Introduction: Alcohol / Can / Penny Stove
After reading lots of instructables will varying designs of different alcohol stoves made from drinks cans, I made and tested many different designs and noted down benefits from each. This instructable as been put together based on my final design. It is quick to prime, being ready for your pot less than 20 seconds after lighting and will boil aprox 500ml of cold water to a rolling boil in just under 6 minutes using less than 30ml of meths to light and boil with still some life in it if you needed to retain the water boiling for a little longer.
These figures are based on indoor conditions (please use care indoors and ensure you are in a well ventilated area as I was) using my GSI Outdoors 0.6l tin, I have had better results using an old tragia pot with a larger surface area (4:30 for a rolling boil) however this is too large to use when backpacking. Results do vary when used in cold and windy conditions however this gives you an idea of how it performs.
Step 1: Materials
Ok, so the things you will need are listed below
2x drinks cans
Sand paper (not too course 400grit is about right)
Book / dvd or something similar to rest marker pen on
Baked bean tin
First we want to sand off the paint on the bottom 2inches or so of one can, I found it easier to do this when the can was still sealed with drink in as it was under pressure and less lightly to crumple. We only want to so this on one can however as this will be the outer surface. I used a fairly fine grade of sand paper 400grit as I did not want to damage the surface of the can itself.
Once sanded and you have used the contents :) and rinse out both cans.
Now you have the cans rinsed out you need to make the pin holes.
Using a drawing pin make one hole in the centre of the bottom of the can you have sanded the paint from.
Now we need to make the pin holes for the burner, I found a total of 21 holes worked best, this works out one hole approximately every cm all the way around. On a piece of paper mark out each cm along the edge and cut this as a strip your can wrap around the can and tape in place. If you cut the piece to 20cm long to leave a gap this will make fixing it to the can easiest.
Wrap the paper template around the can leaving a gap between the ends, the edge of the paper should be positioned 5mm from the edge so your pin holes sit on the side, this allows for a pot to be placed directly on the stove. Start in the gap and make a pin hole in the centre of the gap and work around as shown in the picture.
When testing out other stoves I came across charlieCG's stove his was a great inspiration for some of the features of mine, he has some templates you could try out of you wanted to try different hole combinations.
We now need to mark out our lines to cut, the base will be the smallest and is made from the can with paint still on, we have left the paint on as this will be the inside can and once used for the first time the paint will heat up and create a good seal with the outside can.
With your marker make a line all the way around the can 1.5cm from the base (total height from the floor not the lip), I was able to place the marker on a DVD and spin the can around to give me the perfect height.
The outer can needs to be marked 3cm from the base I once again used a few items to fix the marker in place and spin the can making a nice clean even line all the way around.
These measurement can vary a few mm if it makes it easier for you.
With care you now need to cut the cans to size, I found it easiest to rough cut all the way around using a sharp Stanley knife about a cm away from the line and then go in with a pair of scissors and clean up the edges. (if your right handed keep the can on your right hand side this will allow the offcuts to push away from the can without your scissors crumpling the edge of the can)
We now need to crimp the edge of the base can so it fits inside the top can, with your pliers go around the edge of the can, grip about 5mm of the can in the pliers and twist to pull the edge in, complete this every 5mm or so all the way round.
Now the tricky bit, to join the cans together push the top can over the crimped edge of the bottom can, it may take a few attempts but be patient.
If you are unable to get them to fit you can get an additional can and push the base of it in to the top can, roll the edge of the can around inside of the top to try and stretch the top out a bit and make it easier to slip over the base.
Push the top down until it completely cover the paint on the bottom can and is nice and even, be careful not to push it too far as its almost impossible to pull back.
Step 8: Finished
And there you have it, a completed stove, you may want to have a finish up with some more sand paper to get rid of any last bits of paint.
Now the bit I found most important the stand or base, this is simply the top of a baked bean tin cut off to retain the lip, our tin opener fortunately works this way. If your does not and cuts down in to the tin, you may be ale to cut around the base of a tin with a very sharp knife or hack saw and clean the edge up with a file.
I use this base to hold a tiny bit of fuel to prime the stove. Sorry I didn't take any pictures of the stand on its own but I am sure you can get the idea from the image above.
Step 9: Use
Ok so now as always when dealing with fire care needs to be taken as before you know it you can burn yourself.
I have included a video if how to prime the stove. It is important to put the smallest amount of fuel you can get away with into the base and then swirl it around so it sits in the outer rim. If you have too much fuel in the base it will over heat the stove and cause the fuel to evaporate and burn quicker than you want it to, especially with a tin like I use with a small diameter it just wastes heat.
In the video I only fill the top once for demonstration purposes, trial and error will allow you to find the perfect amount for your application, I fill the top to just under the top 3 times (27ml) to boil 500ml of water to a rolling boil with a little left over just in case (there is nothing worse than running out of fuel just before you reach a boil)
Once you have filled with your desired amount of fuel, cover the top hole with your penny and light the fuel in the base, this will heat the bottom of the stove and allow the fuel inside to start vaporising and that is what you want.
Please let me know what you think as I welcome feedback. I have added a guide to what I carry in my kit with my stove so you can see how the full setup compares to the weight of a traditional gas stove.