Intro: Build a Multi-purpose Chimney for Your Pepsi Can Stove
I've built a number of pressure and laminar flow can stoves to learn how to build them from memory and to find the best combination of burner and intake size, jet size, can type, seal type, etc. that would suit my needs. (One thing I'm still looking for is an aluminum can to make a pressure stove like the Swedish Trangia which offers the ability to shutdown and pack up by just screwing on the lid.)
While I have not yet found an aluminum can that is equivalent to the brass Trangia, I have been able to find a single solution that does the following:
1. uses readily found materials
2. supports a "pot" to boil water to heat or cook various trail mix
3. integrates a windscreen that will not blow away
4. reduce lost heat and improve boil time
...by building a chimney for my can stove.
The can stove chimney I built solves all of the problems listed above using readily found 214 or 215 and a 315 tin can. There is room for improvement, however, as far as how the cans are connected and stabilized and what other materials and coatings might be used. (With tin (zinc) coated cans you may want to add some barbecue paint )
Since temperatures can get pretty high its probably best to stay with steel unless you can afford titanium. You can experiment with aluminum if it is thick enough and you are prepared to handle the situation if the aluminum melts out on the trial.
Step 1: The Cans (or Whatever Material You Choose to Use)
I used five cans plus a laminar flow type stove for this example but the pressure stove I used burned hotter with less soot. (BTW - the reason for so much soot is I'm using isopropyl for my experiments.)
Starting from the left with the last can - a mixed vegetable can, it is shown upside down with the top cut out and a 1-1/2" hole cut in the bottom. Holes are easy to cut by first using a punch to knock dots in a 1-1/2" circle which are then cut-connected with a knife.
The next is the "pot" can that holds water for boiling. I used a 16 oz. slim Coconut water beverage can. After the top is popped and the contents consumed the remainder of the top is cut out to make the opening wider and uniform.
Next is a sweetened condensed milk can with both top and bottom removed with a can opener. It is the same diameter as the vegetable can.
Next is another vegetable can with both top and bottom cut out. I had to find one that had a folded seam on both ends in order to do this. 8 holes are punched just under the rim and steel wire inserted to hold a piece of 1/4" hardware cloth which will support the pot.
Next can is the stove.
Next is the bottom can which is a 315 tin can for the air intake unit. Only the top needs to be removed. Punch 8 holes below the rim (or you can go deeper) to receive the steel wire mesh. Hardware cloth can also be added on top of the mesh but I just used the wire mesh by itself.
As you can see neatness is not an absolute necessity for the chimney to work. The wire's job is to support the entire load of the stove, the pot and the rest of the chimney setup so build accordingly.
Step 2: Constructing the Chimney
On a calm day and on flat ground without burying the bottom can in the ground up to about an inch below the rim for greater stability the cans all stack nicely and behave well enough even when the water is at a rolling boil not to need hose clamps and pieces of sheet metal cut from other cans to make a collar or skirt to hold the cans together at each joint - you wish.
For windy or any other unstable condition you must use some means to stabilize the cans. A long piece of flashing might do the job for the top three cans. Conceivably you can also use wire to hang the chimney from a limb or tripod to keep the cans in line.
To start place the stove on the wire mesh of the bottom can and start up the stove. When it needs no more attention and is burning fine place the veggie can with the wire mesh over the stove on top of the bottom can. It will get hot quickly so go as fast as you can without knocking things over.
Next place the pot full of water on top of the veggie can.
Next place the sweetened condensed milk can over the pot and on top of the veggie can.
Next place the last veggie can on top of the sweetened condensed milk can.
Now its just a matter of waiting for the water to boil.
When the water is boiling disassemble the cans in the opposite order, add your ingredients and continue boiling or not as the case may be.