the top half friction fit in.
So, smear some grease on your mandrel, and slowly start working the bottom half of your stove onto it. You don’t want to force it, or you’ll end up with a mandrel like mine and have to cut a new bottom. And, you don’t want it to go all the way on. The compressing air should be enough to keep it from going on further than about a quarter of an inch or so. Remember, we just want to get it stretched enough to start the top into the bottom. It still has to fit tight enough to not need any sealer.
If your stove bottom gets stuck, and doesn’t pop back off due to the compressed air, then you can force it off by carefully heating the stuck part. As you heat it, the compressed air heats, expands, and pressure increases dramatically. You’ll know when you heated it enough because there will be a sudden (loud) pop, something on your garage wall will be knocked onto the floor, and you’ll experience a slight warm trickle in your pants.
Now we can carefully test fit the top and bottom together. Don’t press them all the way together. You simply want to make sure that they get started without too much wrangling around. It shouldn’t be easy, but they should eventually slip together a bit.
Now, we can cut our inner wall out of the RedBull/Starbucks/RandomWhatever can. This is the only part of this building where you have to put any thought and (gasp) measurement into the process. Don’t fret, with my “guess as you go” style, you’ll have your can finished in no time.
What we need is an inner wall that keeps the bottom part of the wall well below the jets, the top half of the stove wall from bottoming out in the bottom half, and yet allows sufficient overlap to provide a tight seal (insert your own “tight seal” joke here).
The inner wall will decide your stove height. Minus the thickness of the top and bottom can metal, the inner wall will be the stove height. So, how do we measure the wall height? Great question.
Before we get too wrapped up in the hows, lets give ourselves a starting point. Make your first score line just like you did for the stove bottom, with the blade board blade side up. Now we know where the inner wall starts.
Then, before separating the can at the score line, set up for the top of the inner wall score line. Stack the 2×4 below the blade board, and adjust the blade board blade side up, or blade side down with shims. Basically you want the wall height to be the height of the stove top, plus the height of the ridge configuration of the bottom half. A little more is okay, but don’t go less.
For rough numbers, you want the inner wall a little over 1.5 inches long. Again, a little longer is okay, up to about 1.75 or 1.80 inches, but don’t go less. Of course, this assumes that you used the same thickness boards as I did, and your stove top and bottom came out to about 1.25 and 0.875 inches respectively.
Remember, the taller your stove, the more top-heavy and unstable it will be, but the more fuel it will hold… kind of a give/take (unlike marriage, which is a give/give).
Once you’ve decided on your inner wall height, stack your boards/shims and make the score line. Then separate the wall from the waste ends.
You should have three pieces that look like this:
Now we need a way for the fuel to get from the central chamber to the outer chamber.
Using a hole punch, line up about half the punch anvil on one edge of the inner wall, and punch out a semi-circle. Any way of cutting a small notch of some kind will do, if you don’t have a hole punch.
Then, you make two more. Just like with the jet holes, just find a good spot evenly spaced and make the holes. They don’t have to be spaced exactly 33.333% apart.
Putting it together:
Now to get the pieces/parts together. Though, there is still one piece missing.
This step can be omitted. In fact, I’m not completely sure it helps. Here’s the deal. Some like to have a wick inside the outer chamber. Most of the wick users like to use some kind of housing insulation. I don’t have any handy, so I’m using a cotton ball.
Theory is, the cotton ball will wick up most of the fuel from the central chamber and into the outer chamber. When you light the central chamber, the flame will be warming up nearly all the fuel, rather than having a cooler pool of fuel that remains below the flame equalized with the outer chamber. There’s a lot more going on, especially after the first five seconds or so, but lets just leave it with – I like to use a cotton ball as an outer chamber wick.
So, unroll the cotton ball and carefully lay it between the stove bottom and the inner wall. Leave it nice and loose. Don’t compress it or push it in. Tear off the unused length of cotton ball.
Also, be sure that the holes along the edge of your inner wall are on the bottom, inside the stove bottom.
Now that you’ve got all the pieces/parts ready and test fit, with the inner wall and cotton wick in place, slowly and carefully slide the top of the stove into the bottom of the stove. You will need to do this slowly and evenly. If you get too much on one side in, it will be difficult to even out without buckling the stove top wall.
While pressing together, pay attention to the inner wall. You should have a good visual gage of when it is properly seated between the top and bottom ridge channels. If the inner wall starts flexing, stop. If your hands are bleeding, stop. Check to ensure it is not catching on the lip, and continue until it is properly and evenly set.
A couple palm taps on a flat surface should be enough to get it set together once you’ve pressed it together.
Lets see, what’s left?… hmmm…
Oh yeah, throw some fuel in there, light it, and watch her go! (see video below, after fully reading this complete disclaimer)
Disclaimer: These instructions are meant to be a general guideline resource, and are experimental in nature. Improper construction of this experimental stove may result in loss of life or limb (or house or spouse). These instructions should be followed carefully, but are not a substitute for seeking appropriate professional and/or knowledgeable (yes, those may be different) assistance with the construction of your stove. These instructions assume a laymen's knowledge and familiarity of basic tools and construction. This should not be your first project - ever. Go build a rocket or something first. If you find yourself sailing up the dark creek of waste product sludge with no mechanical motivation, seek professional help. I am not a professional. In fact, I am currently missing most of the hair on the pointy and middle fingers of my right hand. Your understanding and comprehension of this disclaimer can be verified by PayPal-ing me the sum of $5. Upon receipt of the $5 verification fee (to paypal address of jasonLstone[at]hotmail[dot]com), I will email you a verification reply with a thank you note.
Video of it in Action:
This is a test using 7 cups of water. Not 2 or 4, but 7! The coffee started percolating at the 8 minute mark and was undergoing full boil percolation by 10 minutes. When the fuel went out at 12 minutes, it had easily over 2 minutes of good brewing. Next time, I’ll add a little more fuel.